ANNUAL REPORT
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Centre nodes Monash node
Adelaide node
School of Physics and Astronomy Clayton Campus Monash University VIC 3800 T +61 3 9902 4981 E catherine.buchanan@coepp.org.au
1st floor, Physics Building North Terrace Campus The University of Adelaide SA 5005 T +61 8 8313 3533 E sharon.johnson@coepp.org.au
Sydney node
Melbourne node
School of Physics, Building A28 Camperdown Campus The University of Sydney NSW 2006 T +61 2 9351 2482 E diana.londish@coepp.org.au
David Caro Building (Bld 192) Parkville Campus The University of Melbourne VIC 3010 T +61 3 8344 5428 E info@coepp.org.au
Partner institutions
CONTENTS 3
ACRONYMS AND ABBREVIATIONS
44
48 PUBLICATIONS
4 ABOUT
49 51 55 56 57 58 61
5 About CoEPP 6 Director’s report 7 Chair’s report 8 International Advisory Committee’s report 9 Structure and governance 11 Personnel 18 RESEARCH 19 Overview 20 Higgs experimental program 23 Higgs theory program 25 Neutrino theory program 26 Precision tests of the Standard Model 28 Dark matter 31 Searching for supersymmetry 34 Research computing 35 Running and upgrading the experiment 36 Collaborations 38
CONFERENCES AND WORKSHOPS 39 40 41 43
OUTREACH AND ENGAGEMENT
Refereed journal articles ATLAS collaboration Belle collaboration CDF collaboration Refereed conference proceedings Conference presentations CoEPP annual workshop
64 PERFORMANCE 65 66 67 70 72 74 78
Prizes and awards Media report Centre-recognised leadership Key performance indicators Financial statements Financial summary
LOOKING AHEAD 79 82
Activity plan Case study: Searching for new physics with computer vision
2016 CoEPP annual workshop and summer school in Torquay SUSY 2016 INPC 2016 CosPA 2016
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ARC CENTRE OF EXCELLENCE FOR PARTICLE PHYSICS AT THE TERASCALE
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ANNUAL REPORT
ACRONYMS AND ABBREVIATIONS AIDA
An Inclusive Dilepton Analysis
ATLAS
A Toroidal LHC ApparatuS
CERN
European Council for Nuclear Research
CMS
Compact Muon Solenoid
CoEPP
ARC Centre of Excellence for Particle Physics at the Terascale
CP
charge parity
DM
dark matter
fb femtobarn GAMBIT Global And Modular Beyond the Standard Model Inference Tool GeV
giga-electron volt
ICHEP
International Conference on High Energy Physics
IUPAP
International Union of Pure and Applied Physics
KEK
High Energy Accelerator Research Organisation
LHC
Large Hadron Collider
MSSM
minimal supersymmetric Standard Model
NMSSM next-to-minimal supersymmetric Standard Model QCD
quantum chromodynamics
SM
Standard Model of particle physics
SUSY supersymmetry TeV
tera-electron volt
WIMP
weakly interacting massive particle
WLCG
Worldwide LHC Computing Grid
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ABOUT The ARC Centre of Excellence for Particle Physics at the Terascale (CoEPP) is a collaborative research venture between the universities of Melbourne, Adelaide, Sydney and Monash.
ANNUAL REPORT
About CoEPP The Australian Research Council (ARC) Centre of Excellence for Particle Physics at the Terascale (CoEPP) is a collaborative research venture between the universities of Melbourne, Adelaide, Sydney and Monash. CoEPP fosters links between experimental and theoretical particle physics, links Australian research to significant international research centres, establishes strong Australian grid and cloud computing expertise, and further develops accelerator technologies in Australia.
Vision The Centre will exploit a once-in-a-generation opportunity for fundamental scientific research in Australia through its involvement with the Large Hadron Collider (LHC) at CERN. This includes discovering new physical laws, recreating and investigating matter under conditions that have not existed since the big bang, and producing and studying dark matter in the laboratory. The Centre will lead the nation in pursuing knowledge of the fundamental laws of particle physics through a deepening engagement in the international field of high-energy particle physics.
Mission • To enable young Australian scientists direct access to this most exciting field of endeavour on a footing where they will be competitive with their international peers. • To inspire a new generation of young Australians to pursue careers in science and technology. • To lead Australia in the field of high-energy physics research, and to establish national awareness, pride and longevity in this field through international collaboration, excellence in research training and opportunity for engagement.
5 ABOUT
ARC CENTRE OF EXCELLENCE FOR PARTICLE PHYSICS AT THE TERASCALE
Director’s report 2016 marks CoEPP’s sixth year of operation and has been our most productive year to date. We began the year with our biggest ever CoEPP scientific workshop in Torquay, Victoria. More than 150 representatives from Australia and overseas participated. We have expanded the national particle physics program and have an unprecedented number of research students. CoEPP organised major international conferences in Adelaide, Melbourne and Sydney, and cemented collaborative exchange relationships with Fermilab in the United States and the Institute of High Energy Physics (IHEP) in China. The LHC operated beautifully at 13 TeV energy and has delivered a lot more data than was anticipated. More than 40 petabytes of data have streamed through the Worldwide LHC Computing Grid since the LHC restart, and our researchers have been busy analysing these data. The focus now is on precision measurements of the Higgs boson, as well as looking at new ways of searching for supersymmetry (SUSY) and the potential for dark matter production. CoEPP researchers have a strong reputation in various Higgs decay analyses, including the Higgs decaying to a pair of tau leptons, the Higgs to WW channel, Higgs production in association with top quark pairs in leptonic final states as well as Higgs decaying into a pair of photons, and rare and exotic Higgs searches. Our theorists have made important contributions to Higgs studies with development of strategies to measure Higgs boson couplings, model building, and looking at cosmological and astrophysical manifestations of Higgs physics. Theorists continue their research on dark matter with important contributions to the collider search through the mono-X program, as well as indirect detection techniques, and model building. A key legacy of CoEPP has been the theorist–experimentalist connection, which marks us as innovators in the international context. The highly successful pre-SUSY Workshop and SUSY 2016 Conference took place in Melbourne in early July. Thanks to a team effort between CoEPP Monash and Melbourne, the conference had more than 270 participants, 220 abstracts submissions, 31 plenary talks and an intriguing public lecture by Professor John Ellis on dark matter and SUSY. Talks explored the unknown, and probed some new ideas in theoretical and phenomenological aspects of SUSY. Experimental results and future capabilities tempered the theorists’ extravagance with a dash of reality! In September, the Adelaide node hosted the International Conference on Nuclear Physics 2016, together with the Australian National University and the Australian Nuclear Science and Technology Organisation. The large-scale conference attracted international delegates from many laboratories including TRIUMF, JLab, IUPAP and RIKEN. A diverse range of talks reviewed and discussed recent progress and development in nuclear physics research, including the discovery of element 113 at RIKEN. CoEPP Sydney ran the 13th International Symposium on Cosmology and Particle Astrophysics. Latest results and ideas in the areas of particle physics, cosmology and astrophysics were presented over five days in December.
6 ABOUT
Fermilab, the United States major high-energy physics laboratory, and CoEPP recently signed an international Cooperative Research and Development Agreement, which is a significant step in forging active partnerships to tackle shared challenges in physics research. The agreement will initially facilitate exchanges in both directions of researchers, technical staff and students to work on a range of activities, including advanced theoretical physics, precision measurement techniques, advanced research computation methods, underground experimentation and accelerator R&D. We also signed a collaboration agreement with IHEP. Progress continues with the SuperKEKB project at KEK in Japan. Both positron and electron beams were first circulated in February. CoEPP experimentalists are active in pursuing the future program of the Belle II experiment at the unique and important SuperKEKB. The next round of tests is scheduled for mid-2018, with the commencement of the program with a completed detector due from early 2019. With all the very positive results from our current program and the acclaim received, it was with great disappointment we learned of failure in our bid to win funding in the 2017 round of ARC Centre funding. With the unanimous judgement of CoEPP’s success as an ARC Centre and the recognised quality of our work, this result is hard to understand. However, we will continue as a Centre beyond 2017 and are actively following the many constructive ideas proposed to seek avenues for additional funding to continue CoEPP operations beyond the current ARC funding period. Your ongoing commitment and support are much appreciated. They will empower us to develop these ideas into concrete strategies and plans to maintain and expand particle physics research in Australia. I look forward to further developments and will keep you informed as they evolve.
Professor Geoffrey Taylor Centre Director
ANNUAL REPORT
Chair’s report During its 5-year run, the Advisory Board has become really impressed with the number of scientific interfaces that CoEPP manages for the physics community. Best known are the interfaces with CERN and the LHC. These provide scientific opportunities for dozens of Australia’s highly talented and motivated graduate students and early career researchers. CoEPP also interfaces with ANSTO, Australia’s only government laboratory in nuclear physics. In October, I was interested to talk to the then Minister for Industry, Innovation and Science, the Hon. Greg Hunt. He boasted to our small delegation that he ran Australia’s only accelerator, the Australian Synchrotron. Indeed, he does, through ANSTO, which may be better known for running Australian’s only nuclear reactor. CoEPP also interfaces with several international university leaders in high-energy physics and national labs, such as the United States Department of Energy’s Fermilab, also visited by the Minister in October. CoEPP is our link to new accelerators in Asia and to the Nobel Prize–winning Japanese research effort in neutrino physics.
CoEPP is home to Australia’s astroparticle research. Some of the most interesting questions in physics, such as the nature of dark matter and the dominance of the universe over the antiparticle universe, will likely be answered in the coming decades, and Australia’s contribution to answering these and other questions will come from CoEPP or its successor.
Given all CoEPP’s opportunities and interfaces, an Australian Centre of Excellence in particle physics is greatly needed, and we expect to apply to the ARC at the next opportunity. But there may be some real opportunities earlier than that. The Advisory Board is exploring these options.
Professor Jeremy Mould Chair, Advisory Board
It is time to rethink what CoEPP’s successor will be, and our Advisory Board is now engaged with that question. Some will consider it surprising that CoEPP will not immediately be renewed by the ARC when funding is fully expended in 2018. However, physics is in such an exciting phase now that it is hard to criticise the ARC for investing in such irresistible opportunities as the Future Low-Energy Electronics Technologies (FLEET) centre, rather than renewing CoEPP. FLEET points out to all of us that the power used by our smart phones is not just battery power; it’s the gigawatts used by servers at remote companies providing instant answers to these communicators. When that’s added in, we’re told, our smart phone uses as much power as our fridge. Australia wants to contribute to finding the replacement for the humble transistor, too. There is an embarrassment of opportunities in physics and insufficient research funds to take up all these challenges.
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ARC CENTRE OF EXCELLENCE FOR PARTICLE PHYSICS AT THE TERASCALE
International Advisory Committee’s report The International Advisory Committee (IAC) is made up of leading particle physics researchers; it meets once a year to discuss and guide the scientific direction of the Centre. The 2016 meeting of the IAC and Partner Investigators was held on 11 August, at the University of Chicago, immediately following the International Conference on High Energy Physics (ICHEP). Present were IAC Chair Rolf Dieter-Heuer, and members Peter Jenni, Young-Kee Kim (new to the IAC) in person and John Ellis by teleconference. Also present were Partner Investigators, Karl Jacob and Allan Clark in person, and Andy Parker, Mark Kruse and Chiara Meroni by teleconference. CoEPP members Geoffrey Taylor (Director), Tony Williams, Paul Jackson, Peter Skands and Tony Limosani were also present. The main item of business was the status of the proposal to the ARC for a second 7-year funding round for Australian high-energy physics. Although we now know that the proposal was unsuccessful, it was satisfying to see the IAC’s confidence in our ability to build upon the strengths already in place and our capability of carrying out the very significant plans clearly stated in the proposal. In parallel with the Centre renewal proposal, a description of the upcoming ARC Linkage Infrastructure, Equipment and Facilities (LIEF) funding round was provided. The IAC encouraged us in plans to participate in the major ATLAS Phase II Upgrade in which, in particular, the existing Inner Detector will be completely replaced by an all-silicon inner-tracking detector, “ITK”. With our expertise in silicon detector development and construction, in advanced track trigger electronics and programming, and in data acquisition, the
IAC member Professor Karl Jakobs, ATLAS collaboration spokesperson from 2017
8 ABOUT
Australian participation – through CoEPP – in the ITK Upgrade has many advantages. Of note from the IAC was the very impressive increase in student numbers throughout CoEPP’s operation. They asked about the gender balance among our students, which compares very well among physical sciences research groups; CoEPP will continue to work to improve the gender ratio. The IAC also noted that the large number of international research students seeking a place with CoEPP was clear recognition of our esteem worldwide. The IAC noted the large number of major conferences being held by CoEPP and its members and encouraged the idea of holding preand post-conference workshops to offset the large distance travelled by colleagues in the northern hemisphere. CoEPP was encouraged to continue its successful outreach program, with the suggestion that events in cities and large centres in Australia without a CoEPP node be pursued to broaden national exposure. CoEPP also congratulated Partner Investigator Professor Karl Jacob for being elected spokesperson of the ATLAS collaboration from January 2017. Karl follows in the footsteps of very significant ATLAS leaders Peter Jenni (also an IAC member), Fabiola Gianotti and David Charlton.
ANNUAL REPORT
Structure and governance The operation of the Centre is managed through committees and management teams. The organisational structure is designed to support a focused, coordinated program and to sustain the ability to deliver change over an extended period.
Operation and management The Centre management structure comprises the Director, Professor Geoffrey Taylor; the Associate Director, Professor Anthony Thomas; and the four node directors who manage local node issues. These staff comprise the Centre Executive Committee, which meets monthly throughout the year in four face-to-face meetings – one at each node – and at other times by teleconference, to ensure as wide participation as possible, given the varied travel schedules of the members. A Centre Manager supports the Director and the executive team, and oversees administrative, IT, outreach and communications support for the Centre. The Centre Manager also works with node directors to ensure the proper flow of accounting information between the Centre and the nodes. Financial statements are generated quarterly and financial reports are presented annually to the board, with interim statements at the half-yearly meetings. Two other key roles in the Centre comprise Outreach and Communications, and Research Computing. Outreach activities include national and local programs for school students, as well as public outreach programs; communications activities include public-facing elements such as media liaison, promotion of the Centre, its research and researchers, and management of web and social media. The Centre Research Computing facility enables the Centre to maintain its pledge to the Worldwide LHC Computing Grid by providing Tier 2 computer facilities to the ATLAS experiment and local analysis support for the Centre’s experimental researchers and students.
Advisory Board Chaired by Professor Jeremy Mould, the Advisory Board meets every 6 months to provide advice to the Centre Director; and to provide oversight, review and comment on matters of strategic direction, the conduct of research and other relevant Centre activities. The board met at the CoEPP Annual Scientific Workshop in Torquay in February and at the University of Melbourne in September. Members of the board are: • Professor Jeremy Mould (Chair), Professor of Astrophysics, Swinburne University • Mrs Sarah Brooker, Managing Director, Science in Public • Professor Mike Brooks, Deputy Vice-Chancellor (Research) University of Adelaide • Professor Karen Day, Dean of Science, University of Melbourne (Deputy Vice-Chancellor (Research) nominee) • Professor Bruce McKellar AC, President, International Union of Pure and Applied Physics, and Honorary Professorial Fellow, University of Melbourne • Professor Michael Morgan, Head, School of Physics, Monash University (Deputy Vice-Chancellor (Research) nominee) • Dr Adi Paterson, Chief Executive Officer, Australian Nuclear Science and Technology Organisation • Professor Michael Thompson, Professor in Zoology, University of Sydney (Deputy Vice-Chancellor (Research) nominee).
Centre Advisory Committees International Advisory Committee The IAC meets annually and provides independent scientific expertise, advice and experience from established research centres and leading international laboratories. Members of the IAC met in August during ICHEP 2016 in Chicago, and were briefed on recent Centre activities. Members of the IAC are: • Professor Rolf-Dieter Heuer (Chair), President of Deutsche Physikalische Gesellschaft (German Physical Society) • Professor Hiroaki Aihara, Vice President, University of Tokyo, and Associate Director, Institute for the Physics and Mathematics of the Universe, Japan • Professor John Ellis, CERN, and Clerk Maxwell Professor of Theoretical Physics at King’s College London, United Kingdom • Professor Peter Jenni, CERN, and Guest Scientist with the Albert-Ludwigs-Universität, Freiburg, Germany • Professor Young-Kee Kim, Louis Block Professor of Physics, University of Chicago, United States (from July 2015).
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ARC CENTRE OF EXCELLENCE FOR PARTICLE PHYSICS AT THE TERASCALE
Meeting schedules Meeting
Attendees
Frequency
Timing/venue
International Advisory Committee
IAC and Director
Annually
Held during ICHEP in August
Advisory Board
Advisory Board and Director Centre academics were also invited to the Torquay workshop meeting
6-monthly
Held at the Torquay workshop in February and at the University of Melbourne in September
Centre Executive
Director, Executive Committee, Centre Chief Investigators and academics
Monthly
Four face-to-face meetings per year; remaining meetings by teleconference
CoEPP Experimental Particle Physics Group
Experimental particle physics staff and students from Melbourne, Adelaide and Sydney universities
Weekly
Teleconference between the three experimental nodes of the Centre
Internal Annual Research Workshop
All CoEPP research and administration staff and students, and representatives from Partner Institutions, IAC and Advisory Board
Annually
Held in Torquay in February
Theory Group Journal Club
Theory researchers and students from all nodes
Weekly
Held by teleconference between all nodes
CoEPP governance structure
International Advisory Committee
Director
Advisory Board
Professor Geoffrey Taylor
Associate Director
Centre Manager
Professor Anthony Thomas
David Varvel
Research Computing Manager Lucien Boland
Melbourne Node Director Professor Raymond Volkas
10 ABOUT
Adelaide Node Director Professor Anthony Thomas
Senior Communications and Outreach Consultant Caroline Hamilton
Monash Node Director
Sydney Node Director
Associate Professor Csaba Balázs
Professor Kevin Varvell
ANNUAL REPORT
Personnel Chief investigators
Professor Geoff Taylor Centre Director University of Melbourne
Associate Professor Csaba Balázs Node Director Monash University
Professor Anthony Thomas
Professor Kevin Varvell
Node Director University of Adelaide
Node Director University of Sydney
Professor Ray Volkas
Professor Elisabetta Barberio
Associate Professor Nicole Bell
Dr Antonio Limosani
Node Director University of Melbourne
University of Melbourne
University of Melbourne
University of Sydney
Associate Professor Martin Sevior
Professor Anthony Williams
Dr Bruce Yabsley
University of Adelaide
University of Sydney
Associate Professor Ross Young
University of Melbourne
University of Adelaide
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ARC CENTRE OF EXCELLENCE FOR PARTICLE PHYSICS AT THE TERASCALE
Additional academic staff
Dr Matthew Dolan
Dr Robert Foot
University of Melbourne
Senior Researcher, University of Melbourne
Dr Michael Schmidt University of Sydney
Associate Professor Peter Skands ARC Future Fellow, Monash University
Dr Martin White ARC Future Fellow, University of Adelaide
12 ABOUT
Associate Professor Paul Jackson ARC Future Fellow, University of Adelaide
Dr Archil Kobakhidze ARC Future Fellow, University of Sydney
Dr Phillip Urquijo
Prof German Valencia
ARC Future Fellow, University of Melbourne
Monash University
ANNUAL REPORT
Honorary fellows and associates
Professor Allan Clark
Dr Shivani Gupta
Dr Girish Joshi
Dr Katherine Mack
University of Geneva, Switzerland
Visiting Research Associate, University of Adelaide
Honorary Principal Fellow, University of Melbourne
Honorary Fellow, University of Melbourne
Professor Bruce McKellar AC
Associate Professor Lawrence Peak
Dr Brian Petersen
Dr Aldo Saavedra
Honorary Fellow, University of Melbourne
Honorary Fellow, University of Sydney
Honorary Professorial Fellow, University of Melbourne
Honorary Fellow, University of Sydney
Partner investigators
Professor Tony Gherghetta
Professor Karl Jacobs
Professor Mark Kruse
Professor Chiara Meroni
University of Minnesota, United States
University of Freiburg, Germany
Duke University, United States
Istituto Nazionale di Fisica Nucleare, Italy
Professor Andy Parker
Professor Mark Trodden
University of Cambridge, United Kingdom
University of Pennsylvania, United States
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ARC CENTRE OF EXCELLENCE FOR PARTICLE PHYSICS AT THE TERASCALE
Postdoctoral researchers University
Name
Monash University
Sujeet Akula Peter Athron Andrew Fowlie Haitao Li Tong Li
University of Adelaide
Juan Herrero Garcia Lawrence Lee Marek Lewicki Jinmian Li Hrayr Matevosyan Roman Nevzorov Andreas Petridis Pankaj Sharma
University of Melbourne
James Barnard Giorgio Busoni Yi Cai Tyler Corbett Noel Dawe David Dossett Takashi Kubota Chunhua Li Federico Scutti Francesco Tenchini Francesca Ungaro Zhao-Huan Yu Daniele Zanzi
University of Sydney
Kevin Finelli Kristian McDonald Anthony Morely Jin Wang Lei Wu
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Participants at CoEPP's annual scientific workshop
ANNUAL REPORT
Students University
Study
Name
University
Study
Name
Monash University
Honours
Andrew Lifson
University of Melbourne
Masters
Wesam Badr
Shi Qiu PhD
University of Adelaide
Honours
Masters
PhD
Innes Bigaran
Cody Duncan
Byung Cheon
Nadine Fischer
Patrick Dawson
Giancarlo Pozzo
Shanette de la Motte
Graham White
Joshua Ellis
Paul Alvino
Benjamin Graham
Joshua Crilly
Stephen Keyte
Jake Guscott
John Koo
Patrick Riley
Ibtihal Mahmood
Luciano Carneiro-Guedes
Peter McNamara
Guy Pitman
Roberto Munoz
Harry Poulter
Nina Rajcic
Stephen Tronchin
Tristan Ruggeri
Ankit Beniwal
Martine Schroor
Damir Duvnjak
Kim Smith
Dylan Harries
Christian Sotomayor
Sophie Hollitt
Aghuistin Steele
Nicolas Ivancevic
Justin Tan
Kay Marie Martinez
Scott Williams
Zachary Matthews
Table continued over page
Daniel Murnane Jason Oliver Robert Perry Anum Qureshi Filip Rajec Marco Santoni Andre Scaffidi Abhishek Sharma Sophie Underwood
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ARC CENTRE OF EXCELLENCE FOR PARTICLE PHYSICS AT THE TERASCALE
University
Study
Name
University
Study
Name
University of Melbourne (continued)
PhD
Tristan Bloomfield
University of Sydney
Honours
Ruihao Li
Masters
Nadia Toutounji
Amelia Brennan Giacomo Caria Jackson Clarke
Somasuntharam Arunasalam Neil Barrie
Tomasz Dutka
Curtis Black
Alexander Ermakov
Rupert Coy
Leon Friedrich
Bahman Ghadirian
Johnathan Gargalionis
Cyril Lagger
Anton Hawthorne-Gonzalvez
Shelley Liang
Chia-Ling Hsu
Adrian Manning
Anders Huitfeldt
Mark Scarcella
David Jennens
Alex Spencer-Smith
Brian Le
Carl Suster
Rebecca Leane
Matthew Talia
Stephen Lonsdale
Jason Yue
Lara Mason Millie McDonald Marco Milesi Francesco Nuti Luis Pesantez Joni Pham Pere Rados Isaac William Sanderson Laurence Spiller Thor Taylor Timothy Trott Eiasha Waheed David Wakeham James Webb
ABOUT
PhD
Peter Cox
Caitlin MacQueen
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Lachlan Vaughan-Taylor
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Professional staff Name
Position
Node
Mr Tiziano Baroncelli
Engineer, Belle II
University of Melbourne
Mr Tommaso Baroncelli
Engineer, Belle II
University of Melbourne
Mr Lucien Boland
Research computing manager
University of Melbourne
Dr Goncalo Borges
Research computing officer
University of Sydney
Dr Catherine Buchanan
Monash node administrator
Monash University
Mr Alessandro Caronti
Project administration officer
University of Melbourne
Mr Sean Crosby
Research computing administrator and developer
University of Melbourne
Mr Stephen Gregory
Engineer
University of Melbourne
Ms Caroline Hamilton
Senior communications and outreach consultant
University of Melbourne
Ms Ying Hu
Melbourne node administrator
University of Melbourne
Ms Winnie Huang
Centre administrator and PA to Director
University of Melbourne
Ms Sharon Johnson
Adelaide node administrator
University of Adelaide
Dr Diana Londish
Sydney node administrator
University of Sydney
Dr Padric McGee
IT support
University of Adelaide
Ms Mary Odlum
Finance Officer
University of Adelaide and University of Melbourne
Ms Silvana Santucci
Adelaide node administrator
University of Adelaide
Ms Tracy Sproull
Finance Officer
University of Melbourne
Mr David Varvel
Centre manager
University of Melbourne
17 ABOUT
RESEARCH CoEPP is the foremost particle physics research centre in Australia. Centre members undertake groundbreaking and transformational particle physics research, and work on the most pressing questions in the field, including tests of the Standard Model of particle physics (SM), Higgs boson properties and Higgs decay analysis, new physics beyond the SM, supersymmetry (SUSY) and dark matter (DM). A major focus of research within CoEPP is the ATLAS experiment at CERN.
RESEARCH
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Overview CoEPP’s work at ATLAS includes the analysis of Higgs boson decay modes (which is vital for characterising the Higgs boson), and the development of new and refined theoretical models and analysis techniques. Centre work studies physics beyond the SM, the search for the origins of neutrino mass, fine-tuning constraints in supersymmetric models and the elusive search for DM. Theoretical work underpins the experimental studies, with theorists and experimentalists working collaboratively on the many areas of study in the Centre’s rich research program. Cross-node collaboration is
strong. Theoretical and experimental researchers across the nodes meet weekly via teleconference. CoEPP researchers also work with individuals across the globe on specific projects and, besides ATLAS, are members of many other particle physics collaborations, including Belle II and GAMBIT.
XXXX
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ARC CENTRE OF EXCELLENCE FOR PARTICLE PHYSICS AT THE TERASCALE
Higgs experimental program Researchers
Introduction
Elisabetta Barberio
The discovery of the Higgs boson was the most significant achievement of the ATLAS and CMS experiments in the first period of data taking (Run 1) from the LHC, and proved that the SM is a self-consistent theory. After a 2-year shutdown for essential upgrades, the LHC began its Run 2 phase in 2015, with collisions set at the unprecedented energy of 13 TeV. In 2015 and 2016, the LHC delivered more than 40 fb-1 of proton–proton collision data – more than projected. With even more data expected in 2017, the Higgs research program is in full swing once again. Now that the discovery of the Higgs boson has been well established, Higgs searches have turned into precision measurements. The aim is to measure – as precisely as possible – all the properties of the new particle and compare them with the SM predictions. Deviations may give hints of extensions of the SM with other Higgs boson partners, or of new physics at higher energy scales.
Noel Dawe Paul Jackson Takashi Kubota Lawrence Lee Tony Limosani Anthony Morley Geoffrey Taylor Kevin Varvell Jin Wang Martin White Daniele Zanzi
Students Curtis Black David Jennens Brian Le Marco Milesi Francesco Nuti Jason Oliver Pere Rados Laurence Spiller Thor Taylor
CoEPP researchers have been actively studying the 13 TeV data of Run 2. Parts of the ATLAS detector and of the data acquisition and event reconstruction software have been upgraded, and properties of the proton collisions have changed with respect to Run 1. That meant that the ATLAS detector and software had to be thoroughly commissioned with the new data. CoEPP researchers contributed to the recommissioning and are now involved in the wide range of Higgs analyses outlined below.
Research H → ττ The search for the Higgs boson decaying into pairs of tau leptons is the most sensitive analysis for discovering and measuring the Higgs boson coupling to fermions. Preliminary results released in 2013 showed strong evidence for Higgs boson decays into tau leptons. This result was updated in 2014, based on the full dataset collected by the ATLAS experiment during the first period of LHC data taking, corresponding to about 5 fb–1 of proton– proton collisions at a centre-of-mass energy of 7 TeV and about 20 fb–1 at 8 TeV. The updated result (JHEP 4, 117 [2015]), shows a clear excess of events, with a significance of 4.5 standard deviations above the background-only hypothesis. This is the strongest evidence so far for the Higgs boson coupling to fermions. Under the hypothesis that the Higgs boson is produced and decays to tau leptons, the measured cross-section is 1.4 ± 0.4 times the one predicted by the SM, and the measured Higgs boson mass is
20 RESEARCH
about 125 GeV, which is compatible with the mass measured more accurately in separate analyses of events where the Higgs boson decayed into pairs of vector bosons. One of the main challenges in the H → ττ analysis is to efficiently reconstruct and identify the hadronic decays of the tau leptons. These tau lepton decays occur with the highest probability, but the resulting hadrons are difficult to distinguish from jets of hadrons produced by fragmenting quarks and gluons emitted from the proton–proton collisions. CoEPP researchers have a longstanding and significant contribution in both the search for H → ττ and the reconstruction and identification of the hadronically decaying tau leptons. CoEPP researchers are also leading the search for these decays by targeting one specific production mode: Higgs boson production in association with a vector boson (VH). This production mode is subleading with respect to those exploited in the main H → ττ search, but observing this rare process is relevant for determining Higgs boson properties and testing SM predictions. Analysis of the data (20 fb–1) collected at 8 TeV centre-of-mass energy was published in Physical Review D (Phys. Rev. D 93, 092005). An upper exclusion limit on the production cross-section times branching ratio for VH (→ττ) events is set at 5.6 times the SM prediction, and the signal cross-section is measured to be 2.3 ± 1.6 times the SM prediction. Dr Geng-Yuan Jeng, a former CoEPP researcher, coordinated the analysis. Jeng, Daniele Zanzi and PhD students Curtis Black and David Jennens established a data-driven method for estimating background events with misidentified muons and electrons and hadronically decaying tau leptons. The method is expected to have wider applications in other physics searches. PhD student Brian Le, with Jennens and Zanzi, pioneered a multivariate approach for estimating the background events from production of two vector bosons. Elisabetta Barberio edited the paper submitted to Physical Review D. CoEPP researchers are also fully committed to the ATLAS H → ττ analysis for the current period of LHC data taking. The sensitivity for a discovery at 5 standard deviations is expected to be reached in Run 2. Beginning in 2015, Barberio took on the role as convenor of the analysis team. PhD student Laurence Spiller developed an improved multivariate analysis of the Run 2 data in the fully hadronic final state, using new topological variables he developed (JHEP 03, 027). Zanzi and PhD students Brian Le and Pere Rados contributed to the data acquisition software for events with hadronically decaying taus and to calibrating the energy measurement of such particles. Zanzi is also leading the design of the measurement of the Higgs boson charge parity (CP)
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quantum number in the Higgs boson decays into tau leptons. This is a complex analysis because of the difficulty in selecting the signal events and the need for a precise reconstruction of the tau lepton decays. Nonetheless, this analysis will be one of the most sensitive measurements for the Higgs boson CP quantum number, with important implication for the indirect search for physics beyond the SM.
H → WW In Melbourne, Takashi Kubota and PhD student Pere Rados continue to lead efforts to measure the crosssection of Higgs bosons produced in association with a W boson in the final state where the Higgs boson decays into a pair of W bosons (WH → WWW). This channel allows Higgs boson couplings to W bosons to be directly measured. Kubota was the coordinator of the WH → WWW analysis group and edited the first publication from the H → WW group that was based on 13 TeV data (ATLAS-CONF-2016-112). So far, this has been the only publication in the H → WW decay with 13 TeV data and is therefore significant for Higgs boson studies in ATLAS. Rados lead the WH → WWW analysis in the final state with three leptons, and was in charge of outlining the Run 2 trigger strategy for all H → WW analyses. In Adelaide, Paul Jackson and PhD student Jason Oliver also joined the H → WW efforts, working on signal extraction methods and characterisation for the H → WW events produced by gluon fusion.
ttH → leptons CoEPP researchers in Melbourne are making crucial contributions to the search for Higgs boson production associated with top quark pairs (ttH) in leptonic final states. The search for this rare Higgs boson production mode is one of the ATLAS flagship analyses in the LHC Run 2. The observation of ttH events provides a direct measurement of the Higgs boson coupling to top quarks, with significant implications for searches for new physics beyond the SM. In the analysis of the 20.3 fb–1 of 8 TeV data, in which PhD student Francesco Nuti, Barberio and Zanzi were involved,
an excess of events corresponding to 2.1 + 1.4 − 1.2 times the SM expectation were observed (Phys. Lett. B 749:519–541 [2015]). In 2016, the preliminary analysis of the first 13.2 fb–1 of proton–proton data collected at 13 TeV confirmed the result, measuring a ttH cross-section 2.5 + 1.3 − 1.1 higher than the SM prediction (ATLAS-CONF-2016-058), as shown in Figure 1. PhD student Marco Milesi, Barberio and Zanzi worked on determining the background events with mis-reconstructed leptons in events with two leptons with same electric charge – the most sensitive final state. They are now analysing the full dataset collected in 2016, which is 2.5 larger than the one already analysed, to provide the first evidence of the ttH production. Milesi, Barberio and Zanzi are re-optimising the trigger selection strategy and improving the background estimate to reach even higher sensitivities.
H→ γγ, Zγ Decays into pairs of photons are particularly attractive for studying the properties of the Higgs boson, thanks to the high photon reconstruction and identification efficiency and the excellent photon energy resolution at ATLAS. CoEPP researchers in Sydney are taking leading roles in searches for both the SM Higgs boson and for a high mass resonance in decays to photons and other bosons. Jin Wang has been responsible for generating and validating the simulation used in the H → γγ analyses. Wang has also been one of the leading contributors in measuring the Higgs boson production cross-section by vector boson fusion (VBF) using the H → γγ decay. With collaborators at IHEP in China, Wang developed a multivariate method to maximise the sensitivity of the VBF H → γγ signal against nonresonant backgrounds, including events with misidentified photons, and resonant backgrounds, such as H → γγ events produced by gluon fusion. Preliminary results on the first 13.3 fb−1 of Run 2 data have been presented at ICHEP 2016 (ATLASCONF-2016-067). In addition to producing the cross-section measurement, Wang is working on
Figure 1 Best fit values of the ttH cross section in units of SM prediction by final state category and combined.
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measurements of Higgs boson properties, such as its spin and CP quantum numbers. He contributed to the introduction of the so-called “optimal observables”, variables that combine multidimensional information from the production and decay matrix elements in the H → γγ analyses. These variables provide sensitivity to the spin and CP quantum numbers, as well as to higher-order operators beyond the SM, in an effective field theory approach. Wang also contributes to the search for the production of WWγγ events, with one SM Higgs boson decay into photons and the WW pair produced either by the decay of a second SM Higgs boson or by a heavier scalar beyond the SM. Anthony Morley and Tony Limosani are two of the leading contributors in the search for H → Zγ decays. Measurements of (or limits on) the H → Zγ decay rate can provide insight into models beyond the SM. The decay rate can help determine whether the new boson is the Higgs boson or a member of other electroweak singlets or triplets. Furthermore, the H → Zγ process is the only decay of the Higgs to electroweak gauge bosons yet to be observed. This measurement will also be able to complement the precise measurement of the Higgs boson mass already made from measurements of the H → γγ and H → ZZ decays. Morley and Limosani are also leading the search for a high mass resonance in decays to the Z-boson plus photon final state. Preliminary results using 13.2 fb–1 of proton–proton data collected at 13 TeV were presented at ICHEP (Figure 2). Morley was co-editor
Figure 2 Distribution of the reconstructed Zγ invariant mass in events including the Z boson decays to electrons and muons. The solid lines show the results of background-only fits to the data. The residuals of the data points with respect to the fit are also shown.
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of this paper (ATLAS-CONF-2016-044) and led trigger studies, while Limosani was co-editor of the supporting documentation and did background modelling studies.
Rare and exotic Higgs searches CoEPP researchers are also involved in several searches for rare Higgs boson decays and for heavier Higgs boson partners beyond the SM. In Melbourne, Zanzi has been involved in the search for the rare Higgs boson decay into a Φ meson and a photon (Phys. Rev. Lett. 117, 111802) to probe the Higgs boson couplings to light quarks. Zanzi developed the trigger algorithm that selected the 2.7 fb–1 of proton–proton data at 13 TeV analysed in this search. In Adelaide, Lawrence Lee and Martin White have been involved in analysing the observed excess of events with two photons with invariant mass of 750 GeV in the 3.2 fb−1 of data at 13 TeV recorded in 2015 (JHEP 1609, 001). They developed a model for the narrow and high mass signal to be used in simulation.
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Higgs theory program Introduction CoEPP theorists continued investigating the properties of the Higgs boson in light of the experimental data from the LHC. The goal of this research is to understand the dynamics of electroweak symmetry breaking and uncover new physics phenomena associated with it. Theoretical investigations in this direction also have far-reaching implications for understanding the history of our universe. The observed dominance of matter over antimatter and hence, ultimately, our existence, may indeed be determined by the properties of Higgs boson interactions. Among the key research directions of the CoEPP Higgs theory program are: • theoretical studies of various strategies to measure the Higgs boson couplings at the LHC and future colliders • model building that allows electroweak symmetry breaking to be placed within a more complete and consistent theoretical framework • uncovering subtle cosmological and astrophysical manifestations of Higgs physics. In 2016, CoEPP researchers obtained a number of interesting results in these areas.
Higgs collider phenomenology The precision characterisation of the properties of the Higgs boson is one of the most important
research areas for the future runs of the LHC, and a key motivation for planned future colliders. One of the most important of the couplings is that between the Higgs boson and a pair of top quarks, the heaviest quarks in the SM. The nature of this coupling has significance for the hierarchy problem and in various cosmological models, and has drawn the attention of a number of CoEPP researchers this year.
Researchers
Matthew Dolan, Zhao-Huan Yu and overseas collaborators (Phys. Rev. D 94, 01525) studied possible LHC measurements of top-quark couplings to additional Higgs bosons that may exist in several models beyond the SM. Archil Kobakhidze, Lei Wu and Jason Yue (JHEP 1604, 011) studied alterations in the same top-Higgs couplings and in Higgs self-couplings, and their possible relationship with the matter–antimatter asymmetry of the universe. These models may be constrained through future LHC measurements, as was further explored by the same authors, with Ning Liu, in a more recent paper (in press with JHEP). Many models beyond the SM predict the existence of charged Higgs bosons. New strategies to search for these at the LHC have been presented by Li, Riley Patrick, Pankaj Sharma and Anthony Williams (JHEP 1611, 164).
Paul Jackson
Planning is already underway within the particle physics community for future colliders, and CoEPP researchers have been active in studying the physics possibilities such facilities would offer. Yu et al. (Phys. Rev. D 93, 105315) studied how a future electron–positron collider could constrain models of electroweak baryogenesis in a model-independent way. Csaba Balázs, as part of a larger international effort (to appear in the European Physical Journal C),
Peter Athron Csaba Balázs Tyler Corbett Matthew Dolan Archil Kobakhidze Ning Liu Anthony Williams Lei Wu Zhao-Huan Yu
Students Somasuntharam Arunasalam Dylan Harries Cyril Lagger Shelley Liang Adrian Manning Patrick Riley Marco Santoni Pankaj Sharma Jason Yue
Figure 1 This figure shows the estimated production cross-section required in order to be able to discriminate between different new particles (scalar, pseudoscalar, vector or axial vector) produced in association with a pair of top quarks at the LHC, using the invariant mass of the two top quarks.
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has contributed to a large study of Higgs physics at the electron–positron Compact Linear Collider. Another important Higgs coupling is to the tau lepton, since it may be the only leptonic Higgs coupling measurable at the LHC. This coupling is particularly challenging because of the decaying tau leptons. Two groups from CoEPP – Andrew Fowlie and collaborators (in press with Nucl. Instrum. Meth.) and Li and Williams (Phys. Rev. D 93, 075019) – have proposed new methods to reconstruct the Higgs boson mass in such decays using advanced statistical techniques. Finally, Dolan et al. (JHEP 1607, 039) have studied the collider signatures of a simplified model incorporating a new singlet scalar field and its relation to effective field theory approaches.
New theory models and ideas An area of particular excitement in the high-energy physics community early in 2016 was the emergence of a “bump” in the diphoton mass spectrum observed at both the ATLAS and CMS experiments. This possible signal of new physics prompted a swift response from several CoEPP researchers in the form of papers, most of which described building new models to explain the apparent excess, while others focused on the constraints from previous measurements. Lei Wu and collaborators (Phys. Lett. B 759, 191) showed how anomaly-mediated SUSY breaking could accommodate a Higgs-like particle, which could explain the diphoton signal, while simultaneously explaining the apparent anomaly in the magnetic moment of the muon. Further work by Wu et al. (Phys Lett. B 756, 309) demonstrated
Figure 2 This figure shows the current constraints (in the left-hand panel) from the LHC on anomalous couplings between the top quark and the Higgs boson, and in the right-hand panel the prospects for improvement by including data from the ongoing Run 2.
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how an extension of the popular two-Higgs doublet model could also be made consistent with the diphoton excess. Yu et al. (Phys. Rev. D 93, 075033) also constructed an extra-dimensional model in which the resonance appeared as a singlet scalar particle. Two other significant papers were on constraints on the putative particle at 750 GeV. One was by Yu and collaborators (Nucl. Phys. B 909, 43), which quantified the effects of the wide variety of searches for DM on scenarios capable of explaining the excess. Another paper, by Peter Athron et al. (Eur. Phys. J. C 76, 516), undertook a detailed analysis of a large number of theoretical scenarios, using the FlexibleTools framework to correct a number of errors and misconceptions in the literature. Fowlie et al. (JHEP 1608, 100) studied the naturalness of the recently proposed relaxion solution of the electroweak hierarchy problem. Using a Bayesian statistical approach, they argue that the SM is actually favoured over the relaxion because of the extensive fine-tuning the relaxion involves. Athron and collaborators (Comput. Phys. Commun. 202, 113) have been studying precision predictions of the Higgs boson mass in several different theories of beyond the SM physics, including the next-to-minimal supersymmetric SM (NMSSM) and an effective field theory context (JHEP 1701, 079), which have resulted in public codes being made available as part of the FlexibleTools framework. Athron et al. have also been studying the detailed Higgs phenomenology of the E6-extended minimal supersymmetric SM (E6SSM) in a series of papers (Phys. Lett. B 760, 19; JHEP in press).
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Neutrino theory program Introduction
generation is incorporated. Various scenarios were examined in these papers.
Researchers
While the experimental discovery of neutrino flavour transformations and oscillations – the subject of the 2015 Nobel Prize in Physics – proves that neutrinos have mass and quantum mechanical mixing, the mechanism by which they acquire those masses and mixing parameters remains unknown. In particular, the fact that neutrino masses – though nonzero – are so much smaller than the other types of leptons and quarks suggests that they obtain their masses in a different manner. One approach to explain this encompasses the so-called “seesaw models”, where the neutrino masses are inversely proportional to a high mass scale of new physics.
McDonald and collaborators also examined “scotogenic” and scale-invariant models (JHEP 1606, 182), with some of this work involving PhD student Adrian Manning (Phys. Rev. D 94(5), 053005). The term “scotogenic”, coined by Ma, refers to neutrinos gaining their masses through interactions with DM. Scale invariance is the hypothesis that all particles, including the Higgs boson, are massless at the classical level. Thus, the origin of all elementary particle masses, not just those of neutrinos, is proposed to be purely quantum mechanical. Some of the new particles required by these models can be searched for at the LHC.
Yi Cai
Another possibility, which was the focus of much of the CoEPP research in 2016, is that neutrino masses are generated “radiatively”. This means that neutrinos are massless at the classical level, but obtain masses when the quantal effects of virtual particle exchange are considered. Some of these virtual particles must be exotic, meaning not in the SM. Such particles can potentially be produced at the LHC, a topic of longstanding interest to both theorists and experimentalists at CoEPP.
The exotic particles in these models can also sometimes be used to achieve the grand unification of the strong, weak and electromagnetic interactions. This prospect was analysed by Schmidt and collaborators (JHEP 1609, 111). They delineated the cases where unification can be achieved, and where it is impossible.
Adrian Manning
In 2016, a strong focus of the theoretical research effort was on combining radiative neutrino mass generation with models of DM.
Research Kristian McDonald and collaborators examined the prospect of accommodating “minimal DM” in such models (Phys. Lett. B 757:399–404). This topic was independently also considered by Yi Cai and Michael Schmidt (JHEP 1605, 028). Minimal DM, in its original formation, is guaranteed to be stable because of its unusual quantum numbers under the SM gauge interactions. This feature becomes jeopardised when the extra physics for radiative neutrino mass
Kristian McDonald Michael A Schmidt Raymond Volkas
Students Jackson Clarke Joshua Ellis John Gargalionis
In ongoing work that will be completed in early 2017, Cai, Schmidt and Volkas have been working with PhD student John Gargalionis to examine an interesting possible connection between radiative neutrino mass models and certain experimental anomalies in the physics of B mesons. Returning to seesaw models, Cai and Volkas, working with PhD student Jackson Clarke and collaborator Yanagida (Institute for the Physics and Mathematics of the Universe, Japan), developed an E6-inspired scenario where the seesaw mass scale of new physics can be brought down to levels relevant for the LHC (Phys. Rev. D 94(3), 033003). This is interesting because, in the standard seesaw theories, the scale of new physics is inaccessible to the LHC. The detailed phenomenology of this model was examined in the MSc thesis by Joshua Ellis.
Figure 1 The E6-inspired pseudo-Dirac seesaw model provides potential explanations for the di-photon excess. The pseudo scalar pairs produced via s-channel singlet will decay to highly collimated (and displaced) photon pairs which will be reconstructed a single prompt photons.
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Precision tests of the Standard Model Researchers
Introduction
Kevin Finelli
The SM is the theory describing all known fundamental particles and their interactions through electromagnetic, weak, and colour forces. It assumed its current form in the mid-1970s and has achieved remarkable success by predicting the existence of weak gauge bosons, the top quark, the tau neutrino and, most recently, the Higgs boson.
Mark Kruse (Duke) Anthony Morley Peter Skands Kevin Varvell Jin Wang
Students Doug Davis (Duke) Carl Suster
With no evidence of physics beyond the SM in accelerator-based collider experiments, more attention is turning to both precision measurements of, and searches for, SM processes. This quest is motivated by the potential for new physics to perturb their rate and characteristics. Importantly, because they form the backgrounds to many searches, precise measurements of SM processes are an essential task of the LHC physics program. In 2016, two SM measurements were completed and have been submitted to, or been accepted by, highimpact physics journals; they are described below.
Tests of models of low energy QCD The measurement of the multiplicity and kinematic distributions of inclusive charged particles in proton– proton collisions provides insight into the strong interaction in the low energy, non-perturbative region of quantum chromodynamics (QCD). Particle interactions at these energy scales are typically described by QCD-inspired models implemented in
Figure 1 Charged particle distributions in pp interactions measured with the ATLAS detector at the LHC.
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Monte Carlo event generators with free parameters that can be constrained by such measurements. An accurate description of low energy, strong interaction processes is essential for simulating the effects of multiple proton–proton interactions at high instantaneous luminosity in hadron colliders. The importance of this measurement cannot be overstated because it forms the basis for all measurements undertaken at 13 TeV by elucidating the underlying event and the measurement of all systematic uncertainties arising in charged particle tracking. As convener of the ATLAS Minimum Bias@13 TeV task force, Anthony Morley led this measurement within ATLAS. Results were published in Physics Letters B (Phys. Lett. B 758, 67) and the European Physical Journal C (Eur. Phys. J. C 76, 502).
These measurements, together with previous results, shed light on the centre-of-mass energy dependence of charged particle multiplicities, which has been poorly constrained in the past. The distributions seen in Figure 1 are measured with tracks from charged particles, corrected for detector effects, and are presented as inclusive inelastic distributions. This measurement provides a direct test of the PYTHIA8 MONASH model pioneered by Peter Skands from the Monash node.
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AIDA at 13 TeV The An Inclusive Dilepton Analysis (AIDA) project includes the Sydney node and partner institute Duke University. AIDA is well established in CoEPP’s research program and in ATLAS. The first measurement made by the group, “Simultaneous measurements of the top-quark pair, W-boson pair, and Z boson decay to tau-pair production crosssections in pp collisions at collision energy 7 TeV with the ATLAS detector”, is the basis for current efforts. These efforts are advancing the AIDA technique to further improve the SM tests, including measuring the production of a single top quark in association with a W boson, which exploits Centre expertise in the study of single top-quark physics; and using differential cross-section measurements to extend the type of analysis reported in JHEP 06, 100 (2015), “Differential top-antitop cross-section measurements as a function of observables constructed from final-state particles using pp collisions at 7 TeV in the ATLAS detector”.
Single top-quark measurements at 13 TeV In collaboration with scientists from Bonn University, Kevin Finelli, Carl Suster and Jin Wang have made the first measurement of the production crosssection for a single top quark in association with a W boson at a collision energy of 13 TeV. This analysis was first presented at ICHEP 2016 in Chicago, United States, and a preliminary result has since been submitted to JHEP. Since October 2016, Finelli has served as convener for the single top-quark group in ATLAS, overseeing analysis activities and ensuring high-quality publications are prepared by the group.
Figure 2 Measurement of the cross-section for producing a W boson in association with a single top quark in pp collision energy 13 TeV with ATLAS.
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Dark matter Researchers
Introduction
Dark matter and unitarity
Peter Athron
The identity of DM, the mysterious substance that contributes most of the matter content of our universe, is one of the most longstanding and pressing problems in particle physics and cosmology. The energy density of DM in the universe is five times greater than that of ordinary matter, yet we have very little information about its fundamental properties. While many well-motivated particle physics theories predict a DM particle of some sort, the challenge is to identify which of these theories may be correct. Excitingly, we have reached an era where the sensitivity of current experiments is sufficient to substantially test one of the most popular and wellmotived classes of DM theories: weakly interacting massive particles, or WIMPs.
CoEPP theorists have made leading contributions to the development of self-consistent or physically well-behaved descriptions of DM interactions, with particular focus on the requirements of gauge invariance and perturbative unitarity.
Csaba Balázs Elisabetta Barberio Nicole Bell Giorgio Busoni Yi Cai Noel Dawe Matthew Dolan Robert Foot Paul Jackson Archil Kobakhidze Jinmian Li Tong Li Roman Nevzorov Anthony Thomas Francesca Ungaro Phillip Urquijo Raymond Volkas Martin White Anthony Williams Zhao-Huan Yu
Students Ankit Beniwal Amelia Brennan Jackson Clarke Ben Geytenbeek Dylan Harries Rebecca Leane David Long Millie McDonald Filip Rajec Andre Scaffidi Isaac Sanderson Sunny Vagnozzi
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CoEPP researchers have made a substantial contribution to DM research, including development of DM theories, phenomenological work on DM searches and signals, and analyses of ATLAS experimental data for mono-X and other DM signals.
Research Dark matter searches at the LHC CoEPP researchers made important contributions to collider DM research. CoEPP students Amelia Brennan and Mille McDonald worked with international collaborators Johanna Gramling and Thomas Jacques to determine constraints on DM simplified models using the LHC Run I dataset. Mono-jet, mono-Z (leptonic) and mono-W/Z (hadronic) channels were considered (JHEP 1605, 112). CoEPP postdoc Francesca Ungaro worked on the search for DM-associated production with bottom quarks, using 13 TeV proton–proton collisions at the ATLAS detector at the LHC (ATLAS-CONF-2016-086). Ungaro also searched for a supersymmetric partner of the top quark (in the jets plus mixing energy final state) in 13 TeV ATLAS data. This work also involved an interpretation of these results for the case of DM-associated production with top quarks (ATLASCONF-2016-077). Nicole Bell, Yi Cai and Rebecca Leane studied mono-W signals for DM production at the LHC in the context of self-consistent simplified models, and projected the future reach of the LHC for the leptonic (mono-lepton) and hadronic (mono fat jet) decays of the W boson. They also examined the ability of a weak isospin-violating effect to enhance signals, in models with underlying gauge invariance (JCAP 1601, 051).
Theorists at the Melbourne and Sydney nodes collaborated on a project related to unitarisation of effective field theory amplitudes for DM searches. Nicole Bell, Giorgio Busoni, Archil Kobakhidze, David Long and Michael Schmidt proposed a new approach to the LHC DM search analysis within the effective field theory framework by using the K-matrix unitarisation formalism. This approach allows a reasonable estimate of the DM production cross-section at high energies to be obtained, and hence reliable experimental bounds determined, without running unphysical effects such as perturbative unitarity violation. The LHC mono-jet process was used to illustrate this technique (JHEP 1608, 125). Bell, Cai and Leane studied indirect detection signals in a self-consistent hidden U(1) model, in which a DM candidate interacts with both a dark gauge boson, and a dark Higgs field. The dark Higgs provides a mass generation mechanism for the dark-sector field, and is required for the model to be physically well behaved to high energies. They found that the inclusion of two mediators opens up a new, dominant, s-wave annihilation channel that is missed in the usual single-mediator simplified model approach (JCAP 1608, 001). In a related work, Bell, Cai and Leane examined the impact of the dark-sector mass generation mechanism. They demonstrated that the DM interaction types, and hence the annihilation processes relevant for relic density and indirect detection, are strongly dictated by the mass generation mechanism chosen for the dark-sector particles, and the requirement of gauge invariance (to be published in JCAP in early 2017).
Dark matter model building CoEPP student Jackson Clarke worked with Raymond Volkas to propose a nonsupersymmetric technically natural model that accounts for neutrino masses, baryogenesis, the strong CP problem and DM. In this paper, DM is identified with the invisible axion in the context of a model that also explains neutrino masses and the matter–antimatter asymmetry of the universe in a technically natural way with respect to nongravitational interactions (Phys. Rev. D 93, 035001). Combining neutrino mass generation and a DM candidate in a unified model has always been
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Figure 1 Spin-1 mediated mono-W dark matter signal at the LHC.
intriguing. CoEPP researchers Cai and Schmidt revisited the class of RνMDM models, which incorporate minimal DM in radiative neutrino mass models based on the one-loop ultraviolet completions of the Weinberg operator (JHEP 1605, 028). Peter Athron, Dylan Harries, Roman Nevzorov and Anthony Williams explored the DM phenomenology of E6-inspired SUSY models that have an SM-like Higgs and evade current LHC limits on new states. These models allow striking new signatures that may be observable during Run 2 of the LHC, and can be substantially tested in future direct-detection experiments (Phys. Lett. B 760:19–25; JHEP 1612, 128). CoEPP students Ankit Beniwal and Filip Rajec – under the supervision of Martin White and Anthony Williams, plus international collaborators Christopher Savage, Pat Scott and Christoph Weniger – have performed the most comprehensive exploration to date of Higgs portal DM scenarios. These are arguably the simplest possible explanations of DM, in which one adds a single new particle to the SM, chooses a spin, and allows the new particle to interact only with the Higgs boson. The team studied three different DM spins in the framework of effective field theory, and applied all known constraints from particle and astrophysics experiments. They also studied future projections from forthcoming astrophysics experiments (Phys. Rev. D 93(11), 115016), including the Cherenkov Telescope Array (CTA), which Australia recently joined (including CoEPP members Csaba Balázs and Martin White). CoEPP postdoc Zhao-Huan Yu collaborated with Xiao-Jun Bi, Qian-Fei Xiang and Peng-Fei Yin on a project in which the 750 GeV diphoton excess observed at the LHC was linked with DM. The diphoton was explained in the framework of effective field theory, assuming the diphoton resonance is a scalar (pseudoscalar) particle. It was found that the large production rate and the broad width of this resonance are hard to simultaneously explain if only visible final states are considered. Therefore, an invisible decay channel to DM was strongly favoured by the diphoton excess with a broad width, given a large coupling of the new scalar to DM. By examining constraints on the parameter space of this scenario, it was found that DM searches can exclude a large portion of the parameter regions, accounting for the diphoton excess with a broad width (Nucl. Phys. B 909:43–64).
Yu collaborated with international colleague Tim Tait on a project involving triplet-quadruplet DM, in which the SM particle content was extended by one fermionic triplet and two fermionic quadruplets. This resulted in a minimal realistic ultraviolet-complete model of electroweak-interacting DM, in which the DM interacts with the Higgs doublet at tree level through two kinds of Yukawa couplings. The conditions under which the lightest new particle is neutral were examined, and the regions of parameter space for which the correct density is saturated were identified. While precision electroweak measurements, searches for DM scattering with nuclei, and DM annihilation place important constraints on this mode, they leave open a viable range for a thermal relic (JHEP 1603, 204). Yu also collaborated with Xiang, Bi and Yin on a simplified scenario in the NMSSM, in which only the singlino and higgsinos are light and other superpartners are decoupled. The future sensitivities of direct and indirect DM detection experiments were examined, together with LHC searches in the 3-lepton and 2-lepton channels (Phys. Rev. D 94, 055031).
Dark matter indirect detection Indirect searches for DM can be done by looking for the decay products of DM annihilation in distant astrophysical objects. In the case of DM decays to muons, a small correction to the photon flux arises from radiative muon decay, a rare but well understood decay mode of the muon. CoEPP student Andre Scaffidi, with Jinmian Li, Martin White, Anthony Williams and international collaborators Chris Savage and Katherine Freese, were the first to study this effect within a DM context, and studied the implications for both gamma ray and positron observations. The results have important implications for our understanding of the positron excess observed by the AMS-02 experiment (Phys. Rev. D 93, 115024). An excess of gamma rays coming from the galactic centre, and consistent with DM annihilation, has been previously observed by the Fermi-LAT experiment, exciting much interest in the particle physics community. However, 2016 was the year in which astrophysical explanations that do not require DM became increasingly convincing. Work by CoEPP member Martin White in collaboration with Roland Crocker and a number of other astrophysicists demonstrated that a mechanism that explains the
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generalised positron excess seen in our galaxy might also explain the Fermi gamma ray excess through the production of the millisecond pulsar population that is now the favoured astrophysical explanation (arXiv:1607.03495). Balázs and Tong Li examined the ability to extract DM properties from indirect detection data, using different interstellar emission scenarios proposed by the Fermi-LAT Collaboration to explain the Galactic Center gamma ray excess. They found that the properties of DM extracted from the data are highly sensitive to the modelling of the interstellar emission because of experimental and theoretical uncertainties (arXiv:1609.00113, submitted to JCAP). Balázs and Li also performed a comprehensive statistical analysis of the AMS-02 electron and positron fluxes, and the antiproton-to-proton ratio in the context of a simplified DM model. They found that AMS-02 observations are not only consistent with the DM hypothesis within the uncertainties, but that adding a DM contribution improves the fit to the data (JHEP 1605, 033). Balázs worked with the CTA collaboration to examine prospects for indirect detection with the CTA. In this work, sensitivity predictions for DM searches were given on various targets, taking into account the latest instrument response functions expected for the CTA and systematic uncertainties from the backgrounds. The conclusion was that, by observing the centre of the Galactic Halo, the CTA will have a unique chance of discovering weakly interacting massive particles with masses between a few hundred GeV and a few tens of TeV (PoS ICRC2015, 1203).
Astrophysical constraints on dark matter properties CoEPP student Ben Geytenbeek, under the supervision of Soumya Rao, Martin White and Anthony Williams, plus international
collaborators Pat Scott, Aldo Serenelli and Aaron Vincent, investigated the effects of DM with nontrival electromagnetic dipole moments on the structure of the solar interior. A range of helioseismology observables were used to derive new limits on electromagnetic dipole moment DM (arXiv:1610.06737). CoEPP theorist Robert Foot studied dissipate DM. This is where the self-interactions of DM particles are strong enough to have important astrophysical effects. Foot and past CoEPP MSc student Sunny Vagnozzi examined the missing satellite problem in the context of dissipative DM models. The suppression of small-scale structure arises in these models as a result of dark acoustic oscillations and dark diffusion damping at early times, just before the epoch of matter radiation equality. Such models can also potentially explain the puzzle of the planar distribution of satellite galaxies around the Milky Way and Andromeda (JCAP 1607, 013). Foot and PhD student Jackson Clarke studied novel implications of “plasma DM” for direct detection experiments. They pointed out that such DM can produce keV electron recoils observable in current experiments, and may possibly explain the longstanding DAMA annual modulation signal (JCAP 1601, 029). Foot examined the effect of dissipate DM on the rotation curves of dwarf galaxies and proposed a simple analytic formula for the DM density distribution around these galaxies. The analytic formula was motivated by dissipative DM dynamics, and was shown to provide a reasonably good fit to the rotation cure measurements of LITTLE THINGS (Local Irregulars That Trace Luminosity Extremes, The HI Nearby Galaxy Survey) dwarf galaxies (JCAP 1607, 011).
Figure 2 K-matrix unitarisation remedies the unphysical large enhancement of the monojet process in effective theories. All points on the red dashed Thales circle are mapped to the same point on the Argand circle.
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Searching for supersymmetry Introduction The SM describes all known particles and their interactions, and explains a vast number of experimental observations from subatomic collisions to the microscopic workings of the universe. The SM particle content was completed with the discovery of the Higgs boson. However, the presence of the Higgs particle also creates a serious problem. According to the SM, the mass of the Higgs boson is affected by physics that is separated from it by 15 orders of magnitude, thus creating a problem of “naturalness”. SUSY is an important theory in particle physics, which is being pursued in the hope of explaining such theoretical dilemmas. SUSY offers a simple solution to the naturalness problem by pairing all standard particles with superpartners. This mechanism, in turn, relies on known symmetries of the SM to shield the Higgs mass from high-energy corrections. SUSY also provides a DM candidate, currently lacking in the SM. It is a unified framework for all forces and matter, including gravity.
Research Theoretical models Archil Kobakhidze, Ning Liu, Lei Wu and collaborators have studied the phenomenology of closing the light stop (the supersymmetric partner to the top quark) available phase space in natural SUSY scenarios at the LHC (Phys. Lett. B 755, 76). Wu has further studied measurement of a singly produced stop to probe new physics (Phys. Rev. D 93(3), 035003). In a different environment, produced through the collision of high-energy electron and positron pairs, Wu and collaborators have looked at the phenomenology of SUSY effects in the production of Higgs bosons. This work will be an important input to future electron–positron machines such as the CERN Future Circular Collider (FCC-ee) or the proposed Circular Electron Positron Collider in China. Matthew Dolan and collaborators used simplified models as a useful way to characterise new physics scenarios for the LHC, and studied a variety of approaches to combine kinematic variables (JHEP 1608, 038). Dolan also worked on a likelihood analysis of SUSY SU(5) grand unification theory models, adding new constraints from searches for direct sparticle production at 13 TeV in the jets and missing transverse momentum final state – performed by CoEPP experimental collaborators – and in long-lived particle searches.
Sujeet Akula studied the variety of simplified models that are relevant in scenarios of supergravity grand unification, and studied the phenomenology at the LHC for Run 2 and in direct searches for neutralino DM (JHEP 1501, 158 [2015]).
Researchers
CoEPP researchers are studying models beyond minimal extensions to the SM arising from an elegant and unified picture at high energies, which are well motivated and have exciting consequences for low energy phenomenology. In an ongoing project, CoEPP researchers Peter Athron, Anthony Thomas, Sophie Underwood and Martin White are combining LHC measurements of the Higgs boson and mass limits on new supersymmetric particles for a complete search across parameter space for the E6SSM to identify scenarios compatible with Higgs properties, relic density, direct DM searches and beyond (arXiv:1611.05966).
Csaba Balázs
In other ongoing projects with related models, Athron, Dylan Harries and Anthony Williams have investigated fine-tuning in the E6SSM and other U(1) extensions of the minimal supersymmetric Standard Model (MSSM). Athron, Harries, Roman Nevzorov and Williams applied state-of-the-art techniques to calculate the relic density of DM, as well as the mass of the Higgs boson and new particles predicted by the model, and presented benchmark scenarios with phenomenology for future testing (Phys. Lett. B 760:19–25).
Pankaj Sharma
The same authors explored higgsino DM in a stringinspired model (JHEP 1612, 128), showing a large parameter space where it can naturally explain the measured relic density, but also demonstrated that the Large Underground Xenon (LUX) direct detection experiment has a large impact on scenarios with lighter phenomenology by heavily constraining welltempered neutralino DM proposed by Arkani-Hamed, Delgado and Giudice.
Damir Duvnjak
Athron and collaborators compared Higgs mass predictions of NMSSM spectrum generators, identifying the origin of the differences and demonstrating much larger uncertainties than had previously been assumed (Comput. Phys. Commun. 202, 113–130). Athron and collaborators also developed GM2Calc, which currently performs the most precise estimate of the anomalous magnetic moment of the muon in the MSSM (EPJC 76(2), 62), an “observable” where current measurements indicate evidence for physics beyond the SM that could be explained by SUSY.
Matthew Talia
Sujeet Akula Peter Athron Matthew Dolan Paul Jackson Archil Kobakhidze Lawrence Lee Jinmian Li Ning Liu Roman Nevzorov Andreas Petridis Anthony Thomas Francesca Ungaro Martin White Anthony Williams Lei Wu
Students Dylan Harries Jason Oliver Anum Qureshi Marco Santoni Abhishek Sharma Sophie Underwood Graham White
Athron further proposed and constructed a new method to calculate the Higgs mass in supersymmetric models (arXiv:1609.00371v3). He showed that this method leads to precise predictions both when the new physics scale is high and
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when it is very close to the electroweak scale. The calculation was implemented using FlexibleSUSY (also developed by Athron and collaborators) to make more precise predictions of Higgs masses in a number supersymmetric models and shed new light on the uncertainties in Higgs mass predictions in the minimal model. Jinmian Li and Williams investigated light NMSSM pseudoscalar states with boosted ditau tagging (JHEP 1605, 100). Pankaj Sharma and collaborators investigated the discovery prospects, through Higgs pair production with large missing transverse momentum at the LHC, of an R-parity violating SUSY model with a higgsino lightest supersymmetric particle, motivated by naturalness and the generation of neutrino masses (JHEP 1612, 062). Martin White is the co-leader of the GAMBIT collaboration, a statistical-fitting team with many international particle physicists, astrophysicists and statisticians, including a number of current CoEPP members (Athron, Balázs, Fowlie and Jackson). The GAMBIT code was completed during 2016, and the first version, with its accompanying publication, will be released soon.
Figure 1 A comparison of the observed and expected event yields as a function of signal region considered in the SUSY 0-lepton analysis using the recursive jigsaw reconstruction based search. The background expectations are those obtained from the background-only fits.
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Experimental searches CoEPP has played an active role in ATLAS SUSY searches. Jackson, with collaborators at Harvard University, has developed a new kinematic basis to design more natural, physics-inspired variables that permit more sensitive extraction of signals through a wide range of mass splittings. The method – recursive jigsaw reconstruction – has been pioneered by Adelaide CoEPP members, led by Jackson. The reconstruction code is now available for public use at Restframes.com. Jackson, Lee and Santoni presented the uses of the recursive jigsaw technique at the 2016 SUSY conference. This method has been applied to analyses within the ATLAS collaboration in searches for decays of top squarks and for gluino and light squark pair production in final states free of charged leptons. Considerable improvement in the region where the mass difference between parent and missing particle is small has been seen. Jackson, Lee, Petridis, Qureshi and Graham White contributed to the search for the pair production of gluinos and squarks resulting in final states enriched in hadronic jets and missing transverse momentum. Lee and Jackson spearheaded this analysis using the recursive jigsaw variables. They also led the group of 12 researchers from Australia, Europe and the United States throughout 2016.
ANNUAL REPORT
Petridis is the convener of the searches for SUSY with electroweakinos (the SUSY partners of the SM gauge bosons). He leads the ATLAS SUSY group in searches for final states with two and three leptons. The analyses pursued in this group focus on the production of electroweak SUSY partners or “gauginos”. Damir Duvnjak, Jackson, Petridis and Pankaj Sharma will publish a first analysis studying the trilepton final state, and dilepton production in association with jets and missing transverse momentum in the context of electroweak SUSY processes with intermediate W and Z bosons. The analysis has been able to be extended by using the recursive jigsaw reconstruction method.
Francesca Ungaro was involved in the search for top squarks in the 0-lepton final state. Her focus was to extend the SUSY search to probe generic models sensitive to SUSY and DM physics. Jackson and Santoni, with collaborator Christopher Rogan from Harvard, submitted the paper “Sparticles in motion” to Physical Review D. Santoni works with Sydney colleague Wu and former Sydney graduate student Jason Yu to study the phenomenology of compressed higgsino production, and design improved analysis variables and approaches to measuring new physics effects in the Higgs boson production channel in association with a top and anti-top quark pair.
Figure 2 Observed and expected exclusion limits on the common chargino and neutralino masses. The observed limits from ATLAS Run 1 are included for comparison. Current analyses pursued by Jackson and Petridis are targeting an as yet unprobed region in the two-lepton plot.
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Research computing Chief Investigators Martin Sevior Anthony Williams
Staff Lucien Boland, Research Computing Manager Goncalo Borges, Research Computing Officer Sean Crosby, Research Computing System Administrator and Developer Jeremy Hack, eResearch Developer
Introduction The field of research computing advances rapidly. The research computing (RC) team at CoEPP keeps abreast of innovations and developments in the field so that CoEPP researchers can achieve their scientific goals and maximise their participation within scientific collaborations. Increasing storage and computing power available to researchers is equally important and ensures that particle physics problems can be solved in a timely manner. The RC team manages operation of the Australian Worldwide LHC Computing Grid (WLCG) ATLAS Tier 2 site, as well as local computing resources. In 2016 the RC team grew CoEPP’s storage and compute capacity, delivered new computation services, including the MPI cluster, and procured a general purpose GPU cluster. The performance of the Australian ATLAS Tier 2 site in 2016 was remarkable, and saw it ranked first in the world.
Grid computing The WLCG provides researchers from around the world access to the LHC data and the computing resources necessary for their analyses. The WLCG is a global collaboration of more than 170 computing centres in 42 countries, and needs to be highly available and reliable to process the approximately 50 petabytes of LHC data generated each year.
In 2016, the Australian WLCG Tier 2 site was available for 99.74% of the year and had a reliability of 99.84%. This made it the highest ranked site of all ATLAS Tier 2 sites around the world and marked an incredible achievement by the RC team. The CoEPP Tier 2 cluster completed 105M HS06 CPU hours of computation, up 35% from 2015, and delivered an additional 5% above that pledged to the ATLAS distributed computing effort. This included many multi-core jobs, the successful completion of which required careful batch queue configuration and fine-tuning for efficient integration into CoEPP clusters.
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Australia-ATLAS Tier 2 grew by 280 terabytes to 1180 terabytes with the purchase of seven new storage servers, and by 800 HS06 to 11500 HS06 by dedicating spare nodes from the MPI cluster to CoEPP ATLAS Tier 2 queues, thereby meeting the experiment’s resource demands for 2016.
Infrastructure The RC team worked on many projects in 2016 to ensure that the capability of the core computing infrastructure reliably delivered the required computing services for ATLAS and CoEPP researchers. Key services were upgraded from Scientific Linux 6 to CentOS 7 in preparation for the eventual phasing out of the Scientific Linux distribution. This work provided a good opportunity to migrate from the XenServer virtualisation platform to the more integrated CentOS KVM solution, removing the need for the dedicated Xen storage network, and paving the way for easier and faster server deployments. The configuration management tool was upgraded from Puppet 3 to Puppet 4, and incorporated necessary CentOS 7 system changes. The Puppet software upgrade also allowed a change to the Git repository architecture so it would be more modular, and to redesign the Nagios monitoring infrastructure so it would be more flexible for additional service inclusions. The Ceph storage service was upgraded to the latest stable release and capacity was increased with the addition of the retired Tier 2 DPM storage nodes, giving a total of 306 terabyte raw capacity or 102 terabyte usable.
CoEPP local computing The RC team continued to provide reliable computing resources dedicated to local CoEPP researchers. The University of Sydney’s local storage server was replaced to provide in-warranty hardware for local home directories and data storage; and the University of Adelaide received a new server to increase their local cluster’s capabilities. The University of Melbourne received a new GPGPU cluster, partly funded by the School of Physics Pierce bequest and a collaboration with the Astronomy research group. This cluster will allow new and interesting machine learning techniques to be explored by researchers.
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Running and upgrading the experiment Being a member of the ATLAS collaboration provides the opportunity to not only analyse data from the experiment but to also run the experiment and perform R&D on upgrades. The ATLAS detector is arguably the most complex scientific instrument ever created, and, along with the WLCG that serves its data, requires many hundreds of people to run and maintain it. ATLAS recognises this through its organisation being loosely broken down into Detector Operation, Trigger, Computing and Software, Data Preparation, and Physics activities. With the LHC continually improving to reach and extend its design goals, the detector, trigger, computing infrastructure and software must not only be maintained, but must mirror the improvements in the LHC to simply keep up, and thereby ensure that physics outcomes are maximised. In this section, we highlight roles in running and upgrading the experiment undertaken by members of CoEPP. Roles associated with physics data analyses are covered in previous sections and are not included here. Roles undertaken by CoEPP members are: • ATLAS Beam Spot Coordinator Anthony Morley • ATLAS Fast Track Trigger Integration Pere Rados, Peter McNamara • ATLAS Fast Track Trigger offline software Thor Taylor, Noel Dawe, Elisabetta Barberio • ATLAS Trigger online operation Noel Dawe, Francesca Ungaro • ATLAS Fast Track Trigger upgrade electronics Takashi Kubota • ATLAS Fast Track Trigger online software and monitoring Takashi Kubota • ATLAS HLT development of hadronic multi-jet triggers using Razor variables Paul Jackson, Lawrence Lee
• ATLAS Semiconductor Tracker data acquisition upgrade Damir Duvnjak, Paul Jackson, Lawrence Lee, Mark Kruse (Duke) • ATLAS simulation development Andreas Petridis, Anum Qureshi • ATLAS Software Infrastructure Team Antonio Limosani • ATLAS tau lepton energy scale Daniele Zanzi, Brian Le • ATLAS tracking studies: “Stability study of ATLAS pixel cluster neural networks”, “Reconstruction in dense environments” Anthony Morley • ATLAS tau lepton trigger efficiency Federico Scutti, Lara Mason • ATLAS pile-up jet suppression studies Thu Lhe Pham, Francesca Ungaro • ATLAS Inner Tracker digitisation software development Jason Oliver, Paul Jackson, Martin White • ATLAS Fast Track Trigger implementation in HLT Jason Oliver, Paul Jackson • ATLAS Truth Tools harmonisation Anum Quereshi • ATLAS SCT read-out driver data acquisition calibration studies Damir Duvnjak, Paul Jackson • ATLAS Inner Tracker strip read-out studies Paul Jackson, Abhishek Sharma, Damir Duvnjak, Mark Kruse.
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Collaborations In addition to participation in large-scale collaborations, CoEPP researchers collaborate with individuals on specific research areas and projects. These collaborative relationships involve 234 researchers from over 130 universities and laboratories in 28 countries across Asia, Europe and the Americas. In 2016, CoEPP forged significant new relationships with major international facilities. These new relationships grow bilateral relations and ensure that Australia maintains a vibrant and flourishing research base.
Minister Hunt visits Fermilab Fermi National Accelerator Laboratory (Fermilab) is the major high-energy physics laboratory in the United States. In October, Fermilab and CoEPP signed an international Cooperative Research and Development Agreement (iCRADA) that encourages a rich and diverse collaboration between the institutions. The aim is to establish reciprocal visits by researchers, technical staff and students to collaborate on shared challenges. Potential shared activities include advanced theoretical physics, precision measurement techniques, advanced research computation methods, underground experimentation and accelerator R&D. CoEPP has a vigorous research program that aligns well with Fermilab’s. The signing of the iCRADA was commemorated with the visit to Fermilab by the Hon. Greg Hunt, Minister for Industry, Innovation and Science. Minister Hunt was joined in the visit by Mr Michael Wood, the Australian Consul-General in Chicago.
Minister Hunt was greatly impressed by his visit to Fermilab and expressed his strong support for high-energy physics in Australia. To further this he asked the US Department of Energy to invite Australia to participate in the Fermilab program. Since 1967, Fermilab has been working to answer fundamental questions about the universe and its origins. Scientists working at Fermilab discovered three fundamental particles – the top quark, the bottom quark and the tau neutrino – and the laboratory is gearing up to host the Deep Underground Neutrino Experiment (DUNE), the largest long-distance neutrino experiment in the world.“This is a welcome alliance between our two organisations,” said CoEPP Director Professor Geoffrey Taylor. “Whilst CoEPP is part of the ATLAS experiment at the LHC and Fermilab is the lead CMS laboratory in the US, there is a great deal that can be done on developing techniques, tools and detector technology beyond the confines of these experiments. Also, the underground laboratory experience of Fermilab with the DUNE project finds synergy with CoEPP developments at the new Stawell underground facility.”
Signing of the certificate commemorating the cooperation agreement between Fermilab and CoEPP. Left to right: Michael Wood (Australian Consul-General in Chicago), Hon. Greg Hunt (Minister for Industry, Innovation and Science), Professor Geoffrey Taylor (Director, CoEPP), Professor Marcela Carena (Head of Theoretical Physics Department and Director International Relations at Fermilab); Dr Nigel Lockyer (Director of Fermilab), Dr Mark Bollinger, (DOE Deputy Site Office Manager, Fermilab).
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“We’re glad to deepen our relationship with CoEPP as we move forward into a new era of physics research,” said Fermilab Director Nigel Lockyer.
Institute of High Energy Physics In November, IHEP in China and CoEPP signed a memorandum of understanding to establish scientific exchange, collaboration and cooperation between the two organisations. This agreement will see scientists share their expertise and collaborate on several activities for mutually beneficial outcomes. In particular, the planned Circular Electron Positron Collider provides enormous potential for collaborative activities between the two organisations. IHEP Director Professor Yifang Wang said, “Today we established the formal collaboration. It will benefit to the development of high energy physics in both countries, especially to the future large science facilities.” IHEP is China’s premier research institute in particle physics, astroparticle physics and accelerator science. It manages a number of China’s major scientific facilities, including the Beijing Electron Positron Collider, the Beijing Synchrotron Radiation Facility and the Daya Bay neutrino experiment. “This formalisation of a partnership with IHEP is a great step for Australia. We share a great many research interests and I look forward to many years of successful collaboration with our colleagues at IHEP,” said CoEPP Director Professor Geoffrey Taylor.
Minister Greg Hunt with Dr Nigel Lockyer inspecting the Linac Coherent Light Source II experiment at Fermilab.
Professor Geoffrey Taylor, Director of CoEPP and Professor Yifang Wang, Director of the Chinese Institute of High Energy Physics (IHEP) sign a memorandum of understanding to establish scientific exchange and collaboration.
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CONFERENCES AND WORKSHOPS In addition to organising its annual scientific workshop, in 2016 CoEPP co-organised some key international physics conferences.
ANNUAL REPORT
2016 CoEPP annual workshop and summer school in Torquay The CoEPP annual workshop was held in the Victorian seaside town of Torquay from 15 to 29 February. Approximately 150 people – a large proportion of Australia’s particle physics community – attended the combined gathering. In addition, CoEPP Partner Investigators from the University of Freiberg, the University of Cambridge, the University of Geneva, the University of Pennsylvania and Duke University attended, as well as visitors Voica Radescu (Ruprecht Karls University), Ulrich Parzefall (Albert Ludwigs University) and Tyler Corbett (Stony Brook), providing a truly international flavour to the gathering. As usual, the workshop covered topics in theoretical particle physics, experimental data analysis, instrumentation and the development of new facilities. The strong influence of astroparticle physics on modern particle physics was evident in presentations on the topics of DM searches, the universal baryon asymmetry and the precision measurement of the age of the universe. The influence of advanced statistical analysis on particle physics was covered in talks from the GAMBIT collaboration, which aims to provide tests of phenomenological models against constraints from global measurements in particle physics and astroparticle physics and
deep-neural nets. The latter technology is used by global software companies for artificial intelligence applications (e.g. natural voice interactions) and sophisticated data mining. Our applications of this technology for particle physics data analysis enable our researchers to take a leading role in the development of the next generation of data scientists. All the presentations were at the cutting edge of their respective topics, covering up-to-date research and developments. This was also reflected in the poster program, most notably by our graduate students, which showed a great variety of research at different levels of maturity. In addition to the strong scientific program, the event provided many opportunities for social interactions and networking. In particular, the surfing lessons and “team building activities” designed by Centre Manager David Varvel provided novel opportunities to get to know each other outside the usual academic environment. Overall, the workshop was a great success, and demonstrated the maturity of the Australian particle physics community.
Timeline of CoEPP conferences and workshops, 2016
26th International Conference on Nuclear Physics 2016
CoEPP Workshop Torquay, VIC
500+ scientists Adelaide, SA
150 scientists
JAN 2016
MAR
MAY
JUL
24 International Conference on Supersymmetry 2016 th
250 international speakers 500+ people Melbourne, VIC
SEP
JAN 2017
NOV
164 scientists
CosPA 2016
Sydney, NSW
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SUSY 2016 The Melbourne and Monash nodes hosted the 24th International Conference on Supersymmetry and Unification of Fundamental Interactions (SUSY16) in Melbourne during the first week of July. SUSY is one of the most prestigious annual meetings in theoretical particle physics, and CoEPP won the right to organise it from four other distinguished international institutes. This was the first time the conference was held in the southern hemisphere.
SUSY 2016 also saw a diverse range of talks representing many sectors of the vibrant theory community. The properties of the Higgs boson continue to be a strong motivational force, leading to new results in precision Higgs mass calculations in a variety of models and studies of the alignment limit. The absence of any signal from the LHC has also led to much work on “non-minimal” SUSY, which goes beyond the MSSM.
More than 250 eminent international speakers, academics, postdocs and students presented almost 300 talks at the conference. SUSY is held over 1 week, and is preceded by a 1-week graduate school attended by about 65 PhD-level students from all over the world.
The conference featured an art@CMS exhibit, curated by art@CMS and Australian Synchrotron artist Chris Henschke. Highlights included the world premiere of “Song of the Muons”, a “sonification” of CMS muon events by Henschke and physicist Wolfgang Adam. Professor John Ellis of King’s College London delivered a public lecture on “The dark frontier”, to an audience of 500.
Experimental results from LHC Run 2 were reported. Summaries from ATLAS and CMS on searches for supersymmetric particles confirmed no excesses in data recorded by the LHC at 13 TeV during 2015. These results have enabled the experiments to eclipse previous limits on supersymmetric particles set by data recorded at 8 TeV.
Delegates at the 2016 SUSY conference in Melbourne.
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CoEPP is grateful for support from the International Union of Pure and Applied Physics (IUPAP) for conference sponsorship.
ANNUAL REPORT
INPC 2016 The 26th International Conference on Nuclear Physics was held in Adelaide from 11 to 16 September. INPC is the major IUPAP class-A conference in nuclear physics, and it was an honour to host it in Australia for the first time. More than 500 scientists attended from all continents. Thanks to the sponsorship from several sources, including CoEPP, more than 50 students were offered free registration. The conference was opened by the Vice-President for Research at the University of Adelaide, Mike Brooks; the President of IUPAP, Bruce McKellar; and the Chair of C12, the IUPAP Commission on Nuclear Physics, Alinka Lepine-Szily. Bruce McKellar recalled aspects of the history of IUPAP and its Adelaide connection, with the first president, Nobel Laureate Sir William Henry Bragg, having served as the first Elder Professor of Physics at the University of Adelaide from 1886 to 1908. As usual, INPC covered all areas of nuclear physics, from structure to reactions, hadron physics, QCD, symmetries and relativistic heavy ions. The latest results across these areas were presented in more than 360 talks across 11 parallel sessions, organised by 23 conveners. Each session typically began with a 25-minute invited talk, followed by 15-minute presentations. In addition, two poster sessions were held, with refreshments to encourage participation. Plenary sessions held every morning included 27 invited plenary talks. For the first time in the history of INPC, the number of plenary invited speakers exceeded 40%. There were also three plenary presentations by the IUPAP prize winners in a very well-attended session on Wednesday morning. Details of the prize winners were reported in an earlier issue of Nuclear Physics News. This session was followed by the conference excursion, which offered the chance to meet Australian wildlife or sample local wines. While South Australia is officially the driest state on the driest continent, the excursions were made somewhat more memorable by more than 100 mm of rain, 20% of the annual rainfall! Turning to some of the scientific highlights, Kouji Morimoto outlined the very recent discovery of element 113 at RIKEN. Although the name is not yet final, it will likely be called nihonium, reflecting the country in which the discovery took place. In the field of nuclear structure, Sonia Bacca, from TRIUMF, described some frontiers in ab initio nuclear structure, while Witek Nazarewicz (Michigan State University) outlined his view of the prospects for breakthroughs in understanding nuclei. Shan-Gui Zhou (Institute of Theoretical Physics, Chinese Academy of Sciences) talked about the structure of exotic nuclei. Ann-Cecilie Larsen (University of Oslo) described novel techniques for constraining neutron capture rates relevant to heavyelement nucleosynthesis, and Rebecca Surman (University of Notre Dame) presented a nuclear physics solution to the puzzle of the r-process astrophysical site. Continuing the theme of nuclear science in astrophysics, Maria Lugaro (MTA Research Centre for Astronomy and Earth Sciences, Hungarian Academy of Sciences) took us along the path from cosmo-chronology to habitability.
With considerable interest in the issue of the symmetry energy of nuclear matter, Atsushi Tamii (Research Center for Nuclear Physics, Osaka University) explained how proton inelastic scattering might provide new information. With the insertion of hyperons to form hypernuclei now being recognised as an important field both in its own right and because of its relevance to neutron stars, the review of recent progress by Hiro Tamura (Tohoku) was very informative. Turning to reactions, Angela Bonaccorso (Istituto Nazionale di Fisica Nucleare, Pisa) and David Hinde (Australian National University) talked about the latest developments in their areas, with David focusing on the role of fission and fusion in the formation of heavy elements. Precision studies in nuclear systems provide an important method to search for physics beyond the SM, and Eric Norman (LBL) outlined the progress in double beta decay, focusing on CUORE (the cryogenic underground observatory for rare events). In addition, Gertrud Konrad (Stefan Meyer Institute) described the use of cold and ultra-cold neutrons as probes of new physics. Developments related to QCD, the fundamental theory of the strong force, were described by William Detmold (Massachusetts Institute of Technology), who explained the pioneering use of lattice QCD to calculate nuclear properties. Harvey Meyer (Johannes GutenbergUniversity, Mainz) also dealt with lattice QCD, but in the context of spectral functions and transport coefficients for heavy ion reactions. In the latter field, experimental developments were described by Camelia Mironov (MIT), ShinIchi Esumi (Tsukuba) and Tatyana Galatyuk (Technische Universität Darmstadt/GSI). Hadron physics was also well represented, with an outstanding overview of the current status of structure functions by Wally Melnitchouk (Jefferson Lab). On the experimental side, Silvia Niccolai (IPN Orsay) explained the status and future prospects for new information from the study of generalised parton distributions. Annalisa D’Angelo (Roma2) explained the recent developments in what might be termed conventional baryon spectroscopy, with a number of new states discovered in the last few years. Meanwhile, the host of apparently exotic states in charmed systems, the socalled X, Y and Z mesons, were presented by Shi-Lin Zhu of Peking University. While it was impossible to have reports on all the major new facilities, planned or constructed, in our field, the final session had presentations on three. Sidney Gales described the extreme light source initiative in Europe (at the Extreme Light Infrastructure – Nuclear Physics, Romania), and Abhay Deshpande explained plans in the United States to build an electron-ion collider to probe the quark and gluon structure of protons and nuclei. Finally, Sunchan Jeong from Korea outlined the plans and progress in relation to the ambitious new rare ion facility there. The project, called RISP, will lead to the construction of RAON, with superb capabilities to explore the limits of rare, short-lived atomic nuclei. Following the usual custom, C12 met on the Saturday before INPC 2016, hearing reports on previous conferences and considering applications for the future. Most significantly, C12 decides the location of the next INPC, and INPC 2019 will be held in Glasgow.
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On the Sunday, the IUPAP Working group on International Cooperation in Nuclear Physics held its annual meeting, with reports from around the world on the latest developments in nuclear science. With an eye to the social importance of nuclear science, Cynthia Keppel (JLab) presented an outstanding public lecture (sponsored by the Australian Institute for High Energy Physics) on hadron beam therapy on Tuesday evening. This was particularly timely because Australia has no hadron beam therapy centre, but hopes for up to four facilities in the near future.
Reports at and following the meeting suggest that INPC 2016 was extremely successful, with delegates appreciating not only the quality of the science but the experience of a very different country – physically and culturally – as well as the friendliness they encountered across the city of Adelaide. It is a pleasure to thank the conveners, whose tireless work contributed enormously to the success of the conference.
Above from left: Anthony Thomas (chair of INPC2016), Alinka Lépine-Szily – chair of the Commission for Nuclear Physics (C12), Bruce McKellar (president IUPAP), winners of the IUPAP Young Scientist Prize in Nuclear Physics: Haozhao Liang, Kara M. Lynch, Andreas Ekström, and past chair of C12 – Hideyuki Sakai. Image courtesy IUPAP Secretariat.
INTERNATIONAL NUCLEAR PHYSICS CONFERENCE ADELAIDE, AUSTRALIA ADELAIDE CONVENTION CENTRE 11-16 September 2016 www.inpc2016.com
Program Committee: Mahananda Dasgupta ANU Abhay Deshpande SUNY Andrew Stuchbery ANU Emiko Hiyama RIKEN Tohru Motobayashi RIKEN Anthony Thomas UofA Wolfram Weise ECT* Bing Song Zou CAS
Local Organising Committee: Michael Hotchkis ANSTO Derek Leinweber UofA Anthony Thomas UofA Anthony Williams UofA Ross Young UofA James Zanotti UofA
INPC 2016 poster.
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International Advisory Committee: Nicolas Alamanos CEA Saclay Thomas Aumann GSI & TU Darmstadt Faiçal Azaiez IN2P3 Jonathan Bagger TRIUMF Yorick Blumenfeld IN2P3 Angela Bracco Milano Stanley J. Brodsky Stanford Philippe Chomaz CEA-Saclay Jens Dilling TRIUMF Marco Durante GSI Rolf Ent Jefferson Laboratory Avraham Gal Jerusalem Sydney Galès CNRS Michel Garçon CEA-Saclay Konrad Gelbke Michigan Muhsin N. Harakeh Groningen Sotirios Harissopulos Demokritos Wick Haxton California-Berkeley David Hinde ANU Morten Hjorth-Jensen Michigan Dave Ireland Glasgow Rauno Julin Jyvaskyla
Ralf Kaiser Glasgow Taka Kajino Tokyo Reiner Kruecken TRIUMF Karlheinz Langanke Darmstadt Alinka Lépine-Szily Sao Paulo Bao-An Li Texas A&M Adam Maj Polish Academy of Sciences Wally Melnitchouk Jefferson Laboratory Dong-Pil Min Seoul Hugh Montgomery Jefferson Laboratory Tohru Motobayashi RIKEN Berndt Mueller Duke Witold Nazarewicz FRIB Thomas Nilsson Chalmers Yuri Oganessian JINR Alfredo Poves UAM Achim Richter Darmstadt Karsten Riisager AARHUS Marie-France Rivet IN2P3 Craig Roberts Argonne Guenther Rosner Glasgow Hiroyoshi Sakurai RIKEN Helmut Satz Bielefeld
Jurgen Schukraft CERN Yves Schutz CNRS, CERN John Simpson Daresbury Johanna Stachel Heidelberg Horst Stoecker Goethe Universitat Hans Stroeher FZ Jülich Michael Thoennessen Michigan Werner Tornow Duke Vladimir Tretyak Kiev Robert Tribble BNL Piet Van Duppen KU Leuven Willem van Oers Manitoba Dario Vretenar Zagreb Thomas Walcher Mainz Xin-Nian Wang LBL Wolfram Weise ECT* Eberhard Widmann Stefan Meyer Institut Michael Wiescher Notre Dame Bolek Wyslouch MIT Victor Zamfir ELI, Romania Fülöp Zsolt ATOMKI, Hungary
ANNUAL REPORT
CosPA 2016 The 13th International Symposium on Cosmology and Particle Astrophysics (CosPA 2016) was held in the new building of the Sydney Nanoscience Hub at the University of Sydney from 28 November to 2 December 2016. CoEPP, the NSW Chief Scientist’s Office and the Asia Pacific Center for Theoretical Physics (South Korea) were the major sponsors. The conference attracted 164 participants from 19 countries, and was the largest CosPA conference held. The scientific program included 29 invited plenary and more than 100 contributed parallel session talks. Topics included various aspects of particle astrophysics, DM and dark energy; cosmic microwave background radiation and large-scale structure; inflation and early universe cosmology; and gravity and gravitational waves.
As a part of the conference program and in collaboration with Sydney Ideas, Professor Manfred Lindner delivered a public talk, “Dark side of the universe”, on 29 November in the SNH Messel Lecture Theatre, which attracted an audience of 250 people. On 1 December, a joint meeting of the Asia Pacific CosPA Organisation Council and General Assembly confirmed Professor Raymond Volkas as the new President of the Council. The conference has been widely considered as a great success. An extract from Professor Yokoyama’s (former President of the Asia Pacific CosPA Council) letter says, “It was undoubtedly the best conference in the history of CosPA with many world-renowned speakers and good mixture of theory, observation, and experiments. Congratulations, and see you in Kyoto next year!”
The organisers made every effort to provide opportunities for young researchers from different countries to present their research at the conference, and strongly supported participation of female scientists.
Delegates at CosPA 2016, held in Sydney.
CosPA 2016 poster.
43 CONFERENCES AND WORKSHOPS
OUTREACH AND ENGAGEMENT Some highlights from the 2016 program are given in the next few pages.
ANNUAL REPORT
Global Physics Photowalk Exhibition On 25–26 September 2015, hundreds of amateur and professional photographers went behind the scenes at eight of the world’s leading physics laboratories. Australia participated for the first time, with the Stawell Underground Physics Laboratory (SUPL) allowing six photographers to take images of an underground physics laboratory in its early stages of development. Two submissions from SUPL were among the top photos in the competition categories. A permanent exhibition in Pioneer Lane in the heart of Stawell showcases winning entries, top photos from each participating lab and images taken during the SUPL Photowalk. The exhibition was launched in August 2016 by Dr Phillip Urquijo with help from local high-school students.
“Symmetries” – art@CMS “Symmetries” was the Australian premiere exhibition of works from art@CMS. It was held from 3 to 8 July at the University of Melbourne as part of the 24th International Conference on Supersymmetry and Unification of Fundamental Interactions (SUSY 2016). Curated by art@CMS artist Chris Henschke, “Symmetries” featured artworks by Michael Hoch, Alessandro Catocci and Pierluigi Paolucci, and Yuki Shiraishi and John Ellis. It also included the premiere presentation of a CMS data sonification installation by Chris Henschke and experimental physicist Wolfgang Adam.
Collider exhibition and Sydney Science Festival
Museum, and takes visitors on an immersive journey through the LHC at CERN’s Geneva laboratories. CoEPP worked closely with museum curators to augment the exhibition with Australian content. This included parts of the ATLAS detector that were built at the University of Melbourne, information and content regarding the development of SUPL, and the loan of a portable muon counter for use in talks. In addition to Collider, the Powerhouse hosted the Sydney Science Festival from 11 to 21 August. As part of the program, CoEPP partnered with the museum to offer a 2-day workshop where participants built a 1:50 scale model of the ATLAS detector using LEGO®, alongside the model’s creator Dr Sascha Mehlhase, particle physicist and lecturer at Ludwig-Maximilians University Munich. There was also the opportunity for festival participants to build LHC “micro models” with LEGO®. The micro models were designed by Nathan Readioff from the University of Liverpool, and included LHC Magnets, the CMS Detector, the ALICE Detector, the ATLAS Detector and the LHCb Detector.
Public lectures CoEPP researchers and visitors gave several free public lectures and school talks during the year. Selected highlights include: • a public lecture by British theoretical physicist Professor John Ellis CBE FRS – “The dark frontier” • a talk to 50 year 4 and 6 students at Sunshine Harvester Primary School by David Wakeham • a talk to 400 students from years 9 and 10, and Victorian Certificate of Education physics students from Stawell and surrounding high schools by Dr Phillip Urquijo – “Searching for dark matter at the Stawell Underground Physics Laboratory”.
The Museum of Applied Arts and Sciences hosted the Collider exhibition at the Powerhouse Museum in Sydney from 11 August to 30 October 2016. Collider was developed at the London Science
45 OUTREACH AND ENGAGEMENT
ARC CENTRE OF EXCELLENCE FOR PARTICLE PHYSICS AT THE TERASCALE
John Gargalionis speaks at work experience week
46 OUTREACH AND ENGAGEMENT
ANNUAL REPORT
High schools program
Exhibitions
The high schools program delivers opportunities for young people to engage in, and develop their passion for, physical sciences at key decision-making times in their study lives.
CoEPP had a strong year in terms of visual art exhibitions. It hosted three separate exhibitions (including one for permanent display), and worked closely with the Powerhouse Museum to augment the Collider exhibition with appropriate Australian content.
Work experience week Year 10 students are immersed in a week-long program of tutorials, lectures and laboratory sessions. Sessions included lectures on particle physics, distributed computing and the WLCG, the SM and DM. The week is based at the Melbourne node and run concurrently with other science streams. In 2016, the schedule included sessions run by the Faculty of Science and a tour of the data centre at Queensberry Street that houses the Australian-ATLAS Tier 2 centre. All participants develop research posters that are presented at the end of the week. CoEPP organisers and participants were Nicole Bell, Innes Bigaram, Lucien Boland, Giorgio Busoni, Tyler Corbett and Justin Tan.
Collision exhibition In partnership with RiAus, selected entries from the 2015 Collision competition were exhibited as part of the 2016 Visual Arts program of the Adelaide Fringe Festival. The exhibition was grouped into sections highlighting the diverse range of national entries, which included school students from Elonera Montessori School, New South Wales; artists from across Australia; a family based in Tasmania; and an astrophysicist from Ballarat. In addition to artworks, selected multimedia from CERN and the ATLAS Lego model were exhibited. The exhibition ran from 8 February to 15Â March at the FutureSpace Gallery in Adelaide.
Particle physics masterclass The masterclass is an annual calendar highlight. First offered in 2012, students attend a day-long event of lectures and tutorials on the LHC and the SM; laboratory sessions where they analyse real ATLAS experiment data; and an ATLAS virtual visit, where participants link up with scientists at CERN, are taken on a tour of the ATLAS control room and are given the opportunity to ask questions about the largest experiment on Earth. In 2016, CoEPP ran an offsite masterclass held at South Oakleigh Secondary College. CoEPP participants were Noel Dawe, Shanette De La Motte, Johnathan Gargalionis and Cate MacQueen.
A virtual visit to CERN for the particle physics masterclass.
47 OUTREACH AND ENGAGEMENT
PUBLICATIONS
ANNUAL REPORT
Refereed journal articles A Ahriche, KL McDonald, S Nasri and I Picek, “A critical analysis of one-loop neutrino mass models with minimal dark matter”, Phys. Lett. B 757:399–404 (2016). Y Cai and MA Schmidt, “Revisiting the RνMDM models”, JHEP 1605, 028 (2016). A Ahriche, KL McDonald and S Nasri, “The scale-invariant scotogenic model”, JHEP 1606, 182 (2016). A Ahriche, A Manning, KL McDonald and S Nasri, “Scale-invariant models with one-loop neutrino mass and dark matter candidates”, Phys. Rev. D 94(5), 053005 (2016). C Hagedorn, T Ohlsson, S Riad and MA Schmidt, “Unification of gauge couplings in radiative neutrino mass models”, JHEP 1609, 111 (2016). Y Cai, JD Clarke, RR Volkas and TT Yanagida, “TeV-scale pseudoDirac seesaw mechanisms in an E6-inspired model”, Phys. Rev. D 94(3), 033003 (2016). BHJ McKellar, “Dipole phases – topological and useful”, The Universe 4(3):4–18 (2016).
L Cheng and G Valencia, “Two Higgs doublet models augmented by a scalar colour octet”, JHEP 1609, 079 (2016). A Hayreter, X-G He and G Valencia, “Yukawa sector for lepton flavor violating in h → μτ and CP violation in h → ττ”, Phys. Rev. D 94(7), 075002 (2016). MJ Dolan, M Spannowsky, Q Wang and Z-H Yu, “Determining the quantum numbers of simplified models in ttX production at the LHC”, Phys. Rev. D 94(1), 015025 (2016). NF Bell, Y Cai and RK Leane, “Dark forces in the sky: signals from Z’ and the dark Higgs”, JCAP 1608(08), 001 (2016). S Mrenna and P Skands, “Automated parton-shower variations in Pythia 8”, Phys. Rev. D 94(7), 074005 (2016). AW Thomas and JD Vergados, “Solar neutrinos as background in dark matter searches involving electron detection”, J. Phys. G 43, 07LT01 (2016). N Fischer, S Prestel, M Ritzmann and P Skands, “Vincia for hadron colliders”, Eur. Phys. J. C 76(11), 589 (2016).
RR Volkas, “Physics without force: the quantum world and topology”, The Universe 4(3):19–27 (2016).
SD Rindani, P Sharma and A Shivaji, “Unraveling the CP phase of top-Higgs coupling in associated production at the LHC”, Phys. Lett. B 761:25–30 (2016).
F Poignant, S Penfold, J Asp, P Takhar and P Jackson, “GEANT4 simulation of cyclotron radioisotope production in a solid target”, Phys. Med. 32:728–734 (2016).
BM Dillon, DP George and KL McDonald, “Regarding the radion in Randall–Sundrum models with brane curvature”, Phys. Rev. D 94(6), 064045 (2016).
P Athron, D Harries, R Nevzorov and AG Williams, “Dark matter in a constrained E6 inspired SUSY model”, JHEP 1612, 128 (2016).
T Cohen, MJ Dolan, S El Hedri, J Hirschauer, N Tran and A Whitbeck, “Dissecting jets and missing energy searches using n-body extended simplified models”, JHEP 1608, 038 (2016).
J Li, R Patrick, P Sharma and AG Williams, “Boosting the charged Higgs search prospects using jet substructure at the LHC”, JHEP 1611, 164 (2016). S Akula, C Balázs and GA White, “Semi-analytic techniques for calculating bubble wall profiles”, Eur. Phys. J. C 76(12), 681 (2016). L Wu, B Yang and M Zhang, “Little Higgs dark matter after PandaXII/LUX 2016 and LHC Run-1”, JHEP 1612, 152 (2016). A Kobakhidze, C Lagger and A Manning, “Constraining noncommutative spacetime from GW150914”, Phys. Rev. D 94(6), 064033 (2016). J Dragos, R Horsley, W Kamleh, DB Leinweber, Y Nakamura, PEL Rakow, G Schierholz, RD Young and JM Zanotti, “Nucleon matrix elements using the variational method in lattice QCD”, Phys. Rev. D 94(7), 074505 (2016). DL Whittenbury, ME Carrillo-Serrano and AW Thomas, “Quark– meson coupling model based upon the Nambu–Jona Lasinio model”, Phys. Lett. B 762:467–472 (2016). N Bell, G Busoni, A Kobakhidze, DM Long and MA Schmidt, “Unitarisation of EFT amplitudes for dark matter searches at the LHC”, JHEP 1608, 125 (2016). Q-F Xiang, X-J Bi, P-F Yin and Z-H Yu, “Searching for singlinohiggsino dark matter in the NMSSM”, Phys. Rev. D 94(5), 055031 (2016).
R Foot and J Gargalionis, “Explaining the 750 GeV diphoton excess with a colored scalar charged under a new confining gauge interaction”, Phys Rev. D 94(1), 011703 (2016). E Conte, B Fuks, J Guo, J Li and AG Williams, “Investigating light NMSSM pseudoscalar states with boosted ditau tagging”, JHEP 1605, 100 (2016). S Moretti, R Santos and P Sharma, “Optimising charged Higgs boson searches at the Large Hadron Collider across bbW ± final states”, Phys. Lett. B 760:697–705 (2016). PTP Hutauruk, IC Cloët and AW Thomas, “Flavor dependence of the pion and kaon form factors and parton distribution functions”, Phys. Rev. C 94(3), 035201 (2016). S Biswas, EJ Chun and P Sharma, “Di-Higgs signatures from R-parity violating supersymmetry as the origin of neutrino mass”, JHEP 1612, 062 (2016). A Scaffidi, K Freese, J Li, C Savage, M White and AG Williams, “Gamma rays from muons from WIMPs: implementation of radiative muon decays for dark matter analyses”, Phys. Rev. D 93(11), 115024 (2016). W Bentz, A Kotzinian, HH Matevosyan, Y Ninomiya, AW Thomas and K Yazaki, “Quark-jet model for transverse momentum dependent fragmentation functions”, Phys. Rev. D 94(3), 034004 (2016). A Hayreter, X-G He and G Valencia, “CP violation in h → ττ and LFV h → μτ”, Phys. Lett. B 760:175–177 (2016).
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ARC CENTRE OF EXCELLENCE FOR PARTICLE PHYSICS AT THE TERASCALE
T Martin, P Skands and S Farrington, “Probing collective effects in hadronisation with the extremes of the underlying event”, Eur. Phys. J. C 76(5), 299 (2016).
P Athron, D Harries, R Nevzorov, AG Williams, “E6 inspired SUSY benchmarks, dark matter relic density and a 125 GeV Higgs”, Phys. Lett. B 760:19–25 (2016).
ME Carrillo-Serrano, W Bentz, IC Cloët and AW Thomas, “Baryon octet electromagnetic form factors in a confining NJL model”, Phys. Lett. B 759:178–183 (2016).
X-J Bi, Q-F Xiang, P-F Yin and Z-H Yu, “The 750 GeV diphoton excess at the LHC and dark matter constraints”, Nucl. Phys. B 909:43–64 (2016).
A Fowlie and MH Bardsley, “Superplot: a graphical interface for plotting and analysing MultiNest output”, Eur. Phys. J. Plus 131(11), 391 (2016).
F Wang, L Wu, JM Yang and M Zhang, “750 GeV diphoton resonance, 125 GeV Higgs and muon g − 2 anomaly in deflected anomaly mediation SUSY breaking scenarios”, Phys. Lett. B 759:191–199 (2016).
XG Wang, C-R Ji, W Melnitchouk, Y Salamu, AW Thomas and P Wang, “Constraints on s − s asymmetry of the proton in chiral effective theory”, Phys. Lett. B 762:52–56 (2016). F Staub, P Athron, L Basso, MD Goodsell, D Harries, ME Krauss, K Nickel, T Opferkuch, L Ubaldi, A Vicente and Alexander Voigt, “Precision tools and models to narrow in on the 750 GeV diphoton resonance”, Eur. Phys. J. C 76(9), 516 (2016). ND Barrie, A Kobakhidze and S Liang, “Natural inflation with hidden scale invariance”, Phys. Lett. B 756, 390–393 (2016). A Fowlie, C Balázs, G White, L Marzola and M Raidal, “Naturalness of the relaxion mechanism”, JHEP 1608, 100 (2016). R Foot and S Vagnozzi, “Solving the small-scale structure puzzles with dissipative dark matter”, JCAP 1607(07), 013 (2016). ND Barrie, A Kobakhidze, M Talia and L Wu, “750 GeV composite axion as the LHC diphoton resonance”, Phys. Lett. B 755:343–347 (2016). JR Stone, PAM Guichon, PG Reinhard and AW Thomas, “Finite nuclei in the quark-meson coupling model”, Phys. Rev. Lett. 116(9), 092501 (2016). C-W Chiang, X-G He and G Valencia, “Z′ model for b → sℓ l¯ flavor anomalies”, Phys. Rev. D 93(7), 074003 (2016). SF King and R Nevzorov, “750 GeV diphoton resonance from singlets in an exceptional supersymmetric standard model”, JHEP 1603, 139 (2016). MJ Dolan, JL Hewett, M Krämer and TG Rizzo, “Simplified models for Higgs physics: singlet scalar and vector-like quark phenomenology”, JHEP 1607, 039 (2016). JD Vergados, FT Avignone, M Kortelainen, P Pirinen, PC Srivastava, J Suhonen and AW Thomas, “Inelastic WIMP-nucleus scattering to the first excited state in 125Te”, J. Phys. G 43(11), 115002 (2016). TMP Tait and Z-H Yu, “Triplet-quadruplet dark matter”, JHEP 1603, 204 (2016). X-F Han, L Wang, L Wu, JM Yang and M Zhang, “Explaining 750 GeV diphoton excess from top/bottom partner cascade decay in twoHiggs-doublet model extension”, Phys. Lett. B 756:309–316 (2016). A Kobakhidze, L Wu and J Yue, “Electroweak baryogenesis with anomalous Higgs couplings”, JHEP 1604, 011 (2016). C Cai, Z-H Yu and H-H Zhang, “750 GeV diphoton resonance as a singlet scalar in an extra dimensional model”, Phys. Rev. D 93(7), 075033 (2016). KM Patel and P Sharma, “Interpreting 750 GeV diphoton excess in SU(5) grand unified theory”, Phys. Lett. B 757:282–288 (2016).
50 PUBLICATIONS
JD Clarke and R Foot, “Plasma dark matter direct detection”, JCAP 1601(01), 029 (2016). A Beniwal, F Rajec, C Savage, P Scott, C Weniger, M White and AG Williams, “Combined analysis of effective Higgs portal dark matter models”, Phys. Rev. D 93(11), 115016 (2016). A Kobakhidze, F Wang, L Wu, JM Yang and M Zhang, “750 GeV diphoton resonance in a top and bottom seesaw model”, Phys. Lett. B 757:92–96 (2016). XG Wang, AW Thomas and RD Young, “Electromagnetic contribution to charge symmetry violation in parton distributions”, Phys. Lett. B 753:595–599 (2016). N Mehrtens, AK Romer, RC Nichol, CA Collins, M Sahlén, PJ Rooney, JA Mayers, A Bermeo-Hernandez, M Bristow, D Capozzi, L Christodoulou, J Comparat, M Hilton, B Hoyle, ST Kay, AR Liddle, RG Mann, K Masters, CJ Miller, JK Parejko, F Prada, AJ Ross, DP Schneider JP Stott, A Streblyanska, PTP Viana, M White, H Wilcox and I Zehavi, “The XMM Cluster Survey: the halo occupation number of BOSS galaxies in X-ray clusters”, Mon. Not. Roy. Astron. Soc. 463(2):1929–1943 (2016). H Li, P Wang, DB Leinweber and AW Thomas, “Spin of the proton in chiral effective field theory”, Phys. Rev. C 93(4), 045203 (2016). J Bellm, S Gieseke, D Grellscheid, S Plätzer, M Rauch, C Reuschle, P Richardson, P Schichtel, MH Seymour, A Siódmok, A Wilcock, N Fischer, MA Harrendorf, G Nail, A Papaefstathiou, D Rauch, “Herwig 7.0/Herwig++ 3.0 release note”, Eur. Phys. J. C 76(4), 196 (2016). P Cox, AD Medina, TS Ray and A Spray, “Novel collider and dark matter phenomenology of a top-philic Z′”, JHEP 1606, 110 (2016). NF Bell, Y Cai and RK Leane, “Mono-W dark matter signals at the LHC: simplified model analysis”, JCAP 1601(01), 051 (2016). Z-W Liu, W Kamleh, DB Leinweber, FM Stokes, AW Thomas and J-J Wu, “Hamiltonian effective field theory study of the N∗ (1535) resonance in lattice QCD”, Phys. Rev. Lett. 116(8), 082004 (2016). Y Cai and AP Spray, “The galactic center excess from ℤ 3 scalar semi-annihilations”, JHEP 1606, 156 (2016). DL Whittenbury, HH Matevosyan and AW Thomas, “Hybrid stars using the quark-meson coupling and proper-time Nambu–JonaLasinio models”, Phys. Rev. C 93(3), 035807 (2016). FP Huang, P-H Gu, P-F Yin, Z-H Yu and X Zhang, “Testing the electroweak phase transition and electroweak baryogenesis at the LHC and a circular electron-positron collider”, Phys. Rev. D 93(10), 103515 (2016). A Kobakhidze, N Liu, L Wu, JM Yang and M Zhang, “Closing up a light stop window in natural SUSY at LHC”, Phys. Lett. B 755:76–81 (2016).
ANNUAL REPORT
A Hayreter, G Valencia, “T-odd correlations from the top-quark chromoelectric dipole moment in lepton plus jets top-pair events”, Phys. Rev. D 93(1), 014020 (2016).
A Kobakhidze, A Manning and A Tureanu, “Observable Zitterbewegung in curved spacetimes,” Phys. Lett. B 757:84–91 (2016).
P Athron, M Bach, HG Fargnoli, C Gnendiger, R Greifenhagen, J Park, S Paßehr, D Stöckinger, H Stöckinger-Kim and A Voigt, “GM2Calc: precise MSSM prediction for (g – 2) of the muon”, Eur. Phys. J. C 76(2), 62 (2016).
J Li and AG Williams, “Tau reconstruction methods at an electronpositron collider in the search for new physics”, Phys. Rev. D 93(7), 075019 (2016).
J Barnard, P Cox, T Gherghetta and A Spray, “Long-lived, colourtriplet scalars from unnaturalness”, JHEP 1603, 003 (2016). GA White, “General analytic methods for solving coupled transport equations: from cosmology to beyond”, Phys. Rev. D 93(4), 043504 (2016). Y Cai and MA Schmidt, “A case study of the sensitivity to LFV operators with precision measurements and the LHC”, JHEP 1602, 176 (2016). Y Cai and AP Spray, “Fermionic semi-annihilating dark matter”, JHEP 1601, 087 (2016). JD Clarke and RR Volkas, “Technically natural nonsupersymmetric model of neutrino masses, baryogenesis, the strong CP problem, and dark matter”, Phys. Rev. D 93(3), 035001 (2016). C Balázs and T Li, “AMS-02 fits dark matter”, JHEP 1605, 033 (2016). R Horsley, Y Nakamura, H Perlt, D Pleiter, PEL Rakow, G Schierholz, A Schiller, R Stokes, H Stüben, RD Young and JM Zanotti, for the QCDSF and UKQCD collaborations, “QED effects in the pseudoscalar meson sector”, JHEP 1604, 093 (2016). N Liu, L Wu, B Yang and M Zhang, “Single top partner production in the Higgs to diphoton channel in the Littlest Higgs Model with T-parity”, Phys. Lett. B 753:664–669 (2016). R Horsley, Y Nakamura, H Perlt, D Pleiter, PEL Rakow, G Schierholz, A Schiller, R Stokes, H Stüben, RD Young and JM Zanotti, “Isospin splittings of meson and baryon masses from three-flavor lattice QCD + QED”, J. Phys. G 43(10), 10LT02 (2016).
A Ahriche, KL McDonald and S Nasri, “A radiative model for the weak scale and neutrino mass via dark matter”, JHEP 1602, 038 (2016). F Staub, P Athron, U Ellwanger, R Gröber, M Mühlleitner, P Slavich and A Voigt, “Higgs mass predictions of public NMSSM spectrum generators”, Comput. Phys. Commun. 202:113–130 (2016). IC Cloët, W Bentz and AW Thomas, “Relativistic and nuclear medium effects on the Coulomb sum rule”, Phys. Rev. Lett. 116(3), 032701 (2016). J Li and AW Thomas, “Bottom quark contribution to spin-dependent dark matter detection”, Nucl. Phys. B 906:60–76 (2016). R Foot, “Dissipative dark matter and the rotation curves of dwarf galaxies”, JCAP 1607(07), 011 (2016). K Hikasa, J Li, L Wu and JM Yang, “Single top squark production as a probe of natural supersymmetry at the LHC”, Phys. Rev. D 93(3), 035003 (2016). NL Hall, PG Blunden, W Melnitchouk, AW Thomas and RD Young, “Quark–hadron duality constraints on γZ box corrections to parityviolating elastic scattering”, Phys. Lett. B 753:221–226 (2016). K Huitu, K Rao, SD Rindani and P Sharma, “Effective fermion-Higgs interactions at an e+e− collider with polarized beams”, Nucl. Phys. B 911:274–294 (2016). J Cao, C Han, J Ren, L Wu, JM Yang and Y Zhang, “SUSY effects in Higgs productions at high energy e+e− colliders”, Chin. Phys. C 40(11), 113104 (2016).
ATLAS collaboration ATLAS authors from CoEPP are Elisabetta Barberio, Curtis Black, Amelia Brennan, Noel Dawe, Kevin Finelli, Paul Jackson, David Jennens, Takashi Kubota, Brian Le, Lawrence Lee, Tony Limosani, Millie McDonald, Peter McNamara, Marco Milesi, Anthony Morley, Francesco Nuti, Andreas Petridis, Pere Rados, Mark Scarcella, Federico Scutti, Laurence Spiller, Carl Suster, Geoffrey Taylor, Thor Taylor, Francesca Ungaro, Phillip Urquijo, Kevin Varvell, Jin Wang, Martin White, Bruce Yabsley and Daniele Zanzi. “The laser calibration of the Atlas Tile Calorimeter during the LHC Run 1”, JINST 11(10), T10005 (2016).
“A measurement of material in the ATLAS tracker using secondary hadronic interactions in 7 TeV pp collisions”, JINST 11(11), P11020 (2016). – “Luminosity determination in pp collisions at √s = 8 TeV using the ATLAS detector at the LHC”, Eur. Phys. J. C 76(12), 653 (2016).
“Search for dark matter produced in association with a hadronically – decaying vector boson in pp collisions at √s = 13 TeV with the ATLAS detector”, Phys. Lett. B 763:251–268 (2016).
“Measurement of W+W− production in association with one jet in – proton–proton collisions at √s = 8 TeV with the ATLAS detector”, Phys. Lett. B 763:114–133 (2016).
“Study of hard double-parton scattering in four-jet events in pp – collisions at √s = 7 TeV with the ATLAS experiment”, JHEP 1611, 110 (2016).
51 PUBLICATIONS
ARC CENTRE OF EXCELLENCE FOR PARTICLE PHYSICS AT THE TERASCALE
“Search for minimal supersymmetric Standard Model Higgs bosons H/A and for a Z′ boson in the ττ final state produced in pp collisions – at √s = 13 TeV with the ATLAS detector,” Eur. Phys. J. C 76(11), 585 (2016). “Dark matter interpretations of ATLAS searches for the electroweak – production of supersymmetric particles in √s = 8 TeV proton–proton collisions”, JHEP 1609, 175 (2016). “Measurement of the bb¯ dijet cross section in pp collisions at – √s = 7 TeV with the ATLAS detector”, Eur. Phys. J. C 76(12), 670 (2016). “Search for new phenomena in different-flavour high-mass dilepton – final states in pp collisions at √s = 13 Tev with the ATLAS detector”, Eur. Phys. J. C 76(10), 541 (2016). “Measurement of top quark pair differential cross-sections in the – dilepton channel in pp collisions at √s = 7 and 8 TeV with ATLAS”, Phys. Rev. D 94(9), 092003 (2016). “Measurement of the total cross section from elastic scattering in – pp collisions at √s = 8 TeV with the ATLAS detector”, Phys. Lett. B 761:158–178 (2016). “Search for squarks and gluinos in events with hadronically decaying tau leptons, jets and missing transverse momentum in proton– – proton collisions at √s = 13 TeV recorded with the ATLAS detector”, Eur. Phys. J. C 76, 683 (2016). “Measurement of exclusive γγ → W+W− production and search – for exclusive Higgs boson production in pp collisions at √s = 8 TeV using the ATLAS detector”, Phys. Rev. D 94(3), 032011 (2016). “Search for high-mass new phenomena in the dilepton final state – using proton–proton collisions at √s = 13 TeV with the ATLAS detector”, Phys. Lett. B 761:372–392 (2016). “Search for Higgs and Z boson decays to ϕγ with the ATLAS detector”, Phys. Rev. Lett. 117(11), 111802 (2016). “Measurement of jet activity in top quark events using the eμ final – state with two b-tagged jets in pp collisions at √s = 8 TeV with the ATLAS detector”, JHEP 1609, 074 (2016). “Search for supersymmetry in a final state containing two photons – and missing transverse momentum in √s = 13 TeV pp collisions at the LHC using the ATLAS detector”, Eur. Phys. J. C 76(9), 517 (2016).
“The ATLAS data acquisition and high level trigger system”, JINST 11(6), P06008 (2016). “Measurement of the W±Z boson pair-production cross section in – pp collisions at √s = 13 TeV with the ATLAS detector”, Phys. Lett. B 762:1–22 (2016). “Search for new resonances in events with one lepton and missing – transverse momentum in pp collisions at √s = 13 TeV with the ATLAS detector”, Phys. Lett. B 762:334–352 (2016). “Search for top squarks in final states with one isolated lepton, jets, – and missing transverse momentum in √s = 13 TeV pp collisions with the ATLAS detector”, Phys. Rev. D 94(5), 052009 (2016). – “Search for resonances in diphoton events at √s = 13 TeV with the ATLAS detector”, JHEP 1609, 001 (2016). “Measurement of the tt¯ production cross-section using eμ events – with b-tagged jets in pp collisions at √s = 13 TeV with the ATLAS detector”, Phys. Lett. B 761:136–157 (2016). “Measurement of the inelastic proton–proton cross section at –
√s = 13 TeV with the ATLAS detector at the LHC”, Phys. Rev. Lett.
117(18), 182002 (2016).
“Measurements of the Higgs boson production and decay rates and constraints on its couplings from a combined ATLAS and CMS – analysis of the LHC pp collision data at √s = 7 and 8 TeV”, JHEP 1608, 045 (2016). “Search for TeV-scale gravity signatures in high-mass final states – with leptons and jets with the ATLAS detector at √s = 13 TeV”, Phys. Lett. B 760:520–537 (2016). “Search for the Standard Model Higgs boson produced by vector– boson fusion and decaying to bottom quarks in √s = 8 TeV pp collisions with the ATLAS detector”, JHEP 1611, 112 (2016). “Measurement of the top quark mass in the tt¯ → dilepton channel – from √s = 8 TeV ATLAS data”, Phys. Lett. B 761:350–371 (2016). “Measurement of the photon identification efficiencies with the ATLAS detector using LHC Run-1 data”, Eur. Phys. J. C 76(12), 666 (2016). “Measurement of the double-differential high-mass Drell-Yan cross – section in pp collisions at √s = 8 TeV with the ATLAS detector”, JHEP 1608, 009 (2016).
“Search for bottom squark pair production in proton–proton – collisions at √s = 13 TeV with the ATLAS detector”, Eur. Phys. J. C 76(10), 547 (2016).
√s = 13 TeV pp interactions measured with the ATLAS detector at
“Search for the Higgs boson produced in association with a W boson and decaying to four b-quarks via two spin-zero particles in pp collisions at 13 TeV with the ATLAS detector”, Eur. Phys. J. C 76(11), 605 (2016).
“Measurement of the angular coefficients in Z-boson events using – electron and muon pairs from data taken at √s = 8 TeV with the ATLAS detector”, JHEP 1608, 159 (2016).
“The performance of the jet trigger for the ATLAS detector during 2011 data taking”, Eur. Phys. J. C 76(10), 526 (2016). “Search for heavy long-lived charged R-hadrons with the ATLAS – detector in 3.2 fb−1 of proton–proton collision data at √s = 13 TeV”, Phys. Lett. B 760:647–665 (2016). “Searches for heavy diboson resonances in pp collisions at –
√s = 13 TeV with the ATLAS detector”, JHEP 1609, 173 (2016).
“Search for pair production of Higgs bosons in the bb¯bb¯ final state – using proton–proton collisions at √s = 13 TeV with the ATLAS detector”, Phys. Rev. D 94(5), 052002 (2016).
52 PUBLICATIONS
“Charged-particle distributions at low transverse momentum in – the LHC”, Eur. Phys. J. C 76(9), 502 (2016).
“Search for pair production of gluinos decaying via stop and sbottom in events with b-jets and large missing transverse momentum in – pp collisions at √s = 13 TeV with the ATLAS detector”, Phys. Rev. D 94(3), 032003 (2016). “Measurement of the relative width difference of the B0-B̅ 0 system with the ATLAS detector”, JHEP 1606, 081 (2016). “Transverse momentum, rapidity, and centrality dependence of –— – inclusive charged-particle production in √s NN = 5.02 TeV p + Pb collisions measured by the ATLAS experiment”, Phys. Lett. B 763:313–336 (2016).
ANNUAL REPORT
– “Search for scalar leptoquarks in pp collisions at √s = 13 TeV with the ATLAS experiment”, New J. Phys. 18(9), 093016 (2016). “Search for gluinos in events with an isolated lepton, jets and – missing transverse momentum at √s = 13 Te V with the ATLAS detector”, Eur. Phys. J. C 76(10), 565 (2016). “Search for squarks and gluinos in final states with jets and missing – transverse momentum at √s = 13 TeV with the ATLAS detector”, Eur. Phys. J. C 76(7), 392 (2016). “Measurement of the inclusive isolated prompt photon cross section – in pp collisions at √s = 8 TeV with the ATLAS detector”, JHEP 1608, 005 (2016). “Search for new phenomena in final states with an energetic jet and – large missing transverse momentum in pp collisions at √s = 13 TeV using the ATLAS detector”, Phys. Rev. D 94(3), 032005 (2016). “Measurements of the charge asymmetry in top-quark pair – production in the dilepton final state at √s = 8 TeV with the ATLAS detector”, Phys. Rev. D 94(3), 032006 (2016).
– “Charged-particle distributions in pp interactions at √s = 8 TeV measured with the ATLAS detector”, Eur. Phys. J. C 76(7), 403 (2016). “Measurements of W±Z production cross sections in pp collisions at – √s = 8 TeV with the ATLAS detector and limits on anomalous gauge boson self-couplings”, Phys. Rev. D 93(9), 092004 (2016). “Measurement of total and differential W+W− production cross – sections in proton–proton collisions at √s = 8 TeV with the ATLAS detector and limits on anomalous triple-gauge-boson couplings”, JHEP 1609, 029 (2016). – “Search for supersymmetry at √s = 13 TeV in final states with jets and two same-sign leptons or three leptons with the ATLAS detector”, Eur. Phys. J. C 76(5), 259 (2016). “Measurement of event-shape observables in Z → ℓ +ℓ – events – in pp collisions at √s = 7 TeV with the ATLAS detector at the LHC”, Eur. Phys. J. C 76(7), 375 (2016).
√s = 8 TeV with the ATLAS detector”, Phys. Rev. D 93(11),
“Search for new phenomena in final states with large jet multiplicities and missing transverse momentum with ATLAS using – √s = 13 TeV proton–proton collisions”, Phys. Lett. B 757:334–355 (2016).
“Study of the rare decays of B s0 and B 0 into muon pairs from data collected during the LHC Run 1 with the ATLAS detector”, Eur. Phys. J. C 76(9), 513 (2016).
“Search for single production of a vector-like quark via a heavy gluon in the 4b final state with the ATLAS detector in pp collisions at – √s = 8 TeV”, Phys. Lett. B 758:249–268 (2016).
“Measurements of Zγ and Zγγ production in pp collisions at – 112002 (2016).
“Search for the Standard Model Higgs boson decaying into bb¯ produced in association with top quarks decaying hadronically in pp – collisions at √s = 8 TeV with the ATLAS detector”, JHEP 1605, 160 (2016). “Measurement of fiducial differential cross sections of gluon-fusion production of Higgs bosons decaying to WW∗ → eνμν with the – ATLAS detector at √s = 8 TeV”, JHEP 1608, 104 (2016). “Search for new phenomena in events with a photon and missing – transverse momentum in pp collisions at √s = 13 TeV with the ATLAS detector”, JHEP 1606, 059 (2016). “Measurement of W± and Z-boson production cross sections in pp – collisions at √s = 13 TeV with the ATLAS detector”, Phys. Lett. B 759:601–621 (2016). “Search for charged Higgs bosons produced in association with a top quark and decaying via H± → τν using pp collision data – recorded at √s = 13 TeV by the ATLAS detector”, Phys. Lett. B 759:555–574 (2016). “Beam-induced and cosmic-ray backgrounds observed in the ATLAS detector during the LHC 2012 proton–proton running period”, JINST 11(5), P05013 (2016). “Search for resonances in the mass distribution of jet pairs with one or two jets identified as b-jets in proton–proton – collisions at √s = 13 TeV with the ATLAS detector”, Phys. Lett. B 759:229–246 (2016). “Muon reconstruction performance of the ATLAS detector in – proton–proton collision data at √s = 13 TeV”, Eur. Phys. J. C 76(5), 292 (2016). “Identification of high transverse momentum top quarks in pp – collisions at √s = 8 TeV with the ATLAS detector”, JHEP 1606, 093 (2016).
“Search for single production of vector-like quarks decaying into Wb – in pp collisions at √s = 8 TeV with the ATLAS detector”, Eur. Phys. J. C 76(8), 442 (2016). “Test of CP invariance in vector-boson fusion production of the Higgs boson using the optimal observable method in the ditau decay channel with the ATLAS detector”, Eur. Phys. J. C 76(12), 658 (2016). – “Charged-particle distributions in √s = 13 TeV pp interactions measured with the ATLAS detector at the LHC”, Phys. Lett. B 758:67–88 (2016). “Measurement of the charged-particle multiplicity inside jets from –
√s = 8 TeV pp collisions with the ATLAS detector”, Eur. Phys. J. C
76(6), 322 (2016).
“A search for top squarks with R-parity-violating decays to all– hadronic final states with the ATLAS detector in √s = 8 TeV proton– proton collisions”, JHEP 1606, 067 (2016). “A search for an excited muon decaying to a muon and two jets in – pp collisions at √s = 8 TeV with the ATLAS detector”, New J. Phys. 18(7), 073021 (2016). “Probing lepton flavour violation via neutrinoless τ ⟶ 3μ decays with the ATLAS detector”, Eur. Phys. J. C 76(5), 232 (2016). “Measurement of the CP-violating phase ϕ s and the Bs0 meson decay width difference with Bs0 → J/ψϕ decays in ATLAS”, JHEP 1608, 147 (2016). “Measurement of the charge asymmetry in highly boosted top-quark – pair production in √s = 8 TeV pp collision data collected by the ATLAS experiment”, Phys. Lett. B 756:52–71 (2016). “Reconstruction of hadronic decay products of tau leptons with the ATLAS experiment”, Eur. Phys. J. C 76(5), 295 (2016).
53 PUBLICATIONS
ARC CENTRE OF EXCELLENCE FOR PARTICLE PHYSICS AT THE TERASCALE
“Search for new phenomena with photon+jet events in – proton–proton collisions at √s = 13 TeV with the ATLAS detector”, JHEP 1603, 041 (2016).
“Identification of boosted, hadronically decaying W bosons and – comparisons with ATLAS data taken at √s = 8 TeV”, Eur. Phys. J. C 76(3), 154 (2016).
“Measurement of the ZZ production cross section in pp collisions at –
“Performance of pile-up mitigation techniques for jets in pp – collisions at √s = 8 TeV using the ATLAS detector”, Eur. Phys. J. C 76(11), 581 (2016).
√s = 13 TeV with the ATLAS detector”, Phys. Rev. Lett. 116(10), 101801
(2016).
“Combination of searches for WW, WZ, and ZZ resonances in – pp collisions at √s = 8 TeV with the ATLAS detector”, Phys. Lett. B 755:285–305 (2016). “Search for charged Higgs bosons in the H± → tb decay channel in – pp collisions at √s = 8 TeV using the ATLAS detector”, JHEP 1603, 127 (2016). “Measurement of the differential cross-sections of prompt and – non-prompt production of J/ψ and ψ(2S) in pp collisions at √s = 7 and 8 TeV with the ATLAS detector”, Eur. Phys. J. C 76(5), 283 (2016). ∗±
“Measurement of D , D± and D±s meson production cross sections in – pp collisions at √s = 7 TeV with the ATLAS detector”, Nucl. Phys. B 907:717–763 (2016). “Search for strong gravity in multijet final states produced in pp – collisions at √s = 13 TeV using the ATLAS detector at the LHC”, JHEP 1603, 026 (2016). “Measurement of the transverse momentum and ϕ ∗η distributions of – Drell–Yan lepton pairs in proton–proton collisions at √s = 8 TeV with the ATLAS detector”, Eur. Phys. J. C 76(5), 291 (2016). “Search for new phenomena in dijet mass and angular distributions – from pp collisions at √s = 13 TeV with the ATLAS detector”, Phys. Lett. B 754:302–322 (2016). “Performance of b-jet identification in the ATLAS experiment”, JINST 11(4), P04008 (2016). “Measurement of the dependence of transverse energy production at large pseudorapidity on the hard-scattering kinematics of – proton–proton collisions at √s = 2.76 TeV with ATLAS”, Phys. Lett. B 756:10–28 (2016). “Search for the Standard Model Higgs boson produced in association with a vector boson and decaying into a tau pair in pp collisions – at √s = 8 TeV with the ATLAS detector”, Phys. Rev. D 93(9), 092005 (2016). “Evidence for single top-quark production in the s-channel in – proton–proton collisions at √s = 8 TeV with the ATLAS detector using the matrix element method”, Phys. Lett. B 756:228–246 (2016). – “A search for prompt lepton-jets in pp collisions at √s = 8 TeV with the ATLAS detector”, JHEP 1602, 062 (2016). “Measurements of top-quark pair differential cross-sections in the – lepton+jets channel in pp collisions at √s = 8 TeV using the ATLAS detector”, Eur. Phys. J. C 76(10), 538 (2016). – “Dijet production in √s = 7 TeV pp collisions with large rapidity gaps at the ATLAS experiment”, Phys. Lett. B 754:214–234 (2016). “Measurement of the correlations between the polar angles of – leptons from top quark decays in the helicity basis at √s = 7 TeV using the ATLAS detector”, Phys. Rev. D 93(1), 012002 (2016). “Search for dark matter produced in association with a Higgs boson – decaying to two bottom quarks in pp collisions at √s = 8 TeV with the ATLAS detector”, Phys. Rev. D 93(7), 072007 (2016).
54 PUBLICATIONS
“Measurement of the differential cross-section of highly boosted top – quarks as a function of their transverse momentum in √s = 8 TeV proton–proton collisions using the ATLAS detector”, Phys. Rev. D 93(3), 032009 (2016). “Search for anomalous couplings in the Wtb vertex from the measurement of double differential angular decay rates of single top quarks produced in the t-channel with the ATLAS detector”, JHEP 1604, 023 (2016). “Measurement of the production cross-section of a single top quark in association with a W boson at 8 TeV with the ATLAS experiment”, JHEP 1601, 064 (2016). “Search for the production of single vector-like and excited quarks – in the Wt final state in pp collisions at √s = 8 TeV with the ATLAS detector”, JHEP 1602, 110 (2016). “Search for magnetic monopoles and stable particles with high electric charges in 8 TeV pp collisions with the ATLAS detector”, Phys. Rev. D 93(5), 052009 (2016). “Measurements of four-lepton production in pp collisions – at √s = 8 TeV with the ATLAS detector”, Phys. Lett. B 753:552–572 (2016). “Search for the electroweak production of supersymmetric particles – in √s = 8 TeV pp collisions with the ATLAS detector”, Phys. Rev. D 93(5), 052002 (2016). – “Measurement of jet charge in dijet events from √s = 8 TeV pp collisions with the ATLAS detector”, Phys. Rev. D 93(5), 052003 (2016). “Search for new phenomena in events with at least three photons – collected in pp collisions at √s = 8 TeV with the ATLAS detector”, Eur. Phys. J. C 76(4), 210 (2016). “Search for direct top squark pair production in final states with two – tau leptons in pp collisions at √s = 8 TeV with the ATLAS detector”, Eur. Phys. J. C 76(2), 81 (2016). “A new method to distinguish hadronically decaying boosted Z bosons from W bosons using the ATLAS detector”, Eur. Phys. J. C 76(5), 238 (2016). – “Observation of long-range elliptic azimuthal anisotropies in √s = 13 and 2.76 TeV pp collisions with the ATLAS detector”, Phys. Rev. Lett. 116(1)7, 172301 (2016). “Measurement of the charge asymmetry in top-quark pair production in the lepton-plus-jets final state in pp collision data at – √s = 8 TeV with the ATLAS detector”, Eur. Phys. J. C 76(2), 87 (2016). “Search for a high-mass Higgs boson decaying to a W boson pair – in pp collisions at √s = 8 TeV with the ATLAS detector”, JHEP 1601, 032 (2016). “Search for single top-quark production via flavour-changing neutral currents at 8 TeV with the ATLAS detector”, Eur. Phys. J. C 76(2), 55 (2016).
ANNUAL REPORT
“Search for invisible decays of a Higgs boson using vector-boson – fusion in pp collisions at √s = 8 TeV with the ATLAS detector”, JHEP 1601, 172 (2016).
“Search for an additional, heavy Higgs boson in the H → ZZ decay – channel at √s= 8 TeV in pp collision data with the ATLAS detector”, Eur. Phys. J. C 76(1), 45 (2016).
“Measurements of fiducial cross-sections for tt¯ production with one – or two additional b-jets in pp collisions at √s = 8 TeV using the ATLAS detector”, Eur. Phys. J. C 76(1), 11 (2016).
“Measurements of the Higgs boson production and decay rates and – coupling strengths using pp collision data at √s = 7 and 8 TeV in the ATLAS experiment”, Eur. Phys. J. C 76(1), 6 (2016).
“Search for flavour-changing neutral current top-quark decays to qZ in pp collision data collected with the ATLAS detector at – √s = 8 TeV”, Eur. Phys. J. C 76(1), 12 (2016). – “Searches for scalar leptoquarks in pp collisions at √s = 8 TeV with the ATLAS detector”, Eur. Phys. J. C 76(1), 5 (2016).
“ATLAS Run 1 searches for direct pair production of third-generation squarks at the Large Hadron Collider”, Eur. Phys. J. C 75(10), 510 (2015); erratum: Eur. Phys. J. C 76(3), 153 (2016).
“Constraints on non-Standard Model Higgs boson interactions in an effective Lagrangian using differential cross sections measured in – the H → γγ decay channel at √s = 8 TeV with the ATLAS detector”, Phys. Lett. B 753:69–85 (2016). “Measurement of the centrality dependence of the charged-particle pseudorapidity distribution in proton–lead collisions at –— – √s N N = 5.02 TeV with the ATLAS detector”, Eur. Phys. J. C 76(4), 199 (2016). “Study of the B +c → J/ψD+s and B +c → J/ψD∗ +s decays with the ATLAS detector”, Eur. Phys. J. C 76(1), 4 (2016).
“Centrality, rapidity and transverse momentum dependence of isolated prompt photon production in lead–lead collisions at –— – √s N N = 2.76 TeV measured with the ATLAS detector”, Phys. Rev. C 93(3), 034914 (2016). “Study of the spin and parity of the Higgs boson in diboson decays with the ATLAS detector”, Eur. Phys. J. C 75(10), 476 (2015); erratum: Eur. Phys. J. C 76(3), 152 (2016). “Search for massive supersymmetric particles decaying to many jets – using the ATLAS detector in pp collisions at √s = 8 TeV”, Phys. Rev. D 91(11), 112016 (2015); erratum: Phys. Rev. D 93(3), 039901 (2016). “Measurement of the tt¯ production cross-section using eμ events – with b-tagged jets in pp collisions at √s = 7 and 8 TeV with the ATLAS detector”, Eur. Phys. J. C 74(10), 3109 (2014); addendum: Eur. Phys. J. C 76(11), 642 (2016).
Belle collaboration Belle authors from CoEPP are Elisabetta Barberio, Giacomo Caria, Chia-Ling Hsu, Chunhua Li, Luis Pesantez, Martin Sevior, Francesco Tenchini, Phillip Urquijo, Kevin Varvell, Eiasha Waheed and Bruce Yabsley.
“Search for a dark vector gauge boson decaying to π+π− using η → π+π−γ decays”, Phys. Rev. D 94(9), 092006 (2016).
“First observation of doubly Cabibbo-suppressed decay of a charmed baryon: Λ +c → pK+π−”, Phys. Rev. Lett. 117(1), 011801 (2016).
“Measurement of the branching ratio of B̅ 0 → D∗ +τ −ν τ relative to B̅ 0 → D∗ +ℓ−ν ℓ decays with a semileptonic tagging method”, Phys. Rev. D 94(7), 072007 (2016).
“First observation of the decay B0 → ψ(2S)π0”, Phys. Rev. D 93(3), 031101 (2016).
“Study of excited Ξ c states decaying into Ξ 0c and Ξ +c baryons”, Phys. Rev. D 94(5), 052011 (2016).
“Search for the rare decay D0 → γγ at Belle”, Phys. Rev. D 93(5), 051102 (2016).
“Measurement of the CKM angle φ 1 in B0 → D¯(∗ )0h0, D¯0→K0Sπ+π− decays with time-dependent binned Dalitz plot analysis”, Phys. Rev. D 94(5), 052004 (2016). “Studies of charmed strange baryons in the ΛD final state at Belle”, Phys. Rev. D 94(3), 032002 (2016). “Search for a massive invisible particle X0 in B+ → e+X0 and B+ → μ +X0 decays”, Phys. Rev. D 94(1), 012003 (2016). “Search for XYZ states in Υ(1S)) inclusive decays”, Phys. Rev. D 93(11), 112013 (2016). “First observation of γγ → pp¯K+K− and search for exotic baryons in pK systems”, Phys. Rev. D 93(11), 112017 (2016). “Search for the decay B0 → ϕγ”, Phys. Rev. D 93(11), 111101 (2016). “Observation of Zb(10610) and Zb(10650) decaying to B mesons”, Phys. Rev. Lett. 116(21), 212001 (2016).
“Inclusive and exclusive measurements of B decays to χ c1 and χ c2 at Belle”, Phys. Rev. D 93(5), 052016 (2016). “Observation of the decay B0s→ K¯ 0K¯ 0”, Phys. Rev. Lett. 116(16), 161801 (2016). “Measurement of the decay B → Dℓν ℓ in fully reconstructed events and determination of the Cabibbo-Kobayashi-Maskawa matrix element |Vcb|”, Phys. Rev. D 93(3), 032006 (2016). “Study of B0 → ρ +ρ − decays and implications for the CKM angle ϕ 2”, Phys. Rev. D 93(3), 032010; addendum: Phys. Rev. D 94(9), 099903 (2016). “Measurement of D0– D¯0 mixing and search for CP violation in D0 → K+K−, π+π− decays with the full Belle data set”, Phys. Lett. B 753:412–418 (2016). “Search for B0 → π−τ +ν τ with hadronic tagging at Belle”, Phys. Rev. D 93(3), 032007 (2016).
55 PUBLICATIONS
ARC CENTRE OF EXCELLENCE FOR PARTICLE PHYSICS AT THE TERASCALE
“First model-independent Dalitz analysis of B0 → DK∗ 0, D→K 0S π+π− decay”, PTEP 2016(4), 043C01 (2016). “Study of π0 pair production in single-tag two-photon collisions”, Phys. Rev. D 93(3), 032003 (2016).
“Energy scan of the e+e− → hb(nP)π+π−(n = 1,2) cross sections and evidence for Υ(11020) decays into charged bottomonium-like states”, Phys. Rev. Lett. 117(14), 142001 (2016).
“Measurements of the Υ(10860) and Υ(11020) resonances via σ(e+e− → Υ(nS)π+π−)”, Phys. Rev. D 93(1), 011101 (2016). “Measurement of the lepton forward-backward asymmetry in B → Xsℓ +ℓ − decays with a sum of exclusive modes”, Phys. Rev. D 93(3), 032008(2016); addendum: Phys. Rev. D 93(5), 059901 (2016).
CDF collaboration CDF author from CoEPP is Antonio Limosani. “Measurement of the WW and WZ production cross section using final states with a charged lepton and heavy-flavor jets in the full CDF Run II data set”, Phys. Rev. D 94(3), 032008 (2016).
“Search for a low-mass neutral Higgs boson with suppressed couplings to fermions using events with multiphoton final states”, Phys. Rev. D 93(11), 112010 (2016).
∗ + − “Measurement of sin2θ lept eff using e e pairs from γ /Z bosons produced in pp¯ collisions at a center-of-momentum energy of 1.96 TeV”, Phys. Rev. D 93(11), 112016 (2016).
“Measurement of vector boson plus D∗ (2010)+ meson production in – pp¯ collisions at √s = 1.96 TeV”, Phys. Rev. D 93(5), 052012 (2016).
“Measurement of the forward–backward asymmetry of top-quark and antiquark pairs using the full CDF Run II data set”, Phys. Rev. D 93(11), 112005 (2016). “Measurement of the forward–backward asymmetry in low-mass bottom-quark pairs produced in proton–antiproton collisions”, Phys. Rev. D 93(11), 112003 (2016). “Measurement of the B± production cross section in pp¯ collisions at –
c
√s = 1.96 TeV”, Phys. Rev. D 93(5), 052001 (2016).
Books GA White, A pedagogical introduction to electroweak baryogenesis, Morgan & Claypool Publishers, San Rafael, California, 2016.
56 PUBLICATIONS
“Updated measurement of the single top quark production cross section and |Vtb| in the missing transverse energy plus jets topology – in pp¯ collisions at √s = 1.96 TeV”, Phys. Rev. D 93(3), 032011 (2016). “Measurement of the inclusive leptonic asymmetry in top-quark pairs that decay to two charged leptons at CDF”, Phys. Rev. Lett. 113, 042001 (2014); erratum: Phys. Rev. Lett. 117(19), 199901 (2016). “Measurement of the leptonic asymmetry in tt¯ events produced in – pp¯ collisions at √s = 1.96 TeV”, Phys. Rev. D 88(7), 072003 (2013); erratum: Phys. Rev. D 94(9), 099901 (2016).
ANNUAL REPORT
Refereed conference proceedings S Moretti, R Santos and P Sharma, “Charged Higgs boson searches at the LHC via multiple bbW± final states”, arXiv 1611.09082 [hep-ph] (2016).
N Fischer and P Skands, “Coherent showers for the LHC”, arXiv 1604.04805 [hep-ph] (2016).
P Skands and D d’Enterria, “QCD and γγ studies at FCC-ee”, PoS ICHEP2016 1156, arXiv 1610.06254 [hep-ph] (2016).
W Kamleh, JMM Hall, DB Leinweber, BJ Menadue, BJ Owen, AW Thomas and RD Young, “The lambda (1405) is a KN molecule”, PoS CD15, 037 (2016).
O Oliveira, A Kızılersü, PJ Silva, J-I Skullerud, A Sternbeck and AG Williams, “Lattice landau gauge quark propagator and the quark–gluon vertex”, Acta Phys. Polon. Supp. 9:363–368 (2016).
P Athron, M Műhlleitner, R Nevzorov and AG Williams, “Exotic Higgs decays in U(1) extensions of the MSSM”, arXiv 1602.04453 [hep-ph] (2016).
P Skands, N Fischer, S Prestel and M Ritzmann, “The VINCIA antenna shower for hadron colliders”, arXiv 1609.07205 [hep-ph] (2016).
C Reuschle, J Bellm, S Gieseke, D Grellscheid, S Plätzer, M Rauch, P Richardson, P Schichtel, MH Seymour, A Siódmok, A Wilcock, N Fischer, MA Harrendorf, G Nail, A Papaefstathiou and D Rauch, “NLO efforts in Herwig++”, arXiv 1601.04101 [hep-ph] (2016).
MJ Dolan, J Hewett, M Krämer and TG Rizzo, “Simplify your life: towards more model-independent new physics searches”, PoS DIS2016 008 (2016). R Nevzorov and AW Thomas, “E6 inspired composite Higgs model and 750 GeV diphoton excess”, EPJ Web Conf. 125, 02021, arXiv 1608.00320 [hep-ph] (2016). A Kobakhidze, L Wu and J Yue, “Electroweak baryogenesis with anomalous Higgs couplings”, Int. J. Mod. Phys. Conf. Ser. 43, 1660200 (2016). OPAL Collaboration (N Fischer et al.), “Measurement of parton shower observables with OPAL”, EPJ Web Conf. 120, 05001 (2016). AW Thomas, “QCD and a new paradigm for nuclear structure”, EPJ Web Conf. 123, 01003, arXiv 1606.05956 [nucl-th] (2016). H Wang, L Gong, C Li, S Li, H Qu, Z Wang and L Wu, “Overall design of magnet girder system for Heps-Tf”, WEPMR047 Proceedings (2016). G Valencia, “Colour octet extension of 2HDM”, Int. J. Mod. Phys. A 31, 1630033 (2016). P Urquijo, “Searching for dark matter at the Stawell Underground Physics Laboratory”, EPJ Web Conf. 123, 04002, arXiv 1605.03299 [physics.ins-det] (2016). C Balázs, P Athron, B Farmer and D Kim, “Naturalness, supersymmetry and dark matter”, PoS DSU2015 028 (2016).
SD Rindani, P Sharma and A Shivaji, “Unravelling the non-standard top and Higgs couplings in associated top-Higgs production at the high-luminosity LHC”, PoS TOP2015 033, arXiv 1512.07408 [hep-ph] (2016). J-J Wu, T-S Harry Lee, DB Leinweber, AW Thomas and RD Young, “Finite-volume Hamiltonian method for ππ scattering in lattice QCD”, JPS Conf. Proc. 10, 062002 (2016). D Leinweber, W Kamleh, A Kiratidis, Z-W Liu, S Mahbub, D Roberts, F Stokes, AW Thomas and J Wu, “N* spectroscopy from lattice QCD: the roper explained”, JPS Conf. Proc. 10, 010011 (2016). AJ Chambers, R Horsley, Y Nakamura, H Perlt, D Pleiter, PEL Rakow, G Schierholz, A Schiller, H Stüben, RD Young and JM Zanotti, “Applications of the Feynman-Hellmann theorem in hadron structure”, PoS LATTICE2015 125 (2016). J Dragos, R Horsley, W Kamleh, DB Leinweber, Y Nakamura, PEL Rakow, G Schierholz, RD Young and JM Zanotti, “Improved determination of hadron matrix elements using the variational method”, PoS LATTICE2015 328 (2016). SD Rindani, P Sharma and AW Thomas, “Polarization of the top quark as a probe of its chromomagnetic and chromoelectric couplings in single-top production at the Large Hadron Collider”, PoS TOP2015 063 (2016).
57 PUBLICATIONS
ARC CENTRE OF EXCELLENCE FOR PARTICLE PHYSICS AT THE TERASCALE
Conference presentations Sujeet Akula “Efficient perturbative determination of bubble wall profiles”, presenter, CosPA 2016: 13th International Symposium on Cosmology and Particle Astrophysics, December 2016.
Josh Charvetto “Vacuum correlation between the electromagnetic and strong forces”, invited talk, INPC 2016, September 2016.
Peter Athron
Sean Crosby
“Precision Higgs mass predictions in minimal and non-minimal SUSY models”, presenter.
“Renewal of Puppet for Australia-ATLAS”, invited talk, 25th Open Meeting of the Belle II Collaboration, October 2016.
Scientific/Organising Committee, SUSY 2016, July 2016.
Csaba Balázs “GAMBIT: the Global and Modular BSM Inference Tool”, presenter, DSU 2016 – 12th International Workshop on Dark Side of the Universe, July 2016. “Naturalness and supersymmetry”, invited talk, KITPC Workshop: New Physics at the LHC Run 2, July 2016. “GAMBIT”, invited talk, MC4BSM: 10th International Workshop Monte Carlo Tools for Physics Beyond the Standard Model, July 2016. “Dark matter properties implied by Fermi-LAT gamma ray residuals”, presenter, CosPA 2016: 13th International Symposium on Cosmology and Particle Astrophysics, November 2016. “A brief review of baryogenesis”, plenary, 4th International Workshop on Dark Matter, Dark Energy and Matter-Antimatter Asymmetry, December 2016.
Tommaso Baroncelli “L3 cooling taskforce report”, report talk, 26th B2GM, October 2016.
Ankit Beniwal “Combined analysis of effective Higgs portal dark matter models”, presenter, SUSY 2016, July 2016.
Lucien Boland “Australia-ATLAS tier 2 site update”, HEBiX, Fall 2016, San Fransisco, October 2016.
Goncalo Borges “CEPHFS: a new generation storage platform for Australian high energy physics”, presenter, 22nd International Conference on Computing on High Energy and Nuclear Physics (CHEP 2016), October 2016.
Alexander Chambers “Hadron structure from the Feynman-Hellmann Theorem”, presenter, INPC 2016, September 2016.
58 PUBLICATIONS
Nadine Fischer “Vincia for hadron colliders”, presenter, QCD@LHC 2016, August 2016.
Andrew Fowlie “Naturalness of the relaxion mechanism: Bayesian naturalness of next-to-minimal and minimal Supersymmetric Models", presenter, SUSY 2016, July 2016. “Naturalness of the relaxion mechanism”, presenter, CosPA 2016: 13th International Symposium on Cosmology and Particle Astrophysics, December 2016. “Bayesian approach to naturalness”, presenter, Fine-Tuning, the Multiverse and Life, November 2016.
Bahman Ghadirian “Radiative neutrino mass generation for a dimension-7 operator and its implication for charge lepton flavor violation”, presenter, CosPA 2016: 13th International Symposium on Cosmology and Particle Astrophysics, November 2016.
Dylan Harries “Mass spectrum and dark matter in the CSE6SSM”, presenter, SUSY 2016, July 2016. “The 750 GeV diphoton excess: models and precision tools”, presenter, SUSY 2016, July 2016.
Sophie Hollitt “Decay constants and SU (3) symmetry breaking in B-mesons with quenched relativistic”, invited talk, INPC 2016, September 2016.
Paul Jackson “Recent results from LHC”, invited talk, Symposium 2016 – Interplay between LHC and Flavor Physics, March 2016. “The recursive jigsaw reconstruction technique”, poster, ICHEP 2016, 38th International Conference on High Energy Physics, August 2016. “Recent ATLAS results on composite dynamics and dark matter”, invited talk, LIO 2016, September 2016.
ANNUAL REPORT
Archil Kobakhidze “Heavy axion solution of the strong CP problem”, presenter, PASCOS 2016, July 2016.
Cyril Lagger
“Welcome on behalf of IUPAP”, presenter, INPC 2016, September 2016.
Marco Milesi
“Constraining noncommutative space-time from GW150914”, presenter, CosPA 2016: 13th International Symposium on Cosmology and Particle Astrophysics, December 2016.
“Search for the associated production of a Higgs boson with a top quark pair in multilepton final states with the ATLAS detector”, presenter, APPC-AIC: Joint 13th Asia Pacific Physics Conference and 22nd Australian Institute of Physics Congress Incorporating the Australian Optical Society Conference, December 2016.
Lawrence Lee
Roman Nevzorov
“The recursive jigsaw reconstruction technique”, presenter, SUSY 2016, July 2016.
“On the smallness of the dark energy density in SUGRA models with Planck scale SUSY breaking and degenerate vacua”, presenter, SUSY 2016, July 2016.
Haitao Li “TMD Resummation for top quark pair production using SCET”, presenter, Effective Field Theories as Discovery Tools, September 2016.
“E6 inspired composite Higgs model and 750 GeV diphoton excess”, presenter, SUSY 2016, July 2016. “The 750 GeV diphoton LHC excesses from singlets in Exceptional Supersymmetric Standard Model”, presenter, SUSY 2016, July 2016.
Jinmian Li
Robert Perry
“Investigating light NMSSM pseudoscalar states with boosted ditau tagging”, presenter, SUSY 2016, July 2016.
“Chiral corrections to electromagnetic form factors in the NJL model”, invited talk, INPC 2016, September 2016.
Adrian Manning
Andreas Petridis
“Gravitational waves from low temperature phase transitions”, presenter, CosPA 2016: 13th International Symposium on Cosmology and Particle Astrophysics, November 2016.
“Low transverse momentum electrons, presenter, ATLAS Egamma Workshop”, November 2016.
Hrayr Matevosyan “Polarized quark hadronization”, invited talk, International Workshop on J-PARC Hadron Physics in 2016, March 2016. “The role of spin in quark hadronization”, invited talk, INPC 2016, September 2016.
Zachary Matthews “Leptonic CP violation and mass hierarchy in the presence of sterile neutrino”, presenter, SUSY 2016, July 2016. “Leptonic CP violation and mass hierarchy in the presence of sterile neutrino”, invited talk, INPC 2016, September 2016.
Bruce McKellar “I — What the International Union of Pure and Applied Physics does for physics and physicists" "II — Electric and magnetic dipole moments, topological phases and Bose-Einstein condensates”, plenary, Siam Physics Congress 2016, June 2016. “Basic research, open innovation and collaborative economy”, presenter, Fundamental Science and Society, July 2016. “The IUPAP-IUPAC JWG on new elements”, presenter, Annual meeting of IUPAP Commission C-12 on Nuclear Physics, September 2016. “The IUPAP-IUPAC JWG on new elements”, presenter, annual meeting of IUPAP Working Group 9, September 2016.
Marco Santoni “Applications of the recursive jigsaw to searches for SUSY”, presenter, SUSY 2016, July 2016.
Michael Schmidt “Sterile neutrino dark matter production from scalar decay”, presenter, Dark Side of the Universe DSU Workshop, July 2016. “Unitarisation of EFT amplitudes for dark matter searches at the LHC”, presenter, Identification of Dark Matter 2016, July 2016. “LHC vs precision experiments – a comparison of the sensitivity to LFV D6 operators QQLL”, presenter, SUSY 2016, July 2016. “Sterile neutrino dark matter – production from scalar decay”, invited talk, NuFact 2016, August 2016.
Abhishek Sharma “Unravelling the CP phase of top-Higgs coupling in associated production at the LHC”, presenter, SUSY 2016, July 2016.
Pankaj Sharma “Probing R-parity violation in neutrino-nucleus interactions”, presenter, DAE Symposium, December 2016. “Di-Higgs signatures from R-parity violating supersymmetry as the origin of neutrino mass”, presenter, SUSY 2016, July 2016. “Charged Higgs search in bosonic-decays using jet substructure at the LHC”, presenter, DAE Symposium, December 2016.
59 PUBLICATIONS
ARC CENTRE OF EXCELLENCE FOR PARTICLE PHYSICS AT THE TERASCALE
Peter Skands
Anthony Williams
“VINCIA for hadron colliders”, presenter, ICHEP 2016 38th International Conference on High Energy Physics, August 2016.
“Combined analysis of effective Higgs portal dark matter model”, plenary, Mass 2016 Conference at CP3-Origins, May 2016.
Anthony Thomas
“Stawell Underground Physics Laboratory (SUPL)”, invited talk, AIP Congress 2016, December 2016.
“QCD, atomic nuclei and neutron stars, plenary”, Humboldt Kolleg on Particle Physics, June 2016.
“Combined analysis of effective Higgs portal dark matter model”, presenter, ICHEP 2016 38th International Conference on High Energy Physics, August 2016.
“QCD nuclear physics”, plenary, 71st Fujihara seminar, July 2016. “Progress in understanding the nucleon sea”, plenary, International Workshop on Nonperturbaive Phenomena in Hadron and Particle Physics, May 2016. “Baryon-baryon interactions at high density”, plenary, International Symposium on Neutron Star Matter, November 2016. “Structure of finite nuclei starting at the quark level”, invited talk, INPC 2016, September 2016.
Raymond Volkas “What I think about when I think about dark matter”, invited talk, Beyond the Standard Model in Okinawa 2016, March 2016. “Radiative neutrino mass generation: models, flavour & the LHC”, invited talk, PACIFIC Conference 2016, September 2016. “Outlook for the discovery of new physics”, invited talk, CosPA 2016: 13th International Symposium on Cosmology and Particle Astrophysics, December 2016. “Radiative neutrino mass generation: models, flavour & the LHC”, invited talk, NCTS Annual Theory Meeting, December 2016.
Graham White “Colour breaking baryogenesis – semi-analytical approaches in particle cosmology”, presenter, SUSY 2016, July 2016. “Color breaking baryogenesis”, invited talk, East China Particle Physics Meeting, September 2016. “Electroweak baryogenesis in the Z3-invariant NMSSM”, presenter, CosPA 2016: 13th International Symposium on Cosmology and Particle Astrophysics, December 2016.
Martin White “The particle physics of dark matter”, invited talk, Diving into the Dark, July 2016. “The Global and Modular BSM Inference Tool (GAMBIT)”, presenter, SUSY 2016, July 2016.
60 PUBLICATIONS
Lei Wu “Monotop/monob signature in Natural SUSY”, presenter, CosPA 2016: 13th International Symposium on Cosmology and Particle Astrophysics, November 2016.
Ross Young “Towards high momentum transfer in lattice QCD”, invited talk, Probing Transverse Nucleon Structure at High Momentum Transfer, April 2016. “Infrared features of dynamical QED+QCD simulations”, presenter, Lattice 2016: 34th International Symposium on Lattice Field Theory, July 2016. “Q-weak and searches of new physics in parity-violating e-p scattering”, invited talk, Hadronic Contributions to New Physics Searches (HC2NP), September 2016. “Partonic charge symmetry violation in the nucleon”, presenter, INPC 2016, September 2016.
Zhao-Huan Yu “Triplet-quadruplet fermionic dark matter”, invited talk, East China Particle Physics Meeting, September 2016.
Jason Yue “Gravitational waves from the phase transition of a nonlinearly realised electroweak symmetry”, presenter, Strong and Electroweak Matter 2016, July 2016.
Daniele Zanzi “ATLAS trigger performance (Jets, taus and Etmiss)”, plenary talk, Atlas Overview Week, June 2016.
ANNUAL REPORT
CoEPP annual workshop Presentations S Akula, “SUGRA GUTS”. P Athron, “Exploring new physics with flexible tools”. C Balázs, “GAMBIT” (the Global and Modular BSM Inference Tool). E Barberio, “SABRE dark matter search and the SUPL underground facility”. N Bell, “Particle–antiparticle asymmetries”. G Busoni, “Dark matter”. Y Cai, “Semi-annihilating dark matter”. A Clark (University of Geneva), “Comments on ATLAS Run 2” (2015–17). J Clarke, “Self-interacting dark matter direct detection (and implications for Stawell)”. HV Cliff (University of Cambridge), “Cambridge, CoEPP and the LHC”. T Corbett (Stony Brook), “Effective field theory”. N Dawe, “Deep learning jet images”. M Dolan (SLAC National Accelerator Laboratory), “Higgs physics”. D Dossett, “Calibration and alignment at the Belle II experiment”. K Finelli, “ATLAS top quark physics in Run 2”. R Foot, “Dark matter”. A Fowlie, “Fine tuning relaxion models”. PD Jackson, “Experimental anomalies”. A Kobakhidze, “New solution to the strong CP problem with exotic quarks”. M Kruse (Duke University), “Duke and CoEPP: studies of multilepton final states”.
VAM Radescu (Ruprecht-Karls-Universitaet Heidelberg), “QCD and parton distribution functions” and “Precision of proton structure for discoveries at LHC”. M Schmidt, Neutrino Physics, “Origin of neutrino mass and its experimental test”. F Scutti, “Inclusive search for same-sign di-lepton signatures at the ATLAS experiment”. P Sharma, “Optimising the charged Higgs searches at the LHC in 2HDM”. GN Taylor, “Collider detector design” and “Interaction of particles with matter summary of CoEPP and activities”. F Tenchini, “Belle 2 PID performance and vertexing”. M Trodden (University of Pennsylvania), “Theoretical aspects of cosmic acceleration”. F Ungaro, “Search for third generation squarks with ATLAS Run-II data”. P Urquijo, “Belle II physics”. J Wang, “Measurement of the Wt production cross-section at –
√s = 13 TeV”.
L Wu, “Possible phenomenological explanations of 750 GeV resonance”. Z Yu (University of Melbourne), “The 750 GeV diphoton excess and its possible connection to dark matter”.
Posters N Barrie, “Gravitational wave instabilities in the cosmic neutrino background”. A Beniwal, “Combined analysis of effective Higgs portal dark matter models”. I Bigaran, “Testing simplified dark matter models at the LHC”.
L Lee Jr, “Searches for strongly produced supersymmetry in ATLAS Run II”.
T Bloomfield, “Measurement of direct CP violation and branching ratio in B0 → D0 π0 Using Belle Detector”.
H Li, “Resummation effects on top quark pair production”.
A Brennan, “Simplified models of dark matter at ATLAS”.
J Li, “Search for light NMSSM pseudoscalar in neutralino decays with di-tau tagging”.
G Caria, “Software improvements for the Belle II SVD”.
K Mcdonald, “Three-loop models of neutrino mass measure the age of the Universe to 1%”. A Morley, “Tracking and minimum-bias analysis in ATLAS Run 2”. J Mould (Swinburne University), “Taipan, an AAO/ARC project”. R Nevzorov, “LHC signatures and cosmological implications of the E6 inspired SUSY models”. U Parzefall (University of Freiburg), “The ATLAS strip tracker upgrade”. AG Petridis, “Summary of the supersymmetric electroweak searches in Run I and prospects for Run II”.
J Clarke, “Self-interacting dark matter direct detection (and implications for Stawell)”. P Cox, “Unnatural Composite Higgs at the LHC”. R Coy, “Freeze-in of light dark matter”. T Dutka, “Neutral naturalness and leptogenesis”. D Duvnjak, “Remote installation of the SctRodDaq Software”. J Ellis, “TiKZ-Feynman: a new program for drawing Feynman diagrams in LaTeX”. N Fischer, “Matrix-element corrections in Vincia”. J Gargalionis, “Radiative neutrino mass models at the LHC”.
61 PUBLICATIONS
ARC CENTRE OF EXCELLENCE FOR PARTICLE PHYSICS AT THE TERASCALE
B Ghadirian, “Radiative neutrino mass generation”. D Harries, “Sparticle spectrum and dark matter observables in an E6 inspired SUSY model with a 125 GeV Higgs”. A Hawthorne, “Direct CP violation in B →Ksπ at Belle”. 0
0
S Hollitt, “B-physics in lattice QCD and at Belle II”. C Hsu, “Belle”. A Huitfeldt, “Development of a method to share SCT clusters in the ATLAS detector track reconstruction”. N Ivancevic, “Towards a regularization that respects spacetime structure”. J Koo, “Cosmic ray telescope for muon flux measurements at SUPL”. C Lagger, “Backreaction of particle production on false vacuum decay”. B Le, "Measuring Higgs properties with H →ττ decays at – √s = 13 TeV with ATLAS". R Leane, “Indirect detection of a complete dark sector”. A Lifson, “Maximally helicity violating amplitudes”. S Lonsdale, “Origin of matter and dark matter from a broken mirror symmetry”.
M Milesi, “Non prompt lepton background estimation for the ttH → ℓℓ + jets analysis in the ATLAS experiment @LHC”. F Nuti, “Search for anomalous production of prompt same-sign lepton pairs and doubly charged Higgs with 8 TeV data”. D Peukert, “Studying the use of recursive jigsaw variables in the ATLAS Z+Met search for supersymmetry”. C Pyke, “Experiment at SUPL”. P Rados, “Search for the VH production of the Higgs boson using H → WW* decays with the ATLAS detector”. N Rajcic, “Tagging jets and neural nets”. T Ruggeri, “Background simulations at SUPL”. M Santoni, “Studies of multi b-jets final states using the recursive jigsaw reconstruction technique”. A Scaffidi, “Implementation of radiative muon decays for dark matter analyses”. M Schroor, “Dark QCD”. C Suster, “Beam spot studies in ATLAS Run 2”. M Talia, “The effective MSSM”. T Taylor, “Same-sign WW scattering analysis”.
C MacQueen, “Shedding light on dark matter: the search for a dark photon in radiative processes at Belle”.
E Waheed, “Right handed currents and other new physics in semileptonic B decays”.
I Mahmood, “Experiment at SUPL”.
D Wakeham, “Higgs inflation”.
A Manning, “Fermions in non-inertial frames”.
J Webb, “Belle II SVD measurements”.
M McDonald, “Determination of the tau energy scale uncertainty using single particle response measurements for Run II”.
G White, “Colour breaking baryogenesis”.
P McNamara, “The ATLAS tau FTK trigger”.
62 PUBLICATIONS
S Williams, “Belle II SVD construction”. J Yue, “Baryogenesis with electroweak symmetry realised non-linearly”.
ANNUAL REPORT
63 PUBLICATIONS
PERFORMANCE
ANNUAL REPORT
Prizes and awards Wessam Badr
Daniel Murnane
ND Goldsworthy Scholarship for Physics (MSc and PhD) Award, University of Melbourne
“3 Minutes Thesis” Award, Faculty of Science, University of Adelaide
Nicole Bell
Joni Pham
Fellow of the American Physical Society
The Klein Prize in Experimental Physics Award, University of Melbourne
Joshua Ellis
Harry Poulter
ND Goldsworthy Scholarship for Physics (MSc and PhD) Award, University of Melbourne
CoEPP Scholarship
John Gargalionis The Professor Kernot Research Scholarship in Physics Award, University of Melbourne
Paul Jackson Distinguished Award for Sustained Research, University of Adelaide
Stephen Keyte
Shi Qiu CoEPP Scholarship
Isaac Sanderson ND Goldsworthy Scholarship for Physics (MSc and PhD) Award, University of Melbourne
Marco Santoni Runner-up: CoEPP Workshop Poster Competition
ND Goldsworthy Scholarship for Physics (MSc and PhD) Award, University of Melbourne
Brian Le Winner: CoEPP Workshop Poster Competition
Rebecca Leane The Betty Laby ECR Travel Bursary Award, University of Melbourne Young Scientist Research Prize, Royal Society of Victoria
Ruihao Li CoEPP Scholarship
Shelley Liang Runner-up: CoEPP Workshop Poster Competition
Millie McDonald John Tyndall Scholarship, University of Melbourne
Bruce McKellar T.D. Lee Prize of “The Universe”: The 1993 discovery of the HeMcKellar-Wilkens (HMW) Phase, “The Universe” ACosPA Org
Associate Professor Nicole Bell was named a Fellow of the American Physical Society (APS) “For fundamental contributions regarding the interface of astrophysics and particle physics, particularly in neutrino astrophysics and cosmology, and dark matter phenomenology.”
65 PERFORMANCE
ARC CENTRE OF EXCELLENCE FOR PARTICLE PHYSICS AT THE TERASCALE
Phiala Shanahan
Geoffrey Taylor
Winner 2016 Bragg Gold Medal, Australian Institute of Physics
Redmond Barry Distinguished Professor, University of Melbourne
Science Excellence Awards in South Australia – PhD Research Excellence, South Australia Department of State Development 2016 Postgraduate Alumni University Medalist, University of Adelaide 2017 Dissertation Award of the Topical Group on Hadron Physics, American Physical Society
Justin Tan The Jean E Laby Bursary Award, University of Melbourne
Ray Volkas 2016 Harrie Massey Medal and Prize, Institute of Physics/Australian Institute of Physics
David Wakeham ND Goldsworthy Scholarship for Physics (MSc and PhD) Award, University of Melbourne
CoEPP Scholarship
Media report In 2016, CoEPP received a total of 298 media “hits” (print and online) with a potential viewership of 28,073,741 (data sourced through Meltwater). Stories appeared in national and international outlets, and via syndicated press. Coverage included stories about SUPL, Photowalk exhibition, CoEPP involvement in the Collider exhibition at the Powerhouse Museum, and new partnerships forged with Fermilab in the United States and IHEP in China. CoEPP worked closely with journalists on a number of feature articles, including “Digging for
PhD student Rebecca Leane was awarded the Royal Society of Victoria Young Scientist Research Prize for the Physical Sciences.
66 PERFORMANCE
dark matter” (Lisa Clausen, SBS online), and “Hunt for dark matter sends scientists underground in a Victorian goldmine” (Bridie Smith, The Age). CoEPP generated a total of 11 media releases/news items over the year.
ANNUAL REPORT
Centre-recognised leadership Boards and official roles Csaba Balázs International Advisory Board member, Dark Side of the Universe International Workshop series Editorial Board member, Scientific Reports (Nature Publishing) Particle Phenomenology Group Leader, Monash University Convener of Core Development, GAMBIT collaboration
Archil Kobakhidze Co-chair, CosPA 2016
Bruce McKellar AC President, International Union of Pure and Applied Physics
Martin Sevior Belle and Belle II Executive Board member
Co-chair, SUSY 2016 Conference
Member, International Advisory Committee, Europe–Asia–Pacific Summer School
Dark Matter Working Group leader, Australian CTA contingent
Hadronic B-Decays group co-convener – Belle
Elisabetta Barberio
Peter Skands
University of Melbourne ATLAS Team Leader
International Advisory Board member, MPI@LHC workshop series
Member, Publication Committee of ATLAS
International Advisory Board member, CERN-Fermilab HadronCollider Physics Summer School
ATLAS Fast Track Trigger Institution Board member Spokesperson, SABRE South Institutional Board Chair, SABRE South
Nicole Bell Editorial Board member, Scientific Reports (Nature Publishing)
International Advisory Board member, Monte Carlo Tools for Beyond the Standard Model Physics (MC4BSM) workshop series Member, conference committee, Workshop on High-Precision Alpha S measurements: from LHC to FCC-ee Leader, VINCIA collaboration
Co-chair, pre-SUSY summer school 2016
Geoffrey Taylor
International Advisory Committee, CosPA 2016 conference
ATLAS National Contact Physicist (Australia)
International Advisory Committee, International Neutrino Summer School 2016
Vice-Chair and Chair-designate, Asian Committee for Future Accelerators
General Assembly member, Asia–Pacific Organization for Cosmology and Particle Astrophysics
Member, AsiaHEP Asia–Pacific High Energy Physics Panel
Caroline Hamilton Digital Governance Committee member, Interactions Collaboration Board member, Interactions Collaboration
Paul Jackson
Member, International Advisory Committee CEPC (China) Australian Representative, ATLAS and WLCG Resource Review boards Member, Melbourne Grammar School Council Member, Melbourne Grammar School Foundation Board Member, International Advisory Committee, LCWS2016
University of Adelaide ATLAS Team Leader
Member, International Advisory Committee, Lepton Photon 2017
ATLAS Collaboration Board member
Member, International Advisory Committee, International Conference on High Energy Physics
Chair, Advisory Board, ATLAS Collaboration Board ATLAS ITK Institute Board member ATLAS SCT Institute Board member International Particle Physics Outreach Group National Contact Physicist
Member, International Advisory Committee, Rencontres de Vietnam 2016 Chair, (NSS) IEEE NSS-MIC, Sydney 2018 Invited Australian member, Funding Agencies for Large Colliders
Belle II Institute Board member Member, International Advisory Committee, International Conference on High Energy Physics Theory to Experiment
67 PERFORMANCE
ARC CENTRE OF EXCELLENCE FOR PARTICLE PHYSICS AT THE TERASCALE
Anthony Thomas
Martin White
Past-Chair, International Union of Pure and Applied Physics Working Group on International Cooperation in Nuclear Physics
Co-leader of GAMBIT collaboration
Vice-Chair, Asian Nuclear Physics Association Editorial Board member, Journal of Physics G Editorial Board member, Progress in Particle and Nuclear Physics Chair, International Conference on Nuclear Physics 2016 Chair, Program Committee, International Conference on Nuclear Physics 2016 Member, local organising committee, International Conference on Nuclear Physics 2016 Member, International Advisory Committee, 9th Workshop on Hadron Physics in China and Opportunities Worldwide Member, International Advisory Committee, Asia Pacific Few Body Conference 2017 Member, International Advisory Committee, Baryons 2016
Member, local organising committee, SUSY 2016 Session chair at “(Re) interpreting the results of new physics searches at the LHC” (CERN, Geneva) Co-organiser of international workshop on statistical inference for particle astrophysics (Oban, Scotland)
Anthony Williams SABRE Institutional Board Representative Member, SUPL Project Steering Committee Member, International Organising Committee, IHEP-T2E 2017, Malaysia Member, local organising committee, International Conference on Nuclear Physics 2016
Bruce Yabsley
Member, International Advisory Committee, Hadron 2017
Member, International Advisory Committee, International Workshop on Charm Physics
Member, International Advisory Committee, NSTAR 2017
Member, ATLAS Speakers Committee
Phillip Urquijo
ATLAS and LHC working groups, Higgs analysis groups
Physics Coordinator, Belle II Belle and Belle II Executive Board member Belle II Institution Board member
Elisabetta Barberio
CKM convener, Belle
Institute Board representative, FTK
Kevin Varvell
Subconvenor, Higgs to tau tau
University of Sydney ATLAS Team Leader
Amelia Brennan
Belle and Belle II Institute Board member
LHC Dark Matter Forum
Member, local organising committee, SUSY 2016
Kevin Finelli
Member, local Organising committee, CosPA 2016
Raymond Volkas Vice-President, Asia–Pacific Organization for Cosmology and Particle Astrophysics
Top working group, single-top quark subgroup convener t W analysis contact ATLAS contact for common fiducial acceptance on LHCTOPWG ATLAS Top cross-section subgroup convenor
Member, Executive Committee, Division of Astrophysics, Cosmology and Gravitation, Association of Asia–Pacific Physical Societies
Paul Jackson
Member, International Advisory Committee for the International Conference on Neutrino Physics and Astrophysics
Supersymmetry squark/gluino search leader
Commission 11 (C-11) member, International Union of Pure and Applied Physics
Convenor, ATLAS supersymmetry recursive jigsaw analysis
Takashi Kubota
Divisional Associate Editor (Particles and Fields), Physical Review Letters
Subconvenor and editor, VH, H → WW
Co-chair, SUSY 2016
Lawrence Lee ATLAS Supersymmetry 0-lepton search analysis contact
68 PERFORMANCE
ANNUAL REPORT
Antonio Limosani
Abhishek Sharma
Editor and coordinator, AIDA
ATLAS low pT e/gamma tag and probe
Chair, ATLAS Software Performance Management Board
Phillip Urquijo
Responsible for external packages in the ATLAS Software Infrastructure team
Anthony Morley Convenor, ATLAS Beamspot Group Convener and editor, ATLAS minimum bias 13 TeV Editorial Board Chair, reconstruction of hadronic decay products of tau leptons with the ATLAS experiment
Brian Petersen
Editor, New Phenomena Producing Trilepton Resonances FTK working group member Tau trigger working group member
Jin Wang HGam PMG contact
Martin White Chair, editorial board for ATLAS paper on general gauge mediation
Supersymmetric partners to quarks and gluons
Editorial board member, ATLAS dilepton stop searches
Andreas Petridis
Bruce Yabsley
Working group convenor, ATLAS Supersymmetry EWK
ππΥ analysis contact
ATLAS 2/3 lepton supersymmetry search analysis contact ATLAS low pT e/gamma tag and probe
ATLAS Subgroup convenor, onia production and b cross-section measurements
Federico Scutti
Daniele Zanzi
Contact and editor, same-sign di-lepton analysis within the ATLAS EXOTICS working group
Sub-convenor, CP for Higgs to tautau
Editor and analyser, tau trigger efficiency measurement notes
Member, Higgs working group coordination
Convener, tau trigger slice
69 PERFORMANCE
ARC CENTRE OF EXCELLENCE FOR PARTICLE PHYSICS AT THE TERASCALE
Key performance indicators KPI
Target 2016
Actual 2016
Number of research outputs – journal publications
80
219a
Number of research outputs – refereed conference proceedings
35
23
Quality of research outputs
50%
96%
1,000
5,991
Number of invited talks/papers/keynote lectures at major international meetings
40
23
Number and nature of commentaries about the Centre’s achievements – media releases
6
11
Number and nature of commentaries about the Centre’s achievements – articles (including television and radio)
4
298
Number of attended professional training courses for staff and postgraduate students
15
21
Number of Centre attendees at all professional training courses
20
33
Number of new postgraduate students working on core Centre research and supervised by Centre staff – PhD
12
12
Number of new postgraduate students working on core Centre research and supervised by Centre staff – Masters by Research and Masters by Coursework
8
11
New postdoctoral researchers working on core Centre research
2
0
New Honours students working on core Centre research and supervised by Centre staff
12
5
Number of postgraduate completions and completion times by students working on core Centre research and supervised by Centre staff
14
16
Number early career researchers (within 5 years of completing PhD) working on core Centre research
16
25
Number of students mentored
60
97
Number of mentoring programs
7
7
Number international visitors and visiting Fellows
15
42
Number of national/international workshops held/organised by the Centre
3
4b
Number of visits to overseas laboratories and facilities
35
81
Number of government/industry and business community briefings
5
6
Citation data for publications
a 125 ATLAS, 24 Belle II, 10 CDF, 94 theory and other. Activities with Belle and CDF are listed in the annual report but are not included in
KPI reporting. b Includes SUSY 2016, INPC, CosPA. CoEPP centre workshop.
70 PERFORMANCE
ANNUAL REPORT
Number and nature of public awareness programs KPI
Target 2016
Actual 2016
School visits
20
13
National Science Week event participation
5
3
Other public activities
6
4
Target 2016
Actual 2016
20,000
43,429
Public talks given by Centre staff
20
12
Prizes and awards
16
29
Number of new organisations collaborating with or involved in the Centre
2
2
Currency of information on the Centre’s website KPI Number of website hits
Examples of relevant interdisciplinary research supported by the Centre KPI FCC research studya
Target 2016
Actual 2016
1
1
a CoEPP is participating with CERN and the Australian Synchroton through a formal Memorandum of Understanding in accelerator science on a study of some specific aspects of a Future Circular Collider (FCC). This study will investigate aspects on the long term goal of a hadron collider with a centre-of-mass energy of the order of 100TeV in a new tunnel of 80–100 km circumference. The study also includes a lepton collider and its detectors as a potential intermediate step.
71 PERFORMANCE
ARC CENTRE OF EXCELLENCE FOR PARTICLE PHYSICS AT THE TERASCALE
Financial statements Statement of income and expenditure for the year ended 31 December 2016
2011 reporting period
Carry forward Income
ARC indexed income Node contribution
2012 reporting period
2013 reporting period
2014 reporting period
$0
$3,738,983
$3,940,654a
$4,403,387b
$3,656,701
$3,797,390
$3,943,493
$4,062,667
$1,632,000
c
$1,238,678c
$752,000
$1,151,785
$484,785
$161,595
$64,638
$1,055
$17,333
$201,904d
$1,880
Total income
$5,289,756
$5,051,508
$5,458,777
$5,367,863
Balance
$5,289,756
$8,790,491
$9,399,431
$9,771,250
$1,132,439
$2,989,585
$3,951,676
$3,468,297
$28,365
$186,544
$61,687
$161,739
$265,379
$80,923
$582,041e
$559,307
$610,838
$666,854
$57,370
$35,482
$49,309
$497,999
$155,907
$99,555
$49,886
$60,774
$428,462
$153,522
NeCTAR Other
Expenditure
Salaries Equipment Maintenance Travel, accomodation and conferences
$260,725
Scholarships Services and general Outreach and media
$129,244
h
NeCTAR
$293,622
New initiatives
Total expenditure
$1,550,773
$4,849,806
$5,374,861
$5,242,091
Balance
$3,738,983
$3,940,685
$4,024,570
$4,529,160
Table continues on opposite page
72 PERFORMANCE
ANNUAL REPORT
2015 reporting 2016 reporting period period Carry forward
2017 reporting period (estimated)
2018 to end of centre (estimated)
$4,529,160
$4,412,131
$3,310,641
$2,634,073
ARC indexed income
$4,135,430
$4,205,732
$4,268,819
$0
Node contribution
$1,195,368
$1,195,640
$1,192,000
$0
$0
$0
$0
$0
$18,182
$2,500
$5,000
$2,500
Total income
$5,348,980
$5,403,872
$5,465,819
$2,500
Balance
$9,878,140
$9,816,003
$8,776,460
$2,636,573
$4,118,841
$4,378,042
$4,037,179
$1,947,373
$40,999
$143,171
$261,912
$0
Maintenance
$225,788f
$755,335f
$426,095
$295,923
Travel, accomodation and conferences
$648,111
$886,871
$878,201
$348,278
Scholarships
$150,717g
$140,626g
$135,000
$45,000
Services and general
$186,010
$96,578
$148,000
$0
Outreach and mediah
$89,614
$56,643
$106,000
$0
$5,929
$32
$0
$0
$48,063
$150,000
$0
Income
NeCTAR Other
Expenditure
Salaries Equipment
NeCTAR New initiatives
Total expenditure
$5,466,009
$6,505,362
$6,142,387
$2,636,573i
Balance
$4,412,131
$3,310,641
$2,634,073
$0
73 PERFORMANCE
ARC CENTRE OF EXCELLENCE FOR PARTICLE PHYSICS AT THE TERASCALE
Financial summary Notes to the statement of income and expenditure a Carry forward adjustments from 2012. b Adjustment to Adelaide opening balances, due to timing differences in income transfer between University of Melbourne and University of Adelaide and carry forward adjustments to Melbourne and Sydney. c Monash School of Physics Contribution for 2013 was paid in Q1 2014 and is reported in 2014 Annual Report.
ARC funding The Centre for Excellence for Particle Physics at the Terascale is funded by the Australian Government through the Australian Research Council. The funding for the Centre is for seven years with an annual base contribution to the Centre of $3,600,000. Additional amounts each year for indexation increase this funding. In 2016 the Centre received $4,205,732 of indexed ARC funds. This was distributed to the four nodes of the Centre according to the Centre’s inter-institutional agreement and was used to fund operational expenses.
d “Other” comprises adjustments relating to prior year income adjustments, corrections to NeCTAR carry forward, and income timing differences.
Institutional funding
e Includes total expense for ATLAS M&O of $302,217, with $140,685 relating to 2013 expense.
Under the Centre’s funding agreement with the ARC the collaborating institutions are required to contribute the following annual amounts:
f
No payment made for ATLAS M&O in 2015. Additional payment made in 2016.
g Scholarship amount includes additional expense for student support and summer studentships. h Outreach and Media was included under Services and General in 2011 and 2012. i
Expenditure estimates have been allocated between salaries, scholarships, travel and maintenance as the Centre winds up operation.
The University of Melbourne
$660,000
The University of Sydney
$235,000
Monash University
$132,000
The University of Adelaide
$165,000
Payments for 2016 from the institution were: The University of Melbourne
$660,000
ARC contract
The University of Sydney
$235,000
The Centre for Excellence for Particle Physics at the Terascale commenced as a Centre of Excellence on 1 January 2011. Funding was approved for seven years ending in December 2017, with a review held in 2014. Additional funding and in-kind support from the four collaborating institutions and in-kind support from the seven partner institutions provide further funding and support for the Centre.
Monash University
$135,640
The University of Adelaide
$165,000
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Other $2,500
2016 income Total income $5,401,372
Node contribution $1,195,640
ARC indexed income $4,205,732
Services and general $96,578 Scholarships $140,626 Equipment $143,171 Maintenance $755,335
NeCTAR $32 New initiatives $48,063 Outreach and media $56,643
2016 expenditure Total expenditure $6,505,362
Travel, accomodation and conferences $886,871 Salaries $4,378,042
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In-kind contributions
Notes on in-kind contributions 2016 reporting period
Contributor University of Melbourne
$43,200
University of Adelaide
$601,960
University of Adelaide – Research Computing
$3,000
University of Sydney
$515,548
University of Sydney – Research Computing
$3,000
Monash University
$143,106
University of Pennsylvania
$11,227
Cambridge University
$11,227
L’Universite de Geneve
$11,227
Albert Ludwigs Universität Freiburg
$33,680
INFN Sezione di Milano
$22,454
Duke University
$11,227
University of Minnesota
$22,856
University of Melbourne shared General Purpose GPU
$19,000
University of Melbourne – Cloud computer
$361,788
Total
Total contribution $4,370,913
CERN provides considerable in-kind support to CoEPP’s research activities predominantly through access to the LHC.
$2,556,413
University of Melbourne – Research Computing
In-kind contributions
Decrease in Research Computing in-kind in 2016 due to change in costing model, without changes to service levels.
$4,370,913
Cloud computer
General purpose CPU
University of Melbourne Research computing
University of Adelaide University of Sydney Monash University International universities 0
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$1,000,000
$2,000,000
$3,000,000
ANNUAL REPORT
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ANNUAL REPORT
Activity plan Higgs program In 2017, CoEPP researchers will analyse the new data from Run 2 for important and challenging Higgs boson property measurements. Twice as much data is now available from the runs in 2016 than expected; this means that analysis studies can proceed deeper into the rarer decay channels. These include the observation of the H → đ?œ?đ?œ? decay, the measurement of the CP quantum number of the Higgs boson coupling to fermions, the search for the Higgs boson production in association with a pair of top quarks and the measurement of the VH (→WW) cross-section.
Higgs physics theory With new data at 13 TeV becoming available, CoEPP theorists will further explore properties of the 125 GeV Higgs boson and focus on data analysis within the effective field theory approach to the SM. Theorists will aim to pin down evidence for new physics in measurements of various couplings, such as Higgs–gauge boson coupling and Higgs–top quark coupling. New strategies for precision measurements of the Higgs couplings in current and future experiments will also be investigated. The new Higgs data will allow testing of various BSM scenarios, such as multi-Higgs models, supersymmetric theories and other theories. Model building will also be an active research area. CoEPP theorists will investigate cosmological implications of the Higgs boson. Research activities will include the electroweak phase transition and baryogenesis, and the Higgs vacuum stability. Further studies of theoretical ideas, such as SUSY, scale invariance and cosmological relaxation, motivated by the naturalness principle will also be a focus.
Neutrino mass CoEPP researchers will expand their study of neutrino mass models and mechanisms, with an emphasis on approaches that can be tested in experiments operating at both the energy and precision frontiers. New particles predicted in neutrino mass models, particularly radiative models, can give distinctive signatures at the LHC, and CoEPP members will continue their studies of promising variants of such frameworks. Precision tests of neutrino mass models will be explored, including lepton flavour violating processes, in addition to general studies of effective operators that can play a role in neutrino mass generation. These tests will provide further information about the underlying mechanism of neutrino mass, and in some cases allow general statements to be made about the viability of groups of models. CoEPP researchers will also study connections between the neutrino mass problem and other known shortcomings of the SM. This research will include an exploration of relationships between the origin of neutrino mass and the nature of dark matter – CoEPP scientists will expand previous ideas and take them in new directions. This research will extend the scope of experimental explorations of neutrino mass models, enlarging the spectrum of relevant experiments from the LHC and precision experiments to include dark matter searches (in particular, direct- and indirectdetection experiments).
The research program on the radiative generation of neutrino mass will continue to be pursued vigorously during 2017, involving researchers at all four nodes. Specific lines of investigation will include the study of the connections between radiative neutrino mass generation and some anomalies in flavour physics experiments that hint at the violation of lepton flavour universality (Melbourne and Monash). Exotic particles such as scalar leptoquarks are central to both topics, and thus suggest a possible connection. This work will benefit from Australian involvement in the Belle II experiment, which will take data from 2018 onwards and will help resolve these anomalies, possibly by confirming the existence of new physics. The use of effective operators that violate lepton number by two units has formed the basis of a significant fraction of the CoEPP research on neutrino mass generation. In 2017, this approach will be extended to operators that also contain standard model gauge fields, an area that has been neglected until now (Adelaide, Melbourne and Sydney). Finally, researchers at the Adelaide, Melbourne and Sydney nodes plan to collaborate on a major review article on radiative neutrino mass generation during 2017.
Precision tests Efforts to test the predictions of the Standard Model at the highest levels of precision will continue using ATLAS data collected in Run 2 of the LHC. CoEPP researchers have established leadership in the analysis of the top quark, soft QCD signatures, and electroweak physics in the ATLAS experiment, and will continue to develop new and innovative techniques to fully exploit Run 2 data within these areas. The analysis of final states with a single top quark in association with a W boson will be extended to test predictions of perturbative QCD in new ways. Additionally, an inclusive analysis to study signatures with a two-lepton final state will be developed, which combines the experience of researchers working on several types of SM measurements to create a unique analysis that is more inclusive than traditional cross-section measurements. Such studies provide another way to look for new physics beyond the SM by testing SM predictions at the most extreme limits available to experimentalists today. Full results from the Q-weak experiment at Jefferson Lab, Virginia (United States), will be reported in 2016. This is the first dedicated measurement to determine the electroweak charge of the proton, with a precision that can probe new physics in the multi-TeV range. The final results will be based on the full dataset, following the preliminary result published in 2013, which analysed just the first 4% of data taken.
Dark matter Dark matter research in 2017 will continue to concentrate on model building, phenomenology and collider detection. CoEPP theorists will develop Beyond the Standard Model theories that incorporate complete dark matter sectors. Theoretical work on the formulation and validity of dark matter effective field theories will also be performed. Experimental studies of LHC dark matter signals will continue, with key CoEPP participation in the ATLAS mono-X working groups. These experimental results will be used to constrain effective field theories and simplified models. Complementary constraints on dark matter
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models will also be formulated using indirect detection techniques. In particular, models that can account for the Galactic centre gamma ray excess via the annihilation of various dark matter particles will be examined. The GAMBIT collaboration will continue to perform statistical fits to collider and astrophysical dark matter information; code and results are planned for release within the year. During 2016, significant development has occurred for the design and construction of the Stawell Underground Physics Laboratory (SUPL) and the dark matter detector, which will be located in the laboratory (Sodium-iodide with Active Background REjection – SABRE). The laboratory and the experiment have been fully designed; during 2017, it is intended that the laboratory and fitout will be completed, to enable the SABRE experiment to be in place for 2018.
Supersymmetry Results will be published for the most exhaustive statistical inference of the plausibility, naturalness, and discovery prospects of the seven-parameter Minimal Supersymmetric Standard Model. A similar outcome for more constrained versions of the model is planned to follow. This work will be done by the GAMBIT Collaboration, which consists of 28 physicists from about 20 international institutes, including CoEPP members from Adelaide and Monash. In the context of the Next-to-Minimal Supersymmetric Standard Model, CoEPP researchers will publish their results demonstrating that plausibility of electroweak baryogenesis and thermal freeze out of dark matter can account for all the observed matter content of the universe. CoEPP theorists will scrutinise the exceptional supersymmetric Standard Model (E6SSM) further, with more detailed studies of Higgs physics, the implications of dark matter abundance measurements and new findings from direct-detection dark matter experiments. Diphoton signatures will be examined in this context because E6-inspired models are one of the leading possibilities to explain any potential diphoton excess. CoEPP experimental researchers have pioneered new techniques to perform searches for physics beyond the SM, involving the development of new kinematic variables for particles that decay semi-invisibly. An analysis in the flagship “jets plus missing energy” discovery channel is in the final stages of completion on the Run 2 ATLAS dataset, and will be updated with new data in 2016. This has expanded the discovery reach for supersymmetric squark and gluino production. Other analyses are targeting final states with two or more leptons, and various final states with combinations of leptons and b jets. Taken together, these analyses probe gluino and weak gaugino production, plus all three generations of squarks.
Exotic mesons Further progress in exotic meson studies at the LHC will depend on developing searches in new final states, many of them quite difficult to reconstruct. This work has already begun, using Run 1 data as a test bed. During 2017, the focus will shift to Run 2 data, where the higher collision energy provides opportunities through harder momentum spectra and larger rates, and further challenges through tighter trigger conditions for reconstructing exotic meson decays. This work complements preparations being carried out by CoEPP experimentalists for the future Belle II project.
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Research computing In 2017, the Research Computing team will continue to focus on providing excellence in resource reliability and availability. It is also expected that greater engagement with researchers will enhance the services the team provides and increase their effective use. Continued innovation is a must in the research computing field. As the world moves towards software-as-a-service computing models, and technology allows a paradigm shift towards infrastructure as code, the nature of system administration and provision of computing services will evolve tremendously. The Research Computing team will concertedly drive CoEPP’s computing services towards the emerging technologies and approaches that are delivering the disruptive power of new enterprises in the commercial sector. In addition to work within CoEPP, the Research Computing team will continue to provide support to the BORG project for the Astro group at the University of Melbourne. It will also provide Ceph Cluster expertise for the University Research Services Team.
Management and governance The IAC will continue its support of the Centre. At the meeting of the IAC in Chicago in August 2016, the committee noted that, although the Centre was unsuccessful in its bid for a new Centre, they continued to have confidence in the Centre’s ability to build on the strengths already in place and its capability to carry out the very significant plans clearly stated in the proposal.
Personnel Each year, CoEPP has steadily increased its intake of research higher-degree students. Increases across all nodes will be seen in 2017, particularly within the new research groups in Adelaide and Sydney (experimental and theory, respectively). This will bring new challenges in future years because Centre funding will cease from the current round in 2018. Nevertheless, the Centre is looking to the future. As a priority, all Centre researchers are seeking additional funding sources to continue, in part, some of the current Centre activities. Some of these funding options are student scholarships and travel funds through their respective universities, industry support, and potential government funding for activities. The Centre is grateful for ongoing institutional support, in various forms, from collaborating organisations.
Education and development Education and development activities will continue to feature strongly across CoEPP in 2017. The graduate summer school will be run for a fourth year and again held as the lead-in to the annual scientific workshop in February 2017. The school has been seen as a great success, particularly for new students, who receive a strong grounding in experimental and theoretical aspects of particle physics.
Outreach In 2017, CoEPP will continue its highly successful high-school programs: international masterclass and work experience week. In addition, the Centre is planning a Year 9 Science Camp for students from four key high schools in the Northern Grampians Shire in September 2017. This will be based on the dual themes of particle physics and astronomy to demonstrate how these different areas of science link and complement each other.
ANNUAL REPORT
Stakeholder and end user interactions CoEPP undertakes a broad program of interactions with stakeholders and end users. Our primary stakeholder is CERN, where a large amount of research from our Melbourne, Adelaide and Sydney nodes is undertaken. Recent initiatives within CoEPP have also begun to explore the opportunities that would be available to CoEPP and to Australian Industry through formal participation with CERN through Associate Membership. This initiative would allow Australia to bid on industrial contracts, participate in technology transfer arrangements, allow Australian citizens to be appointed to CERN staff positions and broaden our range of scientific participation within CERN.
On the political level, in October 2016 we met with Minister Hunt during the Fermilab initiative in Chicago, and in 2017 are continuing to engage with Minister Sinodinos and the Chief Scientist of Australia, Alan Finkel, with regard to enhancing the opportunities for high-energy physics research in Australia. In 2017, we will have increasing engagement with Australian industry through initiatives such as the Stawell Underground Physics Laboratory (SUPL) and the SABRE direct detection dark matter experiment, which is to be located in the laboratory. Additionally, our growing involvement with medical physics research in areas such as hadron therapy, through the University of Melbourne, continue to provide ongoing opportunities.
Other scientific initiatives, reported elsewhere in this annual report, are our formal links with Fermilab and IHEP, which provide growing worldwide awareness of the capability of CoEPP and additional opportunities for expanding our stakeholder base.
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Case study: Searching for new physics with computer vision The use of machine learning, and neural networks in particular, has a long history in particle physics, and the idea of using neural networks for quark–gluon discrimination, Higgs tagging and track identification goes back over 25 years. However, the development of efficient deep neural networks and the computing power associated with graphics processing units mean that image recognition technology has become extremely powerful, driving the resurgence in interest in these techniques. At the increased LHC collision energy, the ATLAS and CMS experiments have the ability to search for new particles at even higher masses. This is not without challenge, however, as these heavy particles produce narrow clusters of high-momentum Standard Model particles that can be difficult to resolve and separate from the vast background of similar signatures. The ATLAS and CMS detectors house calorimeters made of concentric cylindrical grids of cells, each measuring an electrical pulse proportional to the energy deposited by particles. They essentially capture three-dimensional cylindrical pictures of pixelised sums of particle energies around a proton– proton collision. The complex hierarchical learning models used to recognise objects such as written text or human faces in an image, or autonomously drive a vehicle, are therefore ideally suited to extract the information from LHC collisions that are critical in the search for new physics. These so-called deep learning methods also have the potential to identify new physical properties not yet exploited by current methods. The past decade has seen an explosion of interest in understanding the structure within these calorimeter signals created by the decay of high-momentum particles at the LHC. The ability to identify the hadronic decay products of a wide variety of particles is crucial in both the analysis of Standard Model processes and searches for new physics. It will become even more important as the LHC runs at higher energies and with future colliders on the horizon. New approaches involve the application of machine learning techniques at the forefront of computer vision. After detector signals are processed into pixelated images, deep neural networks can be trained to discriminate between a signal and background. At the University of Melbourne, Dr James Barnard, Dr Noel Dawe, Dr Matthew Dolan and CoEPP student Nina Rajcic investigated how the modelling variations across three major proton–proton collision simulation software implementations affect the performance of a deep neural network using calorimeter images created by hadronic W
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boson decays. One model included in this study was developed by Dr Peter Skands and Nadine Fischer at Monash University (Eur. Phys. J. C 76, 589). Differences in network performance were no larger than differences observed when using traditional identification variables. The published result (Phys. Rev. D 95, 014018) will help strengthen the foundation for future studies in this area.
Figure 1 Jet image generation in ATLAS detector.
Figure 2 Jet image for hadronic W boson.
Disclaimer The ARC Centre of Excellence for Particle Physics at the Terascale (CoEPP) has used its best endeavours to ensure that material contained in this publication was correct at the time of printing. Authorisation CoEPP Advisory Board and Executive Committee. April 2017. Images Courtesy of ATLAS Experiment, Casamento photography, CERN, Frank DeLaRambelya, Caroline Hamilton, Daniel Linnet, Steve Morton, Laura Vanags, Royal Society of Victoria, Fermilab, IHEP and IUPAP Secretariat. Design Biotext, Canberra
ARC CENTRE OF EXCELLENCE FOR PARTICLE PHYSICS AT THE TERASCALE
ARC Centre of Excellence for Particle Physics at the Terascale ANNUAL REPORT
2016
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