case study 1

Student collaboration across nodes and physics sub-disciplines

A collaboration that unites astrophysics with particle physics has offered valuable opportunities for two Centre members to gain new skills and knowledge.

Completing PhD students, Grace Lawrence (SUT) and Madeleine Zurowski (UoM), are working together to explore corrections and uncertainties in the calculation of dark matter direct detection rates.

The two aim to take the detailed simulated velocity distributions at various points in the galaxy that Grace has generated, and combine them with detector effects, and more complex models for dark matter interactions than are typically assumed.

The two decided to collaborate after Maddy heard Grace’s talk about her work on velocity distributions, and comparing them to the standard assumptions (called the Standard Halo Model).

The talk sparked Maddy’s interest.

“One of the things that I think is cool about Grace’s simulations is that they revealed a lot of substructure at various velocities. Even though this didn’t create significant deviations from the results you get with the simple spin independent, elastic dark matter model, I have studied other dark matter models that can vary a lot more with small changes in velocity, and so was interested in how assuming Grace’s velocity distributions would change the results.”

Grace brings a specialised understanding of astrophysics to the partnership, while Madeleine’s background is in particle physics and detectors.

“Combining our respective specialities, we investigated the expected annual modulation signal for our Milky Way using the realistic velocity distribution functions from my work, and the particle physics rate calculations from Maddy,” said Grace.

“Additionally, we have plans to explore the unique ‘turnover mechanism’, which sees the complete reversal of the annual modulation phase, from both the astrophysics and particle physics perspectives.”

The two plan to produce research papers resulting from their work, and have discussed combining the code for computing direct detection rates under different assumptions that they created independently.

“People talk about the interaction/observation rate as having an astrophysics and a particle physics component, and I think our expertise matches pretty well with that.”

The collaboration has provided Grace with new skills and knowledge in an area in which she was less familiar.

“Originating from an Astronomy background, working with Maddy has given me a new understanding of the complex detector effects than come into play for differential rate calculations, in particular for the SABRE South experiment, as well as a broadened insight into how important the combination of astrophysics and particle physics is for the future of dark matter science.”

Similarly, the collaboration has offered Madeleine a better understanding of what the velocity distribution physically corresponds to, as well as providing a different focus to her usual work.

“It’s been very enjoyable working on something a bit more abstract than dealing with all the details of designing and assessing a single detector!”

Along with gaining new knowledge, the two have gained enjoyment from the experience of working together, across nodes and areas of specialism.

They will continue with the collaboration from their new roles, Madeleine as a postdoctoral researcher at the University of Toronto, with a continued involvement as a Centre Associate Investigator with the SABRE South experiment, and Grace has recently submitted her PhD thesis, which is currently under examination. She hopes to undertake a dark matter post-doctoral research position.

In the future they plan to seek further opportunities to collaborate together and with members from other nodes.