Smashing atoms

SCIENCE

“ Atom smashers will continue to yield vital clues into the universe’s most puzzling mysteries”

Smashing atoms

Slamming together tiny particles can uncover our universe’s biggest secrets

High-energy particle collisions are a window into the subatomic world. Creating them, however, requires some of the most complex technology on the planet. First, particle accelerators use electric fi elds to boost charged particles to almost the speed of light, ramping up their kinetic energy. In a circular collider like the Large Hadron Collider (LHC), magnets steer and focus these particles into two beams no more than two millimetres (0.08 inches) wide, travelling in opposite directions. At designated points in the heart of particle detectors, the beams cross to produce head-on collisions.

As predicted by Einstein’s famous E=mc2 , under the right conditions, mass can be transformed into energy and vice versa. And this is exactly what happens when two particles crash together. The colliding particles break in to their smallest subatomic constituents, shooting in all directions. As well as the usual suspects, some of these creations are rare, exotic particles whose very existence exposes the inner workings of our universe.

Know your particle machines

Particle physicists pick and mix different types of accelerators and colliders to do their research. Linear accelerators push particles in a straight line, whereas cyclotrons and synchrotrons set them whizzing around a circular path, building up top speeds by giving particles an extra nudge with each successive lap. Synchrotron light sources, meanwhile, take advantage of the electromagnetic radiation emitted by particles coursing around a synchrotron. Focusing this high-intensity light into a narrow beam, they can probe the molecular structure of anything from new drugs to historic paintings.

Short-lived particles such as the Higgs boson rapidly decay into other types. To determine their presence, physicists analyse the particles produced by each collision, looking for tell-tale signs. This work is accomplished thanks to advanced detectors, which identify various species of particle and record their speeds, energies and trajectories.

Particle research has shaped modern physics, providing evidence for current theories on what the universe is made of as well as the laws that govern it. In the last 50 years, colliders have glimpsed scores of previously unseen inhabitants of the subatomic world, from quarks – matter’s fundamental building blocks – to the more recent famous Higgs boson.

But such discoveries are merely the tip of the iceberg. In the decades to come, atom smashers will continue to yield vital clues into the universe’s most puzzling mysteries, from unmasking dark matter to perhaps revealing extra dimensions of space.

The LHC is currently shut for upgrades and is due to reopen in early-2015