Particle crashers

September 9, 2008

For a team of UA scientists who helped design a key component of the world's largest physics experiment, this week should prove to be a smashing good time.

After years of helping to plan and design the world's largest particle collider, the University of Arizona physicists will watch on Wednesday as the Large Hadron Collider shoots beams of some of the smallest particles known to science around a 17-mile track buried below Switzerland and France.
Careening at speeds close to that of light, the particles will collide and shatter into minuscule pieces, potentially providing scientists with a glimpse into what makes up the fundamental building blocks of the universe.
The experiment also will set the universal clock back to just after zero, creating an environment similar to the big bang.
And though the experiment will mimic the time period immediately after the origins of the universe, the collision will be much less destructive.
There to measure the moment of impact will be a suite of sensors built at the UA.
As one of six experiments on the collider, the Atlas detector — which includes components from researchers around the world, in addition to the UA — essentially acts as a giant recorder, said Elliott Cheu, a physics professor who helped design one of the experiment's sensors.
By gauging how far certain particles travel from the impact area, Cheu said scientists will be able to understand their energy levels and momentum, as well as being able to reconstruct the collision.
Cheu, along with UA President and physics professor Robert Shelton, will give a public talk on campus on Wednesday about the collider and the UA's involvement.
Though other particle colliders have conducted similar tests, the Large Hadron Collider will smash particles together at speeds scientists have never attempted, Cheu said.
Combing through the submicroscopic-impact debris, physicists will look for unknown and theoretical particles as they attempt to learn more about what creates matter, said Kenneth Johns, another physics professor involved in the project.
""Much of the universe is composed of dark matter, and nobody knows what that is,"" he said. ""We don't understand a majority of what's occurring around us.""
Another goal is to test whether models used to describe particles and their behavior are accurate.
It's also possible that the results will yield a new fundamental theory of matter that has yet to be discovered, Johns said.
And though models and theories exist that predict what could occur, scientists don't know exactly what they'll find when the particles start flying, said John Rutherfoord, a UA physics professor and lead designer of one of Atlas' sensors.
That's part of the reason the roughly 20 UA scientists and students working on the project are eagerly awaiting the first collision, Johns said.
""The discovery potential of this experiment is incredibly high,"" he said.
(Source: Arizona Daily Star)