Dec. 21, 2007
UI researchers celebrate latest milestone in construction of atom smasher
University of Iowa researchers joined their U.S. and international colleagues Dec. 19 in celebrating a major construction milestone that brings them one step closer to the completion of the most powerful device ever designed to search for the basic building blocks of matter.
The event was the installation of the world's largest (six-ton) silicon tracking detector at the site of what will soon become the world's largest atom smasher: the Large Hadron Collider accelerator at CERN in Geneva, Switzerland.
The Iowa researchers take pride in the fact that they have helped develop the silicon tracking detector, specifically in the use of silicon pixel detectors, ever since UI physics professor Charles Newsom joined their group in 2005. The researchers note that their work is important because precision tracking, which will guard against damage from residual radiation that results from colliding protons, will be crucial to the search for the Higgs boson, an elementary particle predicted to exist and whose investigation is one of the goals of the project.
Yasar Onel, professor of physics in the UI College of Liberal Arts and Sciences, said that the detector is another component of the accelerator's Compact Muon Solenoid (CMS) particle detector, a device of great interest to Iowa researchers, who earlier contributed a component of their own design to the project.
Onel said that the UI particle detector, or hadronic calorimeter (HCAL), was designed, prototyped and developed at UI machine shops and became the first detector to be placed underground in the CMS collision hall in November 2006. Onel, who served as U.S. project coordinator for the task, said that the HCAL began collecting cosmic ray data in 2006, far in advance of the proton-proton collisions that will eventually take place in the CERN atom smasher.
"Our group continues to participate in remaining construction tasks as well as the commissioning and calibration of this detector," he said. "The hadronic calorimeter is crucial to the study of jets and missing energy, so correct understanding of its response is essential to early analysis efforts and the detection of signals of new physics."
Onel added that scientists don't know what they will find -- perhaps even a new physics that could change our understanding of the universe -- once the CERN accelerator becomes operational sometime in 2008. The atom smasher will use magnets to accelerate two beams of protons so that they race around a 16.5-mile oval track in opposite directions. When they meet in a head-on collision, the protons will break apart, spraying particles in different directions.
"Our goal is to search for the origin of electroweak symmetry breaking, and we expect that the accelerator will reveal hints in the form of the observation of new particles and interactions. We are involved in the search for the Higgs boson as predicted by the Standard Model and also by models of physics beyond the Standard Model," he says. "Our studies of jets and missing energy may lead us to the observation of new physics with the first CMS data, whether it appears as evidence of "Supersymmetric" particles or something entirely different."
The UI High Energy Experimental Physics group has been a part of CMS since it was approved as an experiment in 1996, with professors Onel, Ed Norbeck, Charles Newsom and Jane Nachtman; engineers Paul Debbins, Michael Miller, and Ianos Schmidt; postdoctoral research associates Ugur Akgun, Kerem Cankocak, Alexi Mestvirishvili, Lalith Perera and Taylan Yetkin; and five graduate and three undergraduate students currently active.
The U.S. Department of Energy's Fermi National Accelerator Laboratory near Chicago is the host laboratory for U.S. CMS. The CMS project includes approximately 2,300 physicists, about 500 of whom are U.S. scientists from more than 45 U.S. universities.
STORY SOURCE: University of Iowa News Services, 300 Plaza Centre One, Suite 371, Iowa City, Iowa 52242-2500
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