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University of Iowa News Release

June 23, 2004

UI Researchers Participate In Particle Physics Discovery

When scientists at the U.S. Department of Energy's Fermi National Accelerator in Batavia, Ill. recently announced the observation of a new, unexpected subatomic particle, researchers in the University of Iowa College of Liberal Arts and Sciences Department of Physics and Astronomy were a part of the celebration.

UI professor Yasar Onel and his research team, along with emeritus professor Edward McCliment, built equipment crucial to the investigation -- an M1 spectrometer that had three sets of Multi-Wire Proportional Counters (MWPC) and two sets of drift chambers. Also, UI associate professor Charles Newsom constructed an important item called a micro-strip beam silicon detector.

Onel says that the M1 spectrometer alone increased the probability of making the observation by a factor of five. "Because of the spectrometer, we were able to collect more of the charm particles that we were interested in observing," he says. "The experiment, which began in 1994, resulted in our group publishing 10 scientific journal papers and producing six doctoral and three master's degree theses. The student papers are very important for our graduate students, so this has been a very productive project."

The objective of elementary particle physics research is to observe the basic building blocks of matter, perhaps leading beyond the quarks that make up protons and neutrons within atomic nuclei and are the smallest known particles at present.

In regard to the discovery itself, Fermilab said in a June 17 news release that the new particle is a member of a family of subatomic particles called "heavy-light" mesons. The new meson, a combination of a strange quark and a charm antiquark, is the heaviest-ever observed in this family, and it behaves in surprising ways. As a rule, the more massive the meson, the shorter its lifetime before it decays into other particles; however, this heavy meson lives three times longer than its lighter relatives.

Onel says the discovery was totally unexpected. "The detector was designed to observe charmed baryon particles, but it had the ability to see charmed mesons, too."

Looking ahead, Onel says that he and his colleagues are excited to be constructing particle detectors, funded with more than $5 million from the U.S. Department of Energy and the National Science Foundation, that will be used in the $6 billion international effort to build the world's largest atom-smasher, Large Hadron Collider (LHC). The apparatus will be operational at the CERN particle physics laboratory, located on the border between France and Switzerland by 2007.

"We did a good job at Fermilab," he says. "Now we move on to CERN. We are three years away from beginning our CERN investigation, and the new machine should provide 20 years of new discoveries."

STORY SOURCE: University of Iowa News Services, 300 Plaza Centre One, Suite 371, Iowa City, Iowa 52242-2500.

CONTACTS: Gary Galluzzo, 319-384-0009,