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University of Iowa News Release


March 23, 2009

UI physicists help find evidence for new particle of matter

Scientists at the U.S. Department of Energy's (DOE) Fermi National Accelerator Laboratory in Batavia, Ill., recently found evidence of an unexpected particle whose unusual characteristics may reveal new ways that major building blocks of matter, called quarks, can combine to form matter.

The scientists -- including a group from the University of Iowa -- say that quarks comprise other particles such as mesons, which are made of a quark-antiquark pair, and baryons, which are composed of three quarks. At present nobody knows what the new particle, dubbed Y(4140) for its measured mass of 4140 Mega-electron volts, is made of.

At the very least, the discovery of the particle has excited researchers, said UI associate professor of physics Jane Nachtman, whose UI group led the way in analyzing the particle dataset resulting from the CDF (Collider Detector at Fermilab) experiment.

"We are very excited by this new result and will be adding more data and expanding our efforts to more search channels and studies of other properties of the Y(4140)," said Nachtman. "This is an area where unexpected physics has been showing up in recent years, and we want to be a part of uncovering the big picture of how these particles fit together."

UI postdoctoral fellow Kai Yi said, "We are eager to continue and extend our efforts on this topic using more data collected at CDF." Nachtman added that Yi's experience in analyzing the data from the SLAC B-factory (Stanford Linear Accelerator Center), as well as his doctoral work on CDF, enabled the UI team to quickly and precisely isolate the new signal in the CDF data.

In addition to Nachtmam and Yi, the UI team includes UI postdoctoral fellow Kwangzoo Chung. All are working in collaboration with Fermilab scientists.

Yasar Onel, professor of physics in the UI College of Liberal Arts and Sciences, said: "This is a great achievement by UI-High Energy Physics group member Professor Jane Nachtman and her post-docs on the CDF experiment at Fermilab. This group is also part of our LHC research team with the CMS experiment and are already contributing to the CMS Hadron Calorimetry trigger, particularly the HF Forward detectors that were proposed, designed and developed at UI. We are hoping for many more discoveries like this by our group with the CMS detector at the LHC."

Onel is the head of the UI CMS (Compact Muon Solenoid) group working on particle detection at the Large Hadron Collider (LHC) at CERN in Geneva, Switzerland.

The Y(4140) observation currently is the subject of an article submitted by CDF researchers to the journal Physical Review Letters.

The Y(4140) particle is the newest member of a family of particles of similar unusual characteristics observed in the last several years by experimenters at Fermilab's Tevatron as well as at KEK laboratory in Japan and at DOE's SLAC National Accelerator Laboratory in California.

CDF is an international experiment of about 602 physicists from 63 institutions in 13 countries. Funding for CDF comes from DOE's Office of Science, the National Science Foundation, and a number of international funding agencies.

CDF collaborating institutions and other information can be found at:

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

MEDIA CONTACT: Gary Galluzzo, 319-384-0009,