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John Hill, Physics, (515) 294-6580
Bridget Bailey, ISU News Service, (515) 294-6881


AMES, Iowa -- Thanks in part to a device a team of Iowa State scientists helped to develop, we may finally be able to answer a fundamental question of science: What was the universe like at the beginning of time?

Fifteen billion years ago, just a fraction of a second after the "Big Bang," the universe was believed to have been a million times hotter than the surface of the sun, millions of times denser than the heaviest metals, and very small. Because of the high temperatures, the individual basic elements that make up matter--protons and neutrons--didn't even exist. The universe was composed of particles called quarks and gluons, the basic constituents of protons and neutrons.

On June 18, scientists at Brookhaven National Laboratory in Long Island, N.Y., announced that the hottest, densest matter ever observed had been created. John Hill, Iowa State University professor of physics and astronomy, said some scientists believe that this matter is a quark-gluon plasma, a form of matter believed to have existed for only a few millionths of a second after the "Big Bang," and therefore similar to matter present at the birth of the universe. Scientists believe that the structure of the universe today was influenced by the processes by which the quark-gluon plasma cooled.

This new form of matter was created through a series of experiments at Brookhaven's new accelerator, the Relativistic Heavy Ion Collider (RHIC), where gold nuclei traveling at nearly the speed of light collide. Iowa State physics professors Hill, John Lajoie, Craig Ogilvie, Marzia Rosati and Fred Wohn, along with students, engineers and other members of the ISU research community, built the first-level trigger for the $100 million PHENIX detector at the RHIC facility. The trigger helps scientists select the few head-on collisions of gold nuclei most likely to produce quark-gluon plasma. Without the trigger, the PHENIX detector could not efficiently select these events, Professor Lajoie noted.

Hill said scientists are excited about a breakthrough related to the behavior of "jets" -- quarks materializing into swarms of high-energy, sub-atomic particles. Lajoie and Ogilvie, who led part of the analysis of the jet-producing collisions, pointed out that the observed disappearance of some jets strongly suggests the brief formation of the quark-gluon plasma.

Ogilvie said that experiments to be conducted in 2004 may help researchers determine whether the new form of matter observed is quark-gluon plasma.

The Iowa State group is one of the largest U.S. university research teams carrying out research at PHENIX. Their work has been funded by a three-year grant from the U.S. Department of Energy, Hill said.

"This is a world-caliber research effort. It has unlimited potential to learn more about the forces that hold matter together and the nature of the universe at the moment of its creation," Rosati said.


Editors: For more information, visit

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