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New Substance Reflect's Universe's Beginnings


UCR Researchers Part of Brookhaven National Laboratory Team That Discovered “Perfect” Liquid Thought to be What Existed When the Universe Began

New state of matter more remarkable than predicted — raising many new questions

(April 26, 2005)

A computer image generated from data collected at the PHENIX detector during RHIC's second run cycle.Reconstructed tracks (in green) point towards the location of the collisions. The beam path is shown in red.

A computer image generated from data collected at the PHENIX detector during RHIC's second run cycle.Reconstructed tracks (in green) point towards the location of the collisions. The beam path is shown in red.

RIVERSIDE, Calif. — www.ucr.edu — Researchers at the University of California, Riverside were part of a team using a giant “atom smasher” at Brookhaven National Laboratory to uncover a unique new state of hot, dense matter, a nearly perfect liquid, which resembles what physicists believe to have existed immediately after the Big Bang.

Two UC Riverside physicist, Kenneth Barish, and Richard Seto, were among scientists contributing to the groundbreaking research. Using the U.S. Department of Energy’s Relativistic Heavy Ion Collider (RHIC) — a giant “atom smasher” — the team of scientists collided gold ions at nearly the speed of light to create the new state of hot, dense matter consisting of subatomic particles.

Scientists worked in four groups named PHENIX, BRAHMS, PHOBOS and STAR at the New York laboratory. Barish and Seto, who specialize in experimental nuclear and particle physics, played leading roles in the PHENIX collaboration, an acronym for Pioneering High Energy Nuclear Interaction Experiment. The group used RHIC to collide the ions, while the detector PHENIX was the device used to examine the debris formed in the collisions. In a sense, PHENIX was the camera that took X-ray photographs of the collisions. The scale of the project was enormous — PHENIX is roughly the size of a gymnasium, cost $100 million and took roughly 1 billion photographs over six months.

UCR is a founding member of the collaboration and has played a leadership role since its beginning.

“We have built one of the main subsystems, designed and built specialized electronics designed to pick out the most interesting events and our group analyzed data-prepared papers that are a basis for the conclusions in a preliminary summary outlining the first years of operation,” explained Barish.

In addition to professors Barish and Seto, the UCR group included 10 postdoctoral fellows, six graduate students, six undergraduate students and Professor Emeritus of Physics S.Y. Fung. The group was funded by the U.S. Department of Energy Office of Science, which is headed by former UCR Chancellor Raymond Orbach.

The working groups have noted that some of the observations at RHIC fit with the theoretical predictions for a quark-gluon plasma (QGP) — the type of matter thought to have existed just microseconds after the Big Bang. The Relativistic Heavy Ion Collider forms this matter through the acceleration of gold ions colliding head-on at nearly the speed of light.

The PHENIX group observed the resulting impact by focusing on the routes taken by thousands of particles produced in the crash of ions. What the researchers found surprised them all — the subatomic particles produced in the collision tended to move collectively instead of randomly.

Scientists refer to this phenomenon as “flow” since it has the properties of fluid motion. However, unlike ordinary liquids, in which individual molecules move about randomly, the hot matter formed from the collisions seemed to move somewhat like a school of fish that react as one entity. Temperature of the liquid has reached to 150,00 times hotter than the center of the sun.

The announcement came at the conference for the American Physical Society, which was held in Tampa, Fla. on April 18.

Describing the fluid motion as nearly “perfect” — meaning it has a very low viscosity and flows with essentially zero resistance — the discovery has important implications for the future of physics.

“This is really the beginning of an age of discovery,” says Barish. “We are now in a position to make truly exciting discoveries as we learn more detailed properties of this matter.”

The University of California, Riverside (www.ucr.edu) is a doctoral research university, a living laboratory for groundbreaking exploration of issues critical to Inland Southern California, the state and communities around the world. Reflecting California's diverse culture, UCR's enrollment has exceeded 21,000 students. The campus opened a medical school in 2013 and has reached the heart of the Coachella Valley by way of the UCR Palm Desert Center. The campus has an annual statewide economic impact of more than $1 billion.

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