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Big bang
Five Iowa State researchers play key role in creating matter similar to that existing
at birth of universe.
- Sometime during a recent experiment at the Brookhaven National Laboratory
in Long Island, N.Y., something amazing happened.
During that experiment the hottest, densest matter ever observed was created,
recreating conditions a fraction of a second after the birth of the universe
in the "Big Bang."
Only no one knew about it at first.
"It's not just one moment of time that we can pinpoint," said
John Lajoie, associate professor, one of five Iowa State Department of Physics
and Astronomy faculty members involved with the project.
After the series of experiments was completed, researchers looked over the
vast amount of data obtained. It was then that it was discovered that they
might have determined what the universe was like at the beginning of time.
Scientists believe that just a fraction of a second after the "Big
Bang," the universe was a million times hotter than the surface of
the sun, millions of times denser than the heaviest metals, and very small.
Because of these conditions, 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," said John Hill, professor
of physics and astronomy.
Hill says that some scientists believe that the matter created at the recent
Brookhaven experiment is a quark-gluon plasma, a form of matter that scientists
believe existed only a few millionths of a second after the "Big Bang."
"The experiment was replicated in reverse," said Craig Ogilvie,
associate professor. "After the ‘Big Bang’ the universe started
cooling down. In this experiment we heated up two pieces of matter as hot
as we could, bringing us as close as we could to the start of the universe."
The experiments were conducted at Brookhaven National Laboratory's new accelerator,
the Relativistic Heavy Ion Collider (RHIC) where gold nuclei traveling at
nearly the speed of light collide. Besides Lajoie, Hill and Ogilvie, Iowa
State associate professor Marzia Rosati and Fred Wohn, emeritus professor,
along with students, engineers and other members of the Iowa State research
community, are involved in the project.
Lajoie, Wohn and Hill 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 the quark-gluon
plasma. Without the trigger, the PHENIX detector could not effectively select
these events.
Lajoie and Ogilvie also led part of the analysis of a breakthrough related
to the behavior of "jets" which are quarks materializing into
swarms of high-energy, sub-atomic particles. They concluded that the observed
disappearance of some jets strongly suggested the brief formation of the
quark-gluon plasma.
Ogilvie and Rosati both say that this latest discovery is just the beginning
for the PHENIX project, one that Hill, Wohn and others have been working
on since 1991. Future experiments may help researchers further confirm whether
the new form of matter observed is quark-gluon plasma.
"We can now turn to study its (the new matter's) properties and see
what the early universe did," Ogilvie said.
"This is a world-caliber research effort," Rosati said. "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."
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 series
of three-year grants from the Department of Energy.
More information on the PHENIX detector and the RHIC accelerator can be
found on the web at www.phenix.bnl.gov.
John Lajoie, Marzia Rosati, John Hill and Craig Ogilvie
Around LAS
September 8-21, 2003
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