Matter may not have exisited since Big Bang
By David Tollon
Physicists at Kent State are excited about the discovery of a new state of matter, but find the timeliness of the recent announcement a little quarky.
On February 10, physicists at CERN, the European laboratory for particle physics in Switzerland, made public the results of its five-year program on heavy-ion collision experiments.
The result is circumstantial evidence that a quark-gluon plasma has been detected. Quarks are the tiniest components of matter and gluons are what hold the quarks together. The two combine to make up more complex protons and neutrons.
This state of matter has not existed since a few microseconds after the Big Bang. Until recently, they have never been able to roam freely.
Kent State physics professor Declan Keane said that these are interesting observations that carry some weight, but the book is not closed on such findings. "There is no smoking gun evidence for a new state of matter," Keane said. "People in the U.S. are getting ready for new accelerated experiments and hope to produce more conclusive evidence."
These findings set the stage for more rigorous testing soon to begin at Brookhaven National Laboratory's Relativistic Heavy Ion Collider, RHIC, in New York.
Gabor David, staff scientist at Brookhaven, gave a seminar Friday, in the physics department, responding to the new announcement and the future experimentation for Brookhaven. "CERN's evidence is not enough to prove beyond a reasonable doubt the creation of a quark-gluon plasma," David said. "RHIC will find the quark-gluon plasma and measure its properties."
David said that Brookhaven has found methods to minimize sources of error and hopes to piece together the findings at CERN with its own to directly observe the plasma far better than what has been discovered.
CERN's press release states how these findings were achieved:
* Heavy Ion program collided lead ions to create immensely high densities to break down the forces that confine binded quarks in more complex particles.
* A high beam of lead ions was accelerated in CERN's Super Proton Synchrotron and crashed into targets inside seven different experimental detectors. The collisions created temperatures more than 100,000 times the internal temperature of the sun, and also created energy densities which have never been reached in laboratory experiments. Data was collected giving evidence that a new form of matter had been created.
Although the temperatures, densities and observations from the seven experiments approached the values where theory predicts the quark-gluon plasma to form, when analyzed independently, no single experiment is definitive. But when the results are collaborated, they provide circumstantial evidence that a quark-gluon plasma may have formed.
Kent State physics professor George Fai said that the results are, indeed, circumstantial, and that none of these experiments, when looked at individually, are proof-positive. "If you interpret the large set of experiments as a whole, you can see they are consistent to being at the threshold," Fai said. The RHIC experiments, expected to begin this summer, will provide much higher collision energies and temperatures using gold ions. This will allow the quark-gluon plasma to linger long enough for direct observations that were not possible with the CERN experiments.