Berkeley scientists discover heavy antiparticle
The STAR CollaborationKatie Bender talks about the discovery made 5 months ago by The STAR Collaboration.
Tuesday, April 26, 2011
Category: News > University > Research and Ideas
In an experiment that recreated the atmospheric conditions of the first few milliseconds of the Big Bang, about 30 Berkeley scientists contributed to the discovery of the heaviest antiparticle ever found, five months ago.
About 25 scientists at the Lawrence Berkeley National Laboratory and four from the Space Sciences Laboratory at UC Berkeley, in collaboration with the STAR experiment - an experiment located at the Relativistic Heavy Ion Collider at the Brookhaven National Laboratory in New York - all played a part in the discovery of antihelium-4. Their results were published in the scientific journal Nature on Sunday.
STAR, which stands for Solenoidal Tracker at RHIC, is an experiment funded by the U.S. Department of Energy that aims to conduct heavy ion research, colliding as many particles together as possible, according to STAR collaborator Hans Georg Ritter from Lawrence Berkeley National Lab.
Ritter said the discovery of antihelium-4 was a byproduct of STAR's ongoing research.
"Basically, we try to reconstruct the exact state of the universe at the earliest stage after the Big Bang ... and try to understand what happened," Ritter said.
According to STAR collaborator Hank Crawford of the Space Sciences lab, an equal amount of matter and antimatter were created and dispersed into the newly formed universe when the Big Bang occurred billions of years ago. He said that although it may seem like Earth would have encountered some of this antimatter, it has not yet been discovered here in a natural state.
"It should have survived through the Big Bang and be flying around somewhere," Crawford said.
The STAR experiments are conducted within a cylinder at the Brookhaven lab in Upton, New York. The cylinder is filled with methane gas, which allows the scientists to track the particles and analyze their movements and changes after the experiment via 3-D imaging.
The Big Bang conditions were created by colliding gold nuclei together at rapid speeds, which, according to Crawford, essentially breaks the skin of the nuclei and leads to the possibility of making new types of particles.
"By recreating 'little bangs,' we have a shot at finding new kinds of phenomena," Crawford said.
However, the STAR experiment is ongoing, and the antihelium-4 discovery was just one among many anticipated findings.
Ritter said the experiments will continue, and the findings made thus far will only trigger more questions.
"It is important to understand where we come from and what the universe is made of," Ritter said.
Contact Katie at [email protected]
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