VU Physics and Astronomy Colloquium

Friday, April 20, at 3:30 PM in NSC 221. Join us for refreshments in the Planetarium at 3:10 PM.

"Observation of antimatter He4 nucleus at the STAR experiment at RHIC"


Dr. Don Koetke, Department of Physics & Astronomy, Valparaiso University


Observations of antimatter date back many decades beginning with the anti-electron (positron) in 1932.  The discovery of the anti-proton and anti-neutron were next.  Then, as new experimental facilities became available, anti-nuclei were discovered beginning with the lightest, the deuteron.  The most recent discovery required the unique facilities at the Relativistic Heavy Ion Collider at RHIC where the STAR collaboration made the first discovery of the anti-alpha particle.  (The alpha particle is the nucleus of He-4.)  This discovery made national and international news and was featured in both Science and Nature.

This talk will explain how the experiment was performed in the context of a large collaboration and it will examine the importance of this discovery for nuclear physics, for the study of very high temperature matter, and issues relating to the matter-antimatter asymmetry in the universe.