For over two decades, researchers at the Relativistic Heavy Ion Collider (RHIC) have mapped the phase diagram of QCD matter. Signatures of a quark-gluon plasma (QGP) phase created in high-energy Au+Au collisions have been observed, and the evolution of these QGP signatures tracked with varying collision energy. Yet one of the large unanswered questions of the RHIC experimental program is whether there is a critical point in the QCD phase diagram, as many models predict there should be. Recent fixed-target and collider data collected by the STAR experiment are being used to search for fluctuations in the number of protons observed in heavy-ion collisions, as such fluctuations are predicted in the vicinity of a critical point. The current status of the critical point search will be presented, along with a discussion of what was learned from STAR’s most recent data.
Host: Youqi Song