Zooming in on the Quark Gluon Plasma

Abstract

Over the last thirty years, heavy ion experiments have recorded a wealth of data ranging from collisions of nuclei from S N N = 2 GeV up to the highest energy of 200 GeV as provided by the Relativistic Heavy Ion Collider, RHIC. It is at these high energies that the predictions of QCD come into play and new phenomena are sought that may illuminate our view of the basic structure of matter. Measurements at RHIC have revealed compelling evidence for the existence of a new form of nuclear matter at extremely high densities and temperatures. This medium allows for the predictions of QCD to be tested, and new phenomena explored, under conditions where the relevant degrees of freedom, over nuclear volumes, are expected to be those of quarks and gluons, rather than of hadrons. This is the realm of the quark gluon plasma. However, detailed analyses of the data also make it clear that this hot, dense medium has properties that are surprising, and not yet fully understood in terms of the early expectations for the quark gluon plasma. In this talk I give a brief review of the major findings and discuss the current understanding of the state of matter created.