Heavy Flavor Physics in PHENIX

Abstract

Heavy quarks are good probes of the hot and dense medium created in relativistic heavy ion collisions since they are mainly generated early in the collision and interact with the medium in all collision stages. In addition, heavy flavor quarkonia production is thought to be uniquely sensitive to the deconfined medium of the Quark Gluon Plasma (QGP) through color screening. Heavy quark production has been studied by the PHENIX experiment at RHIC via measurements of single leptons from semi-leptonic decays, in both the electron channel at mid-rapidity and in the muon channel at forward rapidity. Large suppression and azimuthal anisotropy of single electrons have been observed in Au+Au collisions at GeV. These results suggest a large energy loss and strong flow of the heavy quarks in the hot, dense matter. The PHENIX experiment has also measured J/ψ production in p + p, d+Au, Cu+Cu, and Au+Au collisions at energies up to GeV. In central Au+Au at 200 GeV, more suppression is observed at forward rapidity than at central rapidity. This can be interpreted either as a sign of quark recombination, or as a hint of additional cold nuclear matter effects. Selected PHENIX results on open heavy flavor and heavy quarkonia production in p + p, d + Au, Cu+Cu, and Au+Au collisions are presented. The status of the recent PHENIX upgrade of the central Silicon Vertex Tracker (VTX) and its performance are elucidated.