Highlights from BNL-RHIC

Abstract

Recent highlights from Brookhaven National Laboratory and the Relativistic Heavy Ion Collider (RHIC) are reviewed and discussed. Topics include: Discovery of the strongly interacting Quark Gluon Plasma (sQGP) in 2005; RHIC machine operation in 2011 as well as latest achievements from the superconducting Magnet Division and the National Synchrotron Light Source II project. Highlights from QGP physics at RHIC include: comparison of new measurements of charged multiplicity in A+A collisions by ALICE at the LHC to previous RHIC measurements; Observation of the anti-alpha particle by the STAR experiment; Collective Flow, including the Triangular Flow discovery and the latest results on v3; the RHIC beam energy scan in search of the QCD critical point. The pioneering use at RHIC of hard-scattering as a probe of the sQGP will also be reviewed and the latest results presented including: jet-quenching via suppression of high pT particles and two particle correlations; new results on fragmentation functions using gamma-hadron correlations in p-p and Au+Au collisions; comparison of jet imbalance in A+A relative to p-p collisions measured by PHENIX using pizero-hadron correlations to CMS measurements with reconstructed jets; first measurement by PHENIX of anisotropic flow of direct photons in the thermal range 1< pT < 3 GeV/c, with v2 as large as that of pions; a review of the equality of the suppression of inclusive pi0 (from light quarks and gluons) and direct-single electrons (from the decay of heavy quarks) in the transverse momentum range 4< pT < 9 GeV/c, at RHIC (now also seen with reconstructed charm mesons by ALICE at the LHC) which disfavors a radiative explanation of suppression and leads to a fundamental question of whether the Higgs boson gives mass to fermions.