Measurement of Open Heavy Flavor Production with Single Muons in p+p and d+Au Collisions at RHIC

Heavy flavor production in hadronic collisions is dominated by gluonic processes and so is a sensitive probe of the gluon structure function in the nucleon and its modification in nuclei. A study of heavy flavor production in p+p and d+Au collisions in various kinematic regions presents an opportunity to probe cold nuclear medium effects; parton shadowing, color glass condensate, initial state energy loss, and coherent multiple scattering in final state interactions. The PHENIX muon arms cover both forward and backward directions in the rapidity range of $1.2 < |\eta| < 2.4$. We investigate single muon production from open heavy flavor and light mesons decay in p+p and d+Au collisions at forward and backward rapidity.Comment: Strangeness in Quark Matter, 2006, UCL

Excitation functions of baryon anomaly and freeze-out properties at RHIC-PHENIX

The intermediate $p_T$ region (2 - 5 GeV/$c$) in central Au+Au collisions at RHIC has a rich physics content. The (anti)proton to pion ratio at the intermediate $p_T$ gives us a powerful tool to investigate the bulk properties of the hot and dense matter created at RHIC and their hadronization processes. We present the preliminary results of identified charged hadron spectra at the lower beam energies at RHIC. The excitation function of (anti)proton to pion ratios from SPS to RHIC are shown. We also discuss the onset of the baryon enhancement at the high energy heavy ion collisions.Comment: 4 pages, 3 figures, Quark Matter 2006 conference proceeding

Some thoughts on di-jet correlation in Au + Au collisions from PHENIX

PHENIX has measured the two particle azimuth correlation in Au + Au at $\sqrt{s}$ = 200 GeV. Jet shape and yield at the away side are found to be strongly modified at intermediate and low $p_T$, and the modifications vary dramatically with $p_T$ and centrality. At high $p_T$, away side jet peak reappears but the yield is suppressed. We discuss the possible physics pictures leading to these complicated modifications.Comment: 3 pages, 2 figures. Contributed talk at PANIC '05 conference, Santa Fe, NM, Oct24-28, 200

Scaling properties of azimuthal anisotropy of mesons and baryons at RHIC

Detailed measurements of the azimuthal anisotropy (\v2) for identified charged particles are reported as a function of transverse momentum ($p_T$) and centrality for Au+Au collisions at \sqrtsNN = 200 GeV. The measurements indicate clear evidence for eccentricity and particle flavor scaling over a broad range of centralities and transverse rapidity $y_T$, indicating a hydrodynamical origin of the fine structure of azimuthal anisotropy at RHIC. The observed scaling supports the picture of a suddenly hadronizing (recombining) fluid of quarks. An apparent breaking of flavor scaling at relatively large values of $y_T$ points to an important change in the mechanism for particle emission.Comment: 21St Winter workshop on Nuclear Dynamic