10 pages, 9 figures. Invited talk at 5th International Workshop on Critical Point and Onset of Deconfinement - June 08 - 12 2009 Brookhaven National Laboratory, Long Island, New York, USA
PHENIX plans for low energy running are presented. Current detector setting makes it possible to measure dielectron spectra down to sqrt(s_NN)=39GeV, and photon/high pT hadron spectra down to below sub-injection energy (sqrt(s_NN)=5-10GeV). The upgrade of the trigger scheme after the installation of VTX detector will enable PHENIX to fully explore the sub-injection energy regime, starting 2011.
In this paper we show azimuthal particle correlations in three different small-system collisions with different intrinsic initial geometries. The simultaneous constraints of $v_2$ and $v_3$ in $p/d/^3$He$+$Au collisions definitively demonstrate that the $v_n$'s are correlated to the initial geometry. In addition, we find that hydrodynamical models which include QGP formation describe simultaneouly the elliptic and triangular flow data in a statistically acceptable manner in all three systems.
Heavy flavor production is an ideal tool to study the properties of the Quark Gluon Plasma (QGP). The heavy flavor production at the Relativistic Heavy Ion Collider (RHIC) has its unique kinematic coverage and different production mechanisms from the Larger Hadron Collider (LHC) measurements. Heavy flavor products created in heavy ion collisions experience the whole evolution of nuclear medium. It's critical to measure both open and closed heavy flavor products in different collision systems to isolate cold/hot nuclear medium effects and initial/final state interactions. We report recent heavy…
The measurement of quarkonia production in relativistic heavy ion collisions provides a powerful tool for studying the properties of the hot and dense matter created in these collisions. To be really useful, however, such measurements must cover a wide range of quarkonia states and colliding species. The PHENIX experiment at RHIC has successfully measured J/psi, psi-prime, chi_c and Upsilon production in different colliding systems at various energies. In this talk I will present recent results from the PHENIX collaboration on charmonium production in d+Au, Cu+Au and U+U collisions at 200 GeV/…
Over the last decade it has been established that a quark-gluon plasma (QGP) is formed in ultrarelativistic A+A collisions at RHIC energies. In recent years, detector upgrades have enabled the detailed study of this hot and dense matter. Important probes, among others, are direct photons and heavy flavor observables. Although the RHIC d+Au program was originally undertaken to study initial state and cold nuclear matter effects, recent measurements at both RHIC (d+Au) and the LHC (p+Pb) have found evidence for collective phenomena in these small systems.
High $p_{\rm T}$ hadrons in the small systems of $d/^3$He+Au and $p$+Al/Au collisions have been measured at the midrapidity ($|η|<0.35$) as well as at the forward and backward rapidities ($1.2<|η|<2.4$) at $\sqrt{s_{NN}}$=200GeV. A clear system and centrality ordering in the $R_{p/d/{\rm HeA}}$ was observed for midrapidity $π^0$ production. Hadron $R_{\rm cp}$ as a function of rapidity in forward and backward regions show an opposite trend to what HIJING++ predicted. Together with the difference of $R_{\rm cp}$ in $p$+Al/Au collisions, the observation can be understood consistently with the me…
Charged pion two-particle correlation functions were measured in 0-30% centrality 200 GeV Au+Au collisions with the PHENIX experiment at RHIC. The measured correlation functions can be statistically well described based on the assumption of Levy-shaped source distributions. In this proceedings paper we present the Levy parameters of the measured correlation functions: correlation strength parameter lambda, Levy index alpha and Levy scale parameter R as a function of pair transverse mass mT, in 31 bins from 228 to 871 MeV, separately for positive and negative pion pairs. We discuss the physical…
Heavy flavor and quarkona production are important hard probes to test the Quantum Chromodynamics (QCD) and measure the properties of the Quark Gluon Plasma (QGP) created in high energy heavy ion collisions. The new PHENIX mid- and forward-rapidity silicon vertex detectors provide precise Distance of Closest Approach (DCA) determination, allowing charm and bottom yields identification, and improve di-muon mass resolution for charmonia studies. The relative $ψ(2S)$ over $J/ψ$(1S) yields measured in $p$+$p$, $p$+Al and $p$+Au data at $\sqrt{s}=$200 GeV help us to understand final state effects o…
