Identified Particle Production in p+p, d+Au, and Au+Au Collisions at RHIC

Measurements of identified particle production with the PHENIX experiment at RHIC have reached a mature state, where a multitude of nuclear systems at different colliding energies have been studied. The discovery configurations of $\sqrt{s_{NN}}$ = 130 and 200 GeV Au+Au collisions have now been supplemented by additional Au+Au and Cu+Cu configurations at various energies, along with baseline p+p and d+Au runs at $\sqrt{s_{NN}}$ = 200 GeV. In this work we present a systematic study of the Cronin effect in d+Au collisions and recent results from p+p collisions. We then proceed to make a critical comparison of pion, kaon and proton production in heavy ion and baseline systems, and discuss the observed nuclear effects on hadron production.Comment: 10 pages, 6 figures, Proceedings for the 21st Winter Workshop on Nuclear Dynamics, Breckenridge, Colorado, USA, February 5-12, 200

Particle Production in Proton-Proton and Deuteron-Gold Collisions at RHIC

We try to understand recent data on proton-proton and deuteron-gold collisions at RHIC, employing a parton model approach called EPOS.Comment: Invited talk, given at SQM2004, Cape Town, South Africa, 15-20 September, 200

Jet Correlations of Identified Particles in PHENIX

Azimuthal two particle correlations at intermediate $p_{T}$ with one of the particles identified have been measured at PHENIX. Trigger ($2.5 < p_{T} < 4.0 GeV/c$) baryons and mesons show little significant difference in the number of associated particles ($1.7 < p_{T} < 2.5 GeV/c$) independent of centrality. For inclusive hadron triggers with $2.5 < p_{T} < 4.0 GeV/c$, associated fragmentation particles with $1.0 < p_{T} < 2.5 GeV/c$ show a higher baryon to meson ratio on the away side.Comment: talk given at Quark Matter 2004, 4 pages 4 figur

π/K/p\pi/K/p production and Cronin effect from p+p, d+Au and Au+Au collisions at sNN=200\sqrt{s_{NN}}= 200 GeV from the PHENIX experiment

We present results on identified particle production in p+p, d+Au and Au+Au collisions at $\sqrt{s_{NN}} = 200$ GeV at mid-rapidity measured by the PHENIX experiment. The centrality and flavor dependence of the Cronin effect in d+Au collisions is measured. The Cronin effect for the protons in d+Au is larger than that for the pions, but not large enough to account for the ``anomalous'' proton to pion ratio in central Au+Au collisions.Comment: 5 pages, 3 figures, contribution to the proceedings of the 17th International Conference on Ultra-Relativistic Nucleus-Nucleus Collisions (Quark Matter 2004

Correlations at intermediate pTp_T

Correlations among hadrons in jets produced in heavy-ion collisions are discussed in the framework of the recombination model. The basic correlation at the parton level is among the shower partons arising from kinematical constraint. The resultant correlation between hadrons at intermediate $p_T$ is amazingly rich in characteristics.Comment: 10 pages including 12 figures. Talk presented at the MIT Workshop on Correlations and Fluctuations in Relativistic Nuclear Collisions, April 200

PHENIX Highlights

Recent highlights of measurements by the PHENIX experiment at RHIC are presented.Comment: 8 pages, 9 figures. Talk at Quark Matter 200

Jet properties from π±\pi^{\pm} - h±h^{\pm} correlation in p+pp+p and dd+Au collisions at sNN\sqrt{s_{NN}} = 200 GeV

We review recent results on the charged pion - charged hadron correlation in $p+p$ and $d$ + Au collisions as measured by the PHENIX Collaboration. Properties of di-jet system, such as the jet shape, associated hadron yield per trigger pion, and the underlying event are extracted statistically from the $\pi^{\pm}-h^{\pm}$ correlation function in $\Delta\phi$ and $\Delta\eta$. For jet triggered with high $p_T$ pions ($p_T>5$ GeV/c), no apparent differences in the jet properties are seen between $p+p$ and $d$ + Au.Comment: Proceeding for Correlation and Fluctuation Workshop at MIT (April 2005), 11 pages, 17 figures, update a couple of formula

Jets as a Probe of Dense Matter at RHIC

Jet quenching in the matter created in high energy nucleus-nucleus collisions provides a tomographic tool to probe the medium properties. Recent experimental results on jet production at the Relativistic Heavy-Ion Collider (RHIC) are reviewed. Jet properties in p+p and d+Au collisions have been measured, establishing the baseline for studying jet modification in heavy-ion collisions. Current progress on detailed studies of high transverse momentum production in Au+Au collisions is discussed, with an emphasis on dihadron correlation measurements.Comment: 8 pages, 9 figures. Plenary talk given at 17th International Conference on Ultra Relativistic Nucleus-Nucleus Collisions (Quark Matter 2004), Oakland, California, 11-17 Jan 2004. Submitted to J.Phys.

Jet quenching at intermediate RHIC energies

The final state energy loss of fast partons penetrating a longitudinally expanding quark-gluon plasma of effective gluon rapidity density $dN^{g}/dy=650-800$ is evaluated and incorporated together with the multiple initial state Cronin scattering in the lowest order perturbative QCD hadron production formalism. Predictions for the neutral pion attenuation in central $Au+Au$ collisions at the intermediate RHIC energy of $\sqrt{s_{NN}}=62$ GeV relative to the binary collision scaled $p+p$ result are given. The quenching is found to be a factor of 2-3 with a moderate transverse momentum dependence and the attenuation of the away-side di-hadron correlation function is estimated to be 3-5 fold.Comment: Discussion of the different approximations to 3+1D plasma expansion and their impact on the energy loss calculation is added. The relation between the quenching of the single and double inclusive spectra is also clarified and shown in the right panel of Figure 2. 7 pages, 2 figure

Bulk properties and flow

In this report, I summarize the experimental results on {\bf bulk properties and flow} presented at Quark Matter 2004. It is organized in four sections: 1) Initial condition and stopping; 2) Particle spectra and freeze-outs; 3) Anisotropic flow; 4) Outlook for future measurements.Comment: 10 pages, 4 figures, "Rapporteur-Conference Highlights", Quark Matter 2004, Oakland, January 11-1