# Quark Matter 2012

12-18 August 2012
US/Eastern timezone

## Search for QCD Phase Transitions and the Critical Point Utilizing Particle Ratio Fluctuations and Transverse Momentum Correlations from the STAR Experiment.

14 Aug 2012, 16:45
20m
Diplomat ()

### Diplomat

Oral Presentation Correlations and fluctuations

### Speaker

Mr Prithwish Tribedy (for the STAR collaboration)

### Description

Dynamical fluctuations in globally conserved quantities such as baryon number, strangeness, charge, and isospin are suggested to carry information about the de-confinement and chiral phase transitions. An observation of enhanced dynamical fluctuations or non-monotonic behavior of transverse momentum correlations as a function of colliding energy might indicate the system has probed the predicted QCD critical point. The STAR experiment has performed a comprehensive study of the energy and charge dependence of dynamical particle ratio ($K/\pi$, $p/\pi$, and $K/p$) fluctuations, net-charge fluctuations, and transverse momentum correlations in the STAR TPC at mid-rapidity, as well as neutral-charge pion fluctuations at forward rapidity. The charge dependence of particle ratio fluctuations exhibit differences between same and opposite sign dynamical particle ratio fluctuations compared to inclusive charged dynamical fluctuations. Neutral-charge pion fluctuations at forward rapidity are measured by detecting neutral pion decay photons in the Photon Multiplicity Detector and charged pions by the Forward Time Projection Chamber, which cover the same pseudorapidty region. The centrality, energy, and charge dependence from new measurements of the fluctuation observables $\nu_{dyn}$ and $r_{m,1}$ and the energy dependence of transverse momentum correlations from $\sqrt{s_{NN}}$ = 7.7-200 GeV Au+Au collisions will be presented. These results are also compared to theoretical predictions from models such as HIJING and UrQMD.

### Primary author

Mr Prithwish Tribedy (for the STAR collaboration)

 Slides

Paper files: