Nuclear modification factor in an anisotropic {\em Quark-Gluon-Plasma}

Abstract

We calculate the nuclear modification factor ($R_{AA}$) of light hadrons by taking into account the initial state momentum anisotropy of the quark gluon plasma (QGP) expected to be formed in relativistic heavy ion collisions. Such an anisotropy can result from the initial rapid longitudinal expansion of the matter. A phenomenological model for the space time evolution of the anisotropic QGP is used to obtain the time dependence of the anisotropy parameter $\xi$ and the hard momentum scale, $p_{\mathrm{hard}}$. The result is then compared with the PHENIX experimental data to constrain the isotropization time scale, ${\tau }_{\mathrm{iso}}$ for fixed initial conditions (FIC). It is shown that the extracted value of ${\tau }_{\mathrm{iso}}$ lies in the range $0.5\le {\tau }_{\mathrm{iso}}\le 1.5$. However, using fixed final multiplicity (FFM) condition does not lead to any firm conclusion about the extraction of the isotropization time. The present calculation is also extended to contrast with the recent measurement of nuclear modification factor by ALICE collaboration at $\sqrt{s}=2.76$ TeV. It is argued that in the present approach, the extraction of ${\tau }_{\mathrm{iso}}$ at this energy is uncertain and, therfore, refinement of the model is necessary. The sensitivity of the results on the initial conditions has been discussed. We also present the nuclear modification factor at LHC energies with $\sqrt{s}=5.5$ TeV.

18 pages, 9 eps figures, Accepted for publication in Physical Review C

References in corpus (15)

• Centrality dependence of the charged-particle multiplicity density at mid-rapidity in Pb-Pb collisions at $\sqrt{s_{\mathrm{NN}}}$ = 2.76 TeV
• Suppression of charged particle production at large transverse momentum in central Pb-Pb collisions at $\sqrt{s_{\mathrm{NN}}}=2.76$ TeV
• Charged-particle multiplicity density at mid-rapidity in central Pb-Pb collisions at $\sqrt{s_{\mathrm{NN}}}$ = 2.76 TeV
• Common Suppression Pattern of eta and pi^0 Mesons at High Transverse Momentum in Au+Au Collisions at sqrt(s_NN) = 200 GeV
• The heavy-quark potential in an anisotropic plasma
• Pre-equilibrium dilepton production from an anisotropic quark-gluon plasma
• Radiative energy loss in a finite dynamical QCD medium
• Anomalous Transport Processes in Anisotropically Expanding Quark-Gluon Plasmas
• Jet broadening in unstable non-Abelian plasmas
• Jet quenching and broadening: the transport coefficient $\hat{q}$ in an anisotropic plasma
• Measuring Quark-Gluon-Plasma Thermalization Time with Dileptons
• Measuring the isotropization time of quark-gluon plasma from direct photons at energies available at the BNL Relativistic Heavy Ion Collider (RHIC)
• Evolution of Anisotropy of Parton System from Relativistic Heavy-Ion Collisions
• Radiative energy loss in an anisotropic Quark-Gluon-Plasma
• Quenching of light hadrons at RHIC in a collisional energy loss scenario

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• Covariant formulation of gluon self-energy in presence of ellipsoidal anisotropy
• Jet-dilepton conversion from an anisotropic quark-gluon plasma
• Gluon dissociation of $J/\psi$ in anisotropic {\em Quark-Gluon-Plasma}
• Two Photon Correlation in Anisotropic Quark-gluon plasma (aQGP)