Parton-medium cross section and average QGP viscosity in lead-lead collisions at LHC

Abstract

The recent experimental CMS and E-by-E ATLAS data on the elliptic anisotropy of particles in \PbPb collisions are used to extract parton medium cross-section and the quark-gluon plasma viscosity-to-entropy ratio within the incomplete equilibration medium model. Our method assumes extrapolation of the measured pseudorapidity spectrum of charged particles to low-$p_T$ range. Then the rapidity distribution of both charged and neutral hadrons is restored. The extracted value of the parton-medium cross section is found to be $\ds σ= (3.1 \pm 0.2) {\rm mb}$. It yields $\eta /s=0.17\pm 0.02$ for the ratio of shear viscosity to entropy density in QGP phase. The last result is in a good agreement with the estimates obtained by calculations within the viscous hydrodynamics.

12 pages, 1 figure. arXiv admin note: text overlap with arXiv:1204.1409 by other authors

References in corpus (18)

• Glauber Modeling in High Energy Nuclear Collisions
• 200 A GeV Au+Au collisions serve a nearly perfect quark-gluon liquid
• On the Strongly-Interacting Low-Viscosity Matter Created in Relativistic Nuclear Collisions
• Suppression of elliptic flow in a minimally viscous quark-gluon plasma
• Event-by-event gluon multiplicity, energy density and eccentricities at RHIC and LHC
• Hydrodynamic Models for Heavy Ion Collisions
• The centrality dependence of elliptic flow, the hydrodynamic limit, and the viscosity of hot QCD
• Eccentricity fluctuations from the Color Glass Condensate at RHIC and LHC
• Elliptic flow for phi mesons and (anti)deuterons in Au+Au collisions at sqrt(s_NN) = 200 GeV
• Elliptic flow in U+U collisions at sqrt{s_{NN}} = 200 GeV and in Pb+Pb collisions at sqrt{s_{NN}} = 2.76 TeV: Prediction from a hybrid approach
• Fluid Dynamics and Viscosity in Strongly Correlated Fluids
• Eccentricity distributions in nucleus-nucleus collisions
• Elliptic flow in transport theory and hydrodynamics
• Azimuthal Anisotropy Distributions in High-Energy Collisions
• Quark-Gluon Plasma at RHIC and the LHC: Perfect Fluid too Perfect?
• Elucidating the event-by-event flow fluctuations in heavy-ion collisions via the event shape selection technique
• Knudsen number, ideal hydrodynamic limit for elliptic flow and QGP viscosity in $\sqrt{s}$=62 and 200 GeV Cu+Cu/Au+Au collisions
• Hints of incomplete thermalization in RHIC data