Multiplicity, mean pT, pT-spectra and elliptic flow of identified particles in Pb+Pb collisions at LHC

Israel–Stewart's causal theory of dissipative hydrodynamics, with the ADS/CFT lower limit of shear viscosity to entropy ratio (η/s=0.08), give consistent description of a number of experimental observables in Au + Au collisions at RHIC (c.m. energy s=200 GeV) [A.K. Chaudhuri, arXiv: 0801.3180 [nucl-th]]. Assuming that in Pb + Pb collisions at LHC (c.m. energy s=5.5 TeV), except for the initial temperature, other parameters of the fluid remain unchanged, we have predicted for the centrality dependence of multiplicity, mean pT, pT-spectra, elliptic flow. The central temperature of the fluid is adjusted to Ti=421 MeV such that in a Pb + Pb collision, with participant number Npart=350, average charge particle multiplicity is ∼900 and is consistent with the experimental trend observed at lower energies. Compare to Au+Au collisions at RHIC, in Pb + Pb collisions at LHC, on the average, particle multiplicity increases by a factor of ∼1.6, the mean pT is increased by ∼10% only. The elliptic flow on the other hand decreases by ∼15%.