Seminar in Hadronic Physics

Viscous hydrodynamic radial and elliptic flow from RHIC to LHC

Chun Shen

Ohio State University

Using viscous hydrodynamics and a state-of-the-art equation of state, s95p-PCE, we explore the dependence of the final observed hadron spectra and elliptic flow on the input parameters, in particular shear viscosity. Based on these experiences, we present an excellent fit for the spectra and elliptic flow of all charged hadrons as well as identified pions and protons from Au+Au collisions of all centralities measured at the Relativistic Heavy Ion Collider (RHIC). Taking this global fit as starting point, we extrapolate to higher Large Hadron Collider (LHC) energies and predict the analogous observables for Pb+Pb collisions at √s=2.76 and 5.5 A TeV, assuming the same constant specific shear viscosity η/s and thermalization time at both collision energies. Comparison with recent ALICE measurements of the elliptic flow of charged hadrons shows that the model slightly overpredicts the data. This indicates some possible temperature dependence of (η/s)(T), and I will show some results when I explain this possibility. Future experiments will further test the model and shed additional light on possible variations of the quark-gluon transport coefficients between RHIC and LHC energies.