Chemical equilibration in viscous quark-gluon plasma and electromagnetic signals

We investigate the chemical equilibration of the parton distributions in collisions of two heavy nuclei, assuming the partonic fluid to be ideal as well as viscous. The initial conditions are taken from HIJING calculations for Au+Au collisions at RHIC and LHC energies. It was seen that when the viscous drag is taken into account in the fluid flow, the life time of the plasma is increased by nearly a factor of 2. The temperature as well as fugacities evolve slowly than their ideal counterpart. The photon and lepton pair production was also investigated. There is a two fold increase in the photon and lepton pair numbers with viscosity on. The increase in the large $p_T$ photons and the large invariant mass lepton pairs are due to slower rate of temperature evolution.