Soft electromagnetic radiations from an equilibrating quark-gluon plasma

Abstract

We evaluate the bremsstrahlung production of low mass dileptons and soft photons from equilibrating and transversely expanding quark gluon plasma which may be created in the wake of relativistic heavy ion collisions. We use initial conditions obtained from the self-screened parton cascade model. We consider a boost invariant longitudinal and cylindrically symmetric transverse expansion of the parton plasma and find that for low mass dileptons $(M<~0.3 \mathrm{GeV})$ and soft photons ${(p}_{T}<~0.5 \mathrm{GeV}),$ the bremsstrahlung contribution is rather large compared to annihilation process at both the Relativistic Heavy Ion Collider (RHIC) and Large Hadron Collider (LHC) energies. We also find an increase by a factor of 15--20 in the low mass dileptons and soft photons yield as one goes from RHIC to LHC energies.