Photons from anisotropic quark-gluon plasma

Abstract

We calculate medium photons due to Compton and annihilation processes in an anisotropic media. The effects of time-dependent momentum-space anisotropy of quark-gluon plasma (QGP) on the medium photon production are discussed. Such an anisotropy can result from the initial rapid longitudinal expansion of the matter, created in relativistic heavy ion collisions. A phenomenological model for the time-dependence of the parton hard momentum scale, p hard (τ ), and anisotropy parameter, ξ (τ ), has been used to describe the plasma space-time evolution. We find significant dependency of photon yield on the isotropization time (τ iso ). It is shown that the introduction of early time momentum-space anisotropy can enhance the photon production by a factor of 10(1.5) (in the central rapidity region) for the free streaming (collisionally-broadened) interpolating model if we assume fixed initial condition. On the other hand, enforcing the fixed final multiplicity significantly reduces the enhancement of medium photon production.

Measuring the isotropization time of quark-gluon plasma from direct photons at energies available at the BNL Relativistic Heavy Ion Collider (RHIC)

“…[21] that for fixed initial conditions, the introduction of a preequilibrium momentumspace anisotropy enhances high-energy dileptons by an order of magnitude. In the case of photon transverse momentum distribution similar results have been reported for various evolution scenarios [22]. The model in Ref.…”

Wake potential in collisional anisotropic quark-gluon plasma

“…The effect of anisotropy on the photon and dilepton yield has been investigated rigorously in Refs. [31][32][33][34][35].…”

Gluon dissociation ofJ/ψin anisotropic quark-gluon plasma

“…Effects of anisotropy on photon and dilepton yields have been investigated rigorously in Ref. [10,11,12,13,14]. The effect of initial state momentum anisotropy on the radiative energy loss has been demonstrated in Ref.…”