Nuclear shadowing effects on prompt photons at RHIC and LHC

  • The transverse momentum distribution of prompt photons coming from the very early phase of ultrarelativistic heavy ion collisions for the RHIC and LHC energies is calculated by means of perturbative QCD. We calculate the single photon cross section (A + B -> gamma + X) by taking into account the partonic sub processes q + q -> gamma + g and q + g -> gamma + q as well as the Bremsstrahlung corrections to those processes. We choose a lower momentum cut-off k0 = 2 GeV separating the soft physics from perturbative QCD. We compare the results for those primary collisions with the photons produced in reactions of the thermalized secondary particles, which are calculated within scaling hydrodynamics. The QCD processes are taken in leading order. Nuclear shadowing corrections, which alter the involved nuclear structure functions are explicitly taken into account and compared to unshadowed results. Employing the GRV parton distribution parametrizations we find that at RHIC prompt QCD-photons dominate over the thermal radiation down to transverse momenta kT ≈ 2 GeV. At LHC, however, thermal radiation from the QGP dominates for photon transverse momenta kT ≤ 5 GeV, if nuclear shadowing effects on prompt photon production are taken into account.

Download full text files

Export metadata

Additional Services

Share in Twitter Search Google Scholar
Author:Nils HammonGND, Adrian Bogdan DumitruGND, Horst StöckerORCiDGND, Walter GreinerGND
Document Type:Preprint
Date of Publication (online):2005/12/15
Year of first Publication:1998
Publishing Institution:Universitätsbibliothek Johann Christian Senckenberg
Release Date:2005/12/15
Tag:Kollisionen schwerer Ionen; LHC; QGP; Quanten Chromodynamik; Quark-Gluon Plasma
LHC; QGP; Quanten Chromodynamic; heavy ion collisions; quark-gluon plasma
Institutes:Physik / Physik
Dewey Decimal Classification:5 Naturwissenschaften und Mathematik / 53 Physik / 530 Physik
Licence (German):License LogoDeutsches Urheberrecht