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
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.
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Metadaten
Author:Nils Hammon, Adrian Dumitru, Horst Stöcker, Walter Greiner
URN:urn:nbn:de:hebis:30-23246
Document Type:Preprint
Language:English
Date of Publication (online):2005/12/15
Year of first Publication:1998
Publishing Institution:Univ.-Bibliothek Frankfurt am Main
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
Source:Phys.Rev.C57:3292-3298,1998, http://arxiv.org/abs/hep-ph/9801292
HeBIS PPN:185326935
Institutes:Physik
Dewey Decimal Classification:530 Physik
Sammlungen:Universitätspublikationen
Licence (German):License Logo Veröffentlichungsvertrag für Publikationen

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