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Title: Transport rates and momentum isotropization of gluon matter in ultrarelativistic heavy-ion collisions

Abstract

To describe momentum isotropization of gluon matter produced in ultrarelativistic heavy-ion collisions, the transport rate of gluon drift and the transport collision rates of elastic (gg{r_reversible}gg) as well as inelastic (gg{r_reversible}ggg) perturbative quantum chromodynamics- (pQCD) scattering processes are introduced and calculated within the kinetic parton cascade Boltzmann approach of multiparton scatterings (BAMPS), which simulates the space-time evolution of partons. We define isotropization as the development of an anisotropic system as it reaches isotropy. The inverse of the introduced total transport rate gives the correct time scale of the momentum isotropization. The contributions of the various scattering processes to the momentum isotropization can be separated into the transport collision rates. In contrast to the transport cross section, the transport collision rate has an indirect but correctly implemented relationship with the collision-angle distribution. Based on the calculated transport collision rates from BAMPS for central Au+Au collisions at Relativistic Heavy Ion Collider energies, we show that pQCD gg{r_reversible}ggg bremsstrahlung processes isotropize the momentum five times more efficiently than elastic scatterings. The large efficiency of the bremsstrahlung stems mainly from its large momentum deflection. Due to kinematics, 2{yields}N (N>2) production processes allow more particles to become isotropic in momentum space and thus kinetically equilibratemore » more quickly than their back reactions or elastic scatterings. We also show that the relaxation time in the relaxation time approximation, which is often used, is strongly momentum dependent and thus cannot serve as a global quantity that describes kinetic equilibration.« less

Authors:
;  [1]
  1. Institut fuer Theoretische Physik, Johann Wolfgang Goethe-Universitaet Frankfurt, Max-von-Laue-Str. 1, D-60438 Frankfurt am Main (Germany)
Publication Date:
OSTI Identifier:
21061985
Resource Type:
Journal Article
Journal Name:
Physical Review. C, Nuclear Physics
Additional Journal Information:
Journal Volume: 76; Journal Issue: 2; Other Information: DOI: 10.1103/PhysRevC.76.024911; (c) 2007 The American Physical Society; Country of input: International Atomic Energy Agency (IAEA); Journal ID: ISSN 0556-2813
Country of Publication:
United States
Language:
English
Subject:
73 NUCLEAR PHYSICS AND RADIATION PHYSICS; 71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSICS; ANISOTROPY; APPROXIMATIONS; BREMSSTRAHLUNG; BROOKHAVEN RHIC; CROSS SECTIONS; DISTRIBUTION; ELASTIC SCATTERING; GLUON-GLUON INTERACTIONS; GLUONS; HEAVY ION REACTIONS; QUANTUM CHROMODYNAMICS; QUARK MATTER; QUARKS; RADIATION TRANSPORT; RELATIVISTIC RANGE; RELAXATION TIME; SPACE-TIME

Citation Formats

Zhe, Xu, and Greiner, Carsten. Transport rates and momentum isotropization of gluon matter in ultrarelativistic heavy-ion collisions. United States: N. p., 2007. Web. doi:10.1103/PHYSREVC.76.024911.
Zhe, Xu, & Greiner, Carsten. Transport rates and momentum isotropization of gluon matter in ultrarelativistic heavy-ion collisions. United States. https://doi.org/10.1103/PHYSREVC.76.024911
Zhe, Xu, and Greiner, Carsten. 2007. "Transport rates and momentum isotropization of gluon matter in ultrarelativistic heavy-ion collisions". United States. https://doi.org/10.1103/PHYSREVC.76.024911.
@article{osti_21061985,
title = {Transport rates and momentum isotropization of gluon matter in ultrarelativistic heavy-ion collisions},
author = {Zhe, Xu and Greiner, Carsten},
abstractNote = {To describe momentum isotropization of gluon matter produced in ultrarelativistic heavy-ion collisions, the transport rate of gluon drift and the transport collision rates of elastic (gg{r_reversible}gg) as well as inelastic (gg{r_reversible}ggg) perturbative quantum chromodynamics- (pQCD) scattering processes are introduced and calculated within the kinetic parton cascade Boltzmann approach of multiparton scatterings (BAMPS), which simulates the space-time evolution of partons. We define isotropization as the development of an anisotropic system as it reaches isotropy. The inverse of the introduced total transport rate gives the correct time scale of the momentum isotropization. The contributions of the various scattering processes to the momentum isotropization can be separated into the transport collision rates. In contrast to the transport cross section, the transport collision rate has an indirect but correctly implemented relationship with the collision-angle distribution. Based on the calculated transport collision rates from BAMPS for central Au+Au collisions at Relativistic Heavy Ion Collider energies, we show that pQCD gg{r_reversible}ggg bremsstrahlung processes isotropize the momentum five times more efficiently than elastic scatterings. The large efficiency of the bremsstrahlung stems mainly from its large momentum deflection. Due to kinematics, 2{yields}N (N>2) production processes allow more particles to become isotropic in momentum space and thus kinetically equilibrate more quickly than their back reactions or elastic scatterings. We also show that the relaxation time in the relaxation time approximation, which is often used, is strongly momentum dependent and thus cannot serve as a global quantity that describes kinetic equilibration.},
doi = {10.1103/PHYSREVC.76.024911},
url = {https://www.osti.gov/biblio/21061985}, journal = {Physical Review. C, Nuclear Physics},
issn = {0556-2813},
number = 2,
volume = 76,
place = {United States},
year = {Wed Aug 15 00:00:00 EDT 2007},
month = {Wed Aug 15 00:00:00 EDT 2007}
}