%0 Unpublished work
%T Quark production, Bose-Einstein condensates and thermalization of the quark-gluon plasma
%+ Service de Physique ThÃ©orique (SPhT)
%+ Ontario Cancer Institute
%+ Institut de Physique ThÃ©orique - UMR CNRS 3681 (IPHT)
%+ Horiba Scientific [New Jersey]
%A Blaizot, Jean-Paul
%A Wu, Bin
%A Yan, Li
%Z 31 pages, 25 figures
%8 2014-02-20
%D 2014
%Z 1402.5049
%Z Physics [physics]/High Energy Physics - Phenomenology [hep-ph]
%Z Physics [physics]/Nuclear Theory [nucl-th]Preprints, Working Papers, ...
%X In this paper, we study the thermalization of gluons and N_f flavors of massless quarks and antiquarks in a spatially homogeneous system. First, two coupled transport equations for gluons and quarks (and antiquarks) are derived within the diffusion approximation of the Boltzmann equation, with only 2<-> 2 processes included in the collision term. Then, these transport equations are solved numerically in order to study the thermalization of the quark-gluon plasma. At initial time, we assume that no quarks or antiquarks are present and we choose the gluon distribution in the form f = f_0 theta (1-p/Q_s) with Q_s the saturation momentum and f_0 a constant. The subsequent evolution of systems may, or may not, lead to the formation of a (transient) Bose condensate, depending on the value of f_0. In fact, we observe, depending on the value of f_0, three different patterns: (a) thermalization without gluon Bose-Einstein condensate (BEC) for f_0 < f_{0t}, (b) thermalization with transient BEC for f_{0t} < f_0 < f_{0c}, and (c) thermalization with BEC for f_{0c} < f_0. The values of f_{0t} and f_{0c} depend on N_f. When f_0> 1 > f_{0c}, the onset of BEC occurs at a finite time t_c ~ 1/((alpha_s f_0)^2 Q_s). We also find that quark production slows down the thermalization process: the equilibration time for N_f = 3 is typically about 5 to 6 times longer than that for N_f = 0 at the same Q_s.
%G English
%L cea-00979513
%U https://cea.hal.science/cea-00979513
%~ CEA
%~ CNRS
%~ DSM-IPHT
%~ CEA-DRF
%~ GS-MATHEMATIQUES
%~ GS-PHYSIQUE