title: Thermalization of gluons with Bose-Einstein condensation.
abstract: We study the thermalization of gluons far from thermal equilibrium in relativistic kinetic theory. The initial distribution of gluons is assumed to resemble that in the early stage of ultrarelativistic heavy ion collisions. Only elastic scatterings in static, nonexpanding gluonic matter are considered. At first we show that the occurrence of condensation in the limit of vanishing particle mass requires a general constraint for the scattering matrix element. Then the thermalization of gluons with Bose-Einstein condensation is demonstrated in a transport calculation. We see a continuously increasing overpopulation of low energy gluons, followed by a decrease to the equilibrium distribution, when the condensation occurs. The times of the completion of the gluon condensation and of the entropy production are calculated. These times scale inversely with the energy density.
authors.affiliation: Department of Physics, Tsinghua University and Collaborative Innovation Center of Quantum Matter, Beijing 100084, China.
authors.forename: Zhe
authors.initials: Z
authors.lastname: Xu
authors.affiliation: Department of Physics, Tsinghua University and Collaborative Innovation Center of Quantum Matter, Beijing 100084, China.|Institut für Theoretische Physik, Johann Wolfgang Goethe-Universität Frankfurt, Max-von-Laue-Strasse 1, 60438 Frankfurt am Main, Germany.
authors.forename: Kai
authors.initials: K
authors.lastname: Zhou
authors.affiliation: Department of Physics, Tsinghua University and Collaborative Innovation Center of Quantum Matter, Beijing 100084, China.
authors.forename: Pengfei
authors.initials: P
authors.lastname: Zhuang
authors.affiliation: Institut für Theoretische Physik, Johann Wolfgang Goethe-Universität Frankfurt, Max-von-Laue-Strasse 1, 60438 Frankfurt am Main, Germany.
authors.forename: Carsten
authors.initials: C
authors.lastname: Greiner