Thermalization of Quark Matter Produced at the Highest Energy of a Relativistic Heavy-Ion Collider

Thermalization of quark matter is studied via a transport equation, which includes triple-quark elastic scattering amplitudes calculated in perturbative QCD. The triple-quark scatterings are demonstrated to be important for an anisotropic initial quark distribution produced in central Au-Au collisions at √SNN=200GeV. By examining momentum isotropy to which the transport equation leads, we can determine a thermalization time of 2.2fm/c for quark matter itself to thermalize by the two-quark and the triple-quark elastic scatterings. Meanwhile, an initial thermal quark distribution function is obtained.