Thermal Relaxation Time in Chemically Non-equilibrated Quark- Gluon Plasma

Abstract

The definition of thermal relaxation time is extended to chemically non-equilibrated quark-gluon plasma and the chemical non-equilibrated thermal relaxation times for partons are calculated using the non-equilibrium Debye mass as the infrared regulator. The dependence of the thermal relaxation time on the fugacity is given and the influence of the chemical non-equilibration is discussed. We find that there are threshold fugacities ${\lambda }_g^{\ast }$ and ${\lambda }_q^{\ast }$ for gluons and quarks. For \lambda_g < \lambda_g^* (\lambda_q < \lambda_q^*), \tau_g^{NEQ}/\tau_g^{EQ} (\tau_q^{NEQ}/\tau_q^{EQ}) decreases strongly with increasing fugacity, while for ${\lambda }_g>{\lambda }_g^{\ast }({\lambda }_q>{\lambda }_q^{\ast }$), the ratios are almost 1. It is shown that there is also the two-stage equilibration in a chemically non-equilibrated plasma. We also discussed the effect of using the non-equilibrium Deby mass as the infrared cutoff.

Comments: 11 pages, 4 figures, Revtex, submitted to Phys. Rev. C