Transport coefficients of the quark-gluon plasma in ultrarelativistic   limit
  The calculation of the transport coefficients of the strong quark-gluon plasma (sQGP), i.e. sheer viscosity $\eta$, heat conductivity $\gk$ and bulk viscosity $\zeta$, in the first Chapman-Enskog approximation is presented. Their formulation in terms of two-fold integrals depending on the particle interaction, known as relativistic omega integrals, is derived and their evaluation in the ultrarelativistic limit is worked out assuming a cross section independent of the relative and total momentum of two colliding particles. We find a suppression of the bulk viscosity and a pronounced temperature dependence for the sheer viscosity and heat conductivity. However, at high temperatures, they scale with the third and second power of the temperature respectively as expected. Furthermore, we find that all results in this ultrarelativistic expansion are dominated by the leading order contribution. 
Stefano Mattiello
hep-ph nucl-th