The Plasmon Damping Rate for T -> T_C
  The plasmon damping rate in scalar field theory is computed close to the critical temperature. It is shown that the divergent result obtained in perturbation theory is a consequence of neglecting the thermal renormalization of the coupling. Taking this effect into account, a vanishing damping rate is obtained, leading to the critical slowing down of the equilibration process. 
Massimo Pietroni