Finite Temperature effects on baryon transport scattering in the early   Universe
  We have computed finite temperature corrections to the electron-hadron scattering cross sections. These are based upon the renormalized electron mass and the modified density of states due to the presence of a background thermal bath. It is found that the electron-hadron thermal transport scattering cross section can be much larger than the zero temperature one. In the case of electron-neutron transport scattering, we find \sigma_{ne}(T) / \sigma_{ne} (T=0) \simeq 5 at T \simeq 0.1 MeV. 
In-Saeng Suh and G. J. Mathews