COMPTON-SCATTERING AT FINITE-TEMPERATURE

Compton scattering at finite temperature is studied with the real-time formalism of finite-temperature quantum held theory based on the clos ed-time path approach. It is found that, in the Born approximation con vention in zero-temperature quantum field theory, the thermal differen tial cross section differs from the zero-temperature one by a temperat ure-dependent factor. This factor, coming from the temperature-depende nt external propagators and having a great influence on the magnitude of the total cross section, is absent in previous works. As a result, the corrections can be surprisingly large for high temperatures realis tic in astrophysics.