Compton scattering at finite temperature is studied with the real-time formalism of finite-temperature quantum field theory based on the closed-time path approach. It is found that, in the Born approximation convention in zero-temperature quantum field theory, the thermal differential cross section differs from the zero-temperature one by a temperature-dependent factor. This factor, coming from the temperature-dependent 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 realistic in astrophysics.

• Received 5 August 1994

DOI:https://doi.org/10.1103/PhysRevD.52.6116