In this paper we examine the pair production through the Breit-Wheeler
process γ γ→e+e− in a thermal background. We compute the
thermal contribution to the Breit-Wheeler differential cross section within the
thermofield dynamics formalism. We evaluate in details the cross section for
this process, which possess a surprisingly simple expression valid for any
temperature β, from which we discuss some physically relevant aspects. We
also consider the high temperature regime of the cross section in order to have
a better understanding about its thermal behavior.Comment: 13 pages, accepted for publication in EPJ