1 ↔2 processes of a sterile neutrino around the electroweak scale in a thermal plasma

In this paper, we apply the Goldstone equivalence gauge to calculate the 1 ↔2 processes of a sterile neutrino in a thermal plasma below the standard model (SM) critical temperature T_c≈160 GeV . The sterile neutrino's mass is around the electroweak scale, 50 GeV ≤m_N≤200 GeV , and the acquired thermal averaged effective width Γ_¯tot does not depend on the gauge selection and is continuous around the crossover. We also apply our results to perform a preliminary calculation of leptogenesis.