Charged-Particle Decay at Finite Temperature

Understand

Radiative corrections to the decay rate of charged fermions caused by the presence of a thermal bath of photons are calculated in the limit when temperatures are below the masses of all charged particles involved.

• The cancellation of finite-temperature infrared divergences in the decay rate is described in detail.
• Temperature-dependent radiative corrections to a two-body decay of a hypothetical charged fermion and to electroweak decays of a muon are given.
• We touch upon possible implications of these results for charged particles in the early Universe.