Radiative corrections to the Dark Matter particles annihilation into massive leptons

We calculate the radiative corrections to the annihilation of the Dark Matter particles into leptons. Lepton masses are taken into account. For the Dark Matter particles we consider both Dirac and Majorana fermions. We sum up all the leading logarithmic contributions where it is possible. We investigate the mass dependence of the resulting cross sections and show that quantitatively the answer is very sensitive to the lepton mass due to the leading logarithm singularity.