On Radiative Corrections to Lepton-Number-Violating Processes

Abstract We consider the minimal model of the seesaw mechanism by introducing two right-handed neutrinos, whose masses are comparable to the electroweak scale. This framework is attractive, since it is testable in terrestrial experiments. A critical consequence of this mechanism is the violation of lepton-number conservation due to the Majorana masses of both active neutrinos and heavy neutral leptons. In particular, we investigate the impact of the radiative corrections to Majorana masses of left-handed neutrinos on lepton-number-violating processes, such as neutrinoless double beta decay, $(Z, A) \rightarrow (Z+2,A) + 2 e^-$, and inverse neutrinoless double beta decay, $e^- e^- \rightarrow W^- W^-$. It is shown that the cross section of inverse neutrinoless double beta decay can increase by ${\cal O}(10)$% when the masses of heavy neutral leptons are ${\cal O}(1)$ TeV, which has significant implications for future experiments.