Measuring CP violation in rare W decays at the LHC*

Abstract

Abstract Heavy Majorana neutrinos beyond the standard model can simultaneously explain the origin of tiny neutrino masses and matter-antimatter asymmetry in our Universe. The existence of heavy Majorana neutrinos will also lead to lepton number violation and confirm the possibility of rare lepton-number-violating W decays. With contributions from two different Majorana neutrinos, nonzero CP asymmetry may be generated from the rate difference between W decay and its CP-conjugate process. The aim of this study is to investigate the prospects of measuring CP violation in rare W decays via Majorana neutrinos at the LHC. Our calculations show that the induced CP asymmetry is independent of the Majorana neutrino mass for . Such a CP asymmetry, if observed, would in turn provide unambiguous evidence of new physics beyond the standard model.