Abstract

We study the lepton number violating like-sign dilepton processes h1h2?l±l'±jjX and h1h2?l±l'± W±X, mediated by heavy GeV scale Majorana neutrinos. We focus on the resonantly enhanced contributions with a nearly on-mass-shell Majorana neutrino in the s channel. We study the constraints on like-sign dilepton production at the Tevatron and the LHC on the basis of the existing experimental limits on the masses of heavy neutrinos and their mixings UaN with a=?e, ?µ, ?t. Special attention is paid to the constraints from neutrinoless double beta decay. We note that searches for like-sign e±e± events at Tevatron and LHC may provide evidence of CP violation in the neutrino sector. We also discuss the conditions under which it is possible to extract individual constraints on the mixing matrix elements in a model independent way. © 2009 The American Physical Society.