Lepton Number Violating Processes Mediated by Majorana Neutrinos at Hadron Colliders

Abstract

We study the Lepton number violating like-sign dilepton processes $h_1{h}_2\to l^{\pm }{l}^{\prime \pm }jjX$ and $h_1{h}_2\to l^{\pm }{l}^{\prime \pm }{W}^{\pm }X$, 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 $U_{\alpha N}$ with $\alpha ={\nu }_e,{\nu }_{\mu },{\nu }_{\tau }$. Special attention is paid to the constraints from neutrinoless double beta decay. We note that searches for like-sign $e^{\pm }{e}^{\pm }$ events at Tevatron and LHC may shed light on CP-violation in 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.

Comments: 18 pages,6 figures