Lepton Number Violating Processes Mediated by Majorana Neutrinos at Hadron Colliders

TL;DR

This paper investigates lepton number violating processes mediated by Majorana neutrinos at hadron colliders, analyzing experimental constraints and potential signals for CP violation and neutrino mixing parameters.

Contribution

It provides a detailed analysis of resonant Majorana neutrino contributions to like-sign dilepton production at colliders, including constraints from existing experiments and neutrinoless double beta decay.

Findings

Constraints on heavy neutrino masses and mixings from Tevatron and LHC data

Potential to observe CP-violation through like-sign dilepton events

Conditions for model-independent constraints on neutrino mixing elements

Abstract

We study the Lepton number violating like-sign dilepton processes $h_1 h_2 \to l^\pm l^{\prime \pm} jj X$ 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.