Searching for light new physics at the LHC via lepton-number violation

TL;DR

This paper investigates the potential for detecting light new physics involving right-handed W bosons and Majorana neutrinos at the LHC, focusing on lepton-number-violating signals with three same-sign leptons.

Contribution

It introduces a simplified model with a right-handed W boson coupled to the third generation and a light Majorana neutrino, analyzing its collider signatures and detection prospects.

Findings

Right-handed W boson can be as light as 300 GeV.

Lepton-number-violating signals with three same-sign leptons are promising detection channels.

Existing LHC and Tevatron searches still allow for this new physics to exist.

Abstract

We study the collider phenomenology of a simplified model containing a right-handed $W$ in which the $W_R$ couples predominantly to the third generation in the quark sector. The model also includes a light Majorana neutrino, with $M_1\sim {\cal O}(100)$ GeV, giving rise to lepton-number-violating signatures that are visible at the LHC. Taking into account all the searches from the LHC and Tevatron, we find that this $W_R$ can still be as light as $M_R \sim 300$ GeV. We show that this type of new physics, and others like it, can be detected at the LHC using final states with three same-sign same-flavour leptons.