Updated Bounds on the Minimal Left-Right Symmetric Model from LHC Dilepton Resonance Searches

TL;DR

This paper uses LHC dilepton data to set new lower bounds on the mass of the $Z_R$ boson in the Left-Right symmetric model, expanding the parameter space constraints beyond previous charged current searches.

Contribution

It provides updated mass bounds on the $Z_R$ gauge boson for various gauge couplings, highlighting regions where the right-handed neutrino exceeds the $W_R$ mass, which were previously unexplored.

Findings

Lower bounds of 4.9 TeV and 6.1 TeV on $Z_R$ mass for different gauge couplings.

Limits cover new parameter space where right-handed neutrino is heavier than $W_R$.

Constraints are derived from 13 TeV LHC dilepton data with 139 fb$^{-1}$ luminosity.

Abstract

The Left-Right model is a popular extension of the Standard Model that features three new neutral gauge bosons, $W^{\pm}_R$ and $Z_R$. Collider searches for a Left-Right symmetry are often concentrated on the charged right-handed current, but in this work, we take advantage of the dilepton data at the LHC with center-of-mass energy of 13 TeV and 139 fb$^{-1}$ of integrated luminosity to place lower mass bounds in the $Z_R$ mass based on the $p\,p \rightarrow Z_{R} \rightarrow \ell^{+} \, \ell^{-}$ process. We vary the $SU(2)_R$ gauge coupling from $g_{R}=0.4$ to $g_{R}=1.0$, and impose $M_{Z_R}>4.9$ TeV and $M_{Z_{R}}>6.1$ TeV, respectively. Lastly, we put our findings into perspective with $W_R$ searches at the LHC and show that our limits cover an unexplored region of parameter space, where the right-handed neutrino is heavier than the $W_R$ boson.