Testing left-right symmetry with an inverse seesaw mechanism at the LHC

TL;DR

This paper explores a new process involving right-handed neutrinos in left-right symmetric models with inverse seesaw at the HL-LHC, proposing a novel way to probe neutrino mass mechanisms through distinctive collider signatures.

Contribution

It introduces a previously unstudied collider process for testing the inverse seesaw mechanism in left-right models at the HL-LHC, focusing on a unique decay channel involving a boosted W-like jet.

Findings

Potential to discover a 6 TeV W' boson at HL-LHC

Identification of a distinctive collider signature with same-flavor leptons and a fatjet

Demonstrates the feasibility of probing inverse seesaw mechanisms at high energies

Abstract

In the left-right symmetric models, a heavy charged gauge boson $W'$ can decay to a lepton and a right-handed neutrino (RHN). If the neutrino masses are generated through the standard type-I seesaw mechanism, the Yukawa couplings controlling two-body decays of the RHN become very small. As a result, the RHN decays to another lepton and a pair of jets via an off-shell $W'$. This is the basis of the Keung-Senjanovi\'{c} (KS) process, which was originally proposed as a probe of lepton number violation at the LHC. However, if a different mechanism like the inverse seesaw generates the neutrino masses, a TeV-scale RHN can have large Yukawa couplings and hence dominantly decay to a lepton and a $W$ boson, leading to a kinematically different process from the KS one. We investigate the prospect of this unexplored process as a probe of the inverse seesaw mechanism in the left-right symmetric models at the High Luminosity LHC (HL-LHC). Our signal arises from the Drell-Yan production of a $W'$ and leads to two high-$p_T$ same-flavour-opposite-sign leptons and a boosted $W$-like fatjet in the final state. We find that a sequential $W'$ with mass up to $\sim 6$~TeV along with a TeV-scale RHN can be discovered at the HL-LHC.