Looking for hints of a reconstructible seesaw model at the Large Hadron Collider

TL;DR

This paper investigates the potential to detect a minimal linear seesaw model with heavy neutrinos at the LHC, focusing on collider signatures and the impact of existing constraints on the model's testability.

Contribution

It provides a detailed analysis of collider signatures for a reconstructible seesaw model, considering constraints from lepton flavor violation and vacuum stability.

Findings

Model can be explored only for light to moderate heavy neutrino masses.

Tri-lepton signals can reveal neutrino mass hierarchy if detected.

Constraints limit the parameter space for heavy neutrino detection.

Abstract

We study the production of heavy neutrinos at the Large Hadron Collider (LHC) through the dominant s-channel production mode as well as the vector boson fusion (VBF) process. We consider the TeV scale minimal linear seesaw model containing two heavy singlets with opposite lepton number. This model is fully reconstructible from oscillation data apart from an overall normalization constant which can be constrained from meta-stability of the electroweak vacuum and bounds coming from lepton flavor violation (LFV) searches. Dirac nature of heavy neutrinos in this model implies suppression of the conventional same-sign-dilepton signal at the LHC. We analyze the collider signatures with tri-lepton final state and missing transverse energy as well as VBF type signals which are characterized by two additional forward tagged jets. Our investigation reveals that due to stringent constraints on light-heavy mixing coming from LFV and meta-stability bounds, the model can be explored only for light to moderate mass range of heavy neutrinos. We also note that in case of a positive signal, flavor counting of the final tri-lepton channel can give information about the mass hierarchy of the light neutrinos.