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

Abstract

We study the production of heavy neutrinos at the Large Hadron Collider through the dominant 𝑠-channel production mode as well as the vector boson fusion process. We consider the TeV scale minimal linear seesaw model containing two heavy singlets with the opposite lepton number. This model is fully reconstructible from oscillation data apart from an overall normalization constant which can be constrained from the metastability of the electroweak vacuum and bounds coming from lepton flavor violation searches. The Dirac nature of heavy neutrinos in this model implies suppression of the conventional same-sign-dilepton signal at the Large Hadron Collider. We analyze the collider signatures with the trilepton final state and missing transverse energy as well as vector boson fusion 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 lepton flavor violation and metastability bounds, the model can be explored only for a light to moderate mass range of heavy neutrinos. We also note that in case of a positive signal, flavor counting of the final trilepton channel can give information about the mass hierarchy of the light neutrinos.