Right-Handed Neutrinos at LHC and the Mechanism of Neutrino Mass Generation

TL;DR

This paper explores the potential to detect right-handed neutrinos at the LHC, examining the symmetries and mechanisms that could allow their mixing with active neutrinos and implications for neutrino mass generation.

Contribution

It analyzes the conditions and symmetries necessary for significant mixing of right-handed neutrinos with active neutrinos and discusses their detectability at colliders.

Findings

Significant mixing requires a cancellation at the level of 10^{-8}.

Symmetries leading to this cancellation imply conservation of total lepton number.

Collider observables can be correlated with neutrino mass features under certain assumptions.

Abstract

We consider the possibility to detect right-handed neutrinos, which are mostly singlets of the Standard Model gauge group, at future accelerators. Substantial mixing of these neutrinos with the active neutrinos requires a cancellation of different contributions to the light neutrino mass matrix at the level of 10^{-8}. We discuss possible symmetries behind this cancellation and argue that they always lead to conservation of total lepton number. Light neutrino masses can be generated by small perturbations violating these symmetries. In the most general case, LHC physics and the mechanism of neutrino mass generation are essentially decoupled; with additional assumptions, correlations can appear between collider observables and features of the neutrino mass matrix.