Can LHC Test the See-Saw Mechanism?

TL;DR

This paper explores the potential for future colliders to detect right-handed neutrinos in the see-saw mechanism, analyzing the symmetries involved and the implications for neutrino mass generation and collider physics.

Contribution

It identifies the symmetries necessary for the cancellation in the see-saw mechanism and examines their impact on collider observables and neutrino properties.

Findings

Lepton number conservation is essential for the cancellation.

Small symmetry-breaking perturbations generate light neutrino masses.

Collider signals are generally decoupled from neutrino mass mechanisms.

Abstract

We discuss the prospects for detecting right-handed neutrinos which are introduced in the see-saw mechanism at future colliders. This requires a very accurate cancellation between contributions from different right-handed neutrinos to the light neutrino mass matrix. We search for possible symmetries behind this cancellation and find that they have to include lepton number conservation. Light neutrino masses can be generated as a result of small symmetry-breaking perturbations. The impact of these perturbations on LHC physics is negligible, so that the mechanism of neutrino mass generation and LHC physics are decoupled in general. In constrained cases, accelerator observables and neutrino masses and mixings can be correlated.