Probing Heavy-Light Neutrino Mixing in Left-Right Seesaw Models at the LHC

TL;DR

This paper investigates how heavy-light neutrino mixing in TeV-scale left-right symmetric seesaw models affects collider signals at the LHC, proposing methods to distinguish these effects and showing current data already constrains the models.

Contribution

It introduces a new dominant contribution to collider signals from heavy-light neutrino mixing and proposes a way to distinguish it from other contributions.

Findings

Existing LHC data constrains heavy-light neutrino mixing more than standard models.

The proposed analysis can improve constraints with more data.

New dominant contributions to collider signals are identified in specific models.

Abstract

We show that in TeV-scale left-right (L-R) symmetric seesaw models, there are new dominant contributions to the collider signals of heavy Majorana neutrinos arising from the heavy-light neutrino mixing, which directly probe the seesaw matrix in a certain class of models. We propose a way to distinguish this contribution from the widely discussed one that only probes the Majorana nature of the heavy right-handed neutrinos, by analyzing some simple kinematical variables. We find that in this class of L-R seesaw models the existing LHC data already yield slightly stronger constraints on the heavy-light neutrino mixing than those derived for standard seesaw models, and the improvement will be significant as more data are collected.