LHC signals of radiatively-induced neutrino masses and implications for the Zee-Babu model

TL;DR

This paper explores how LHC data can test radiatively-induced neutrino mass models, like Zee-Babu, by analyzing exotic decay signatures and providing detailed background estimations, potentially constraining or excluding large parameter regions.

Contribution

It demonstrates that current and future LHC analyses can effectively probe radiative neutrino mass models, especially the Zee-Babu model, through dedicated multi-region strategies and background estimations.

Findings

Current LHC data can test certain Zee-Babu model regions.

Most of the parameter space could be excluded at 95% CL with high luminosity.

Exotic decay signatures require specialized multi-region analyses.

Abstract

Contrary to the see-saw models, extended Higgs sectors leading to radiatively-induced neutrino masses do require the extra particles to be at the TeV scale. However, these new states have often exotic decays, to which experimental LHC searches performed so far, focused on scalars decaying into pairs of same-sign leptons, are not sensitive. In this paper we show that their experimental signatures can start to be tested with current LHC data if dedicated multi-region analyses correlating different observables are used. We also provide high-accuracy estimations of the complicated Standard Model backgrounds involved. For the case of the Zee-Babu model, we show that regions not yet constrained by neutrino data and low-energy experiments can be already probed, while most of the parameter space could be excluded at the 95 % C.L. in a high-luminosity phase of the LHC.