Displaced vertex signature of type-I seesaw

TL;DR

This paper explores the potential to detect long-lived right-handed neutrinos via displaced vertices at future colliders within a minimal gauged B-L model, linking collider signatures with neutrino mass and neutrinoless double beta decay.

Contribution

It demonstrates that right-handed neutrinos can produce observable displaced vertices at next-generation colliders, with their lifetime linked to the lightest neutrino mass.

Findings

RHNs are long-lived and produce displaced vertices detectable at future colliders.

The lifetime of RHNs correlates with the lightest neutrino mass.

Displaced vertex searches complement neutrinoless double beta decay experiments.

Abstract

A certain class of new physics models includes long-lived particles which are singlet under the Standard Model (SM) gauge group.A displaced vertex is a spectacular signature to probe such particles productions at the high energy colliders, with a negligible SM background. In the context of the minimal gauged $B-L$ extended SM, we consider a pair creation of Majorana right-handed neutrinos (RHNs) at the high energy colliders through the production of the SM and the $B-L$ Higgs bosons and their subsequent decays into RHNs. With parameters reproducing the neutrino oscillation data, we show that the RHNs are long-lived and their displaced vertex signature can be observed at the next generation displaced vertex search experiments, such as the HL-LHC, the MATHUSLA, the LHeC, and the FCC-eh.We find that the lifetime of the RHNs is controlled by the lightest light neutrino mass, which leads to a correlation between the displaced vertex search and the search limit of the future neutrinoless double beta-decay experiments.