Displaced vertex signature of type-I seesaw model

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.