Lepton number violation (LNV) is usually searched for by the LHC collaborations using the same-sign dilepton plus jet signature. In this paper, we discuss multilepton signals of LNV that can arise with experimentally interesting rates in certain loop models of neutrino mass generation. Interestingly, in such models, the observed smallness of the active neutrino masses, together with the high multiplicity of the final states, leads in large parts of the viable parameter space of such models to the prediction of long-lived charged particles, which leave highly ionizing tracks in the detectors. We focus on one particular one-loop neutrino mass model in this class and discuss its LHC phenomenology in some detail.

M. H. is supported by the Spanish Grant No. FPA2017-85216-P (AEI/FEDER, UE) and No. PROMETEO/2018/165 (Generalitat Valenciana). G. C. acknowledges supportfrom FONDECYT-Chile Grant No. 3190051. J. C. H. is supported by Chile FONDECYT Grant No. 1161463. G. C. and J. C. H. also acknowledge support from FONDECYT Grant No. 1201673. C. A. is supported by FONDECYTChile Grant No. 11180722 and Agencia Nacional de Investigación y Desarrollo-Chile Grant No.PIA/APOYOAFB 180002.