Hunting for heavy majorana neutrinos with lepton number violating signatures at LHC

Abstract

The neutrinophilic two-Higgs-doublet model (ν2HDM) provides a natural way to generate tiny neutrino mass from interactions with the new doublet scalar Φ_ν (H^±, H, A) and singlet neutrinos N_R of TeV scale. In this paper, we perform detailed simulations for the lepton number violating (LNV) signatures at LHC arising from cascade decays of the new scalars and neutrinos with the mass order $m_{N_R}<m{\Phi }_{\nu }$^. Under constraints from lepton flavor violating processes and direct collider searches, their decay properties are explored and lead to three types of LNV signatures: [inline-graphic not available: see fulltext] , and 3ℓ^±ℓ^∓4j. We find that the same-sign trilepton signature [inline-graphic not available: see fulltext] is quite unique and is the most promising discovery channel at the high-luminosity LHC. Our analysis also yields the 95% C.L. exclusion limits in the plane of the Φ_ν and N_R masses at 13 (14) TeV LHC with an integrated luminosity of 100 (3000) fb⁻¹.