Sensitivity prospects for lepton-trijet signals in the νSMEFT at the LHeC

Abstract

The observation of neutrino oscillations andmasses motivates the extension of the standard model withright-handed neutrinos, leading to heavy neutrino states possibly in the electroweak scale, which could be impacted bynew high-scale weakly coupled physics. A systematic toolfor studying these interactions is the neutrino-extended standard model effective field theory νSMEFT. In this work westudy the prospects of the future LHeC electron-proton collider to discover or constrain the νSMEFT interactions, performing the first dedicated and realistic analysis of the wellknown lepton-trijet signals, for both the lepton flavor violating p e− → μ− +3j (LFV) and the lepton number violatingp e− → μ+ + 3j (LNV) channels, for HNLs masses inthe electroweak scale range: 100 GeV ≤ mN ≤ 500 GeV.The obtained sensitivity prospects show that the LHeC with100 fb−1 luminosity could be able to probe the scenario of aheavy N and constrain the effective couplings to a region ofthe parameter space as tight as the bounds that are currentlyconsidered for the O(10) GeV scale masses, with effectivecouplings of O(10−1) for NP scale = 1 TeV.