Sensitivity prospects for lepton-trijet signals in the $$\nu $$SMEFT at the LHeC

Abstract

AbstractThe observation of neutrino oscillations and masses motivates the extension of the standard model with right-handed neutrinos, leading to heavy neutrino states possibly in the electroweak scale, which could be impacted by new high-scale weakly coupled physics. A systematic tool for studying these interactions is the neutrino-extended standard model effective field theory $$\nu $$ ν SMEFT. In this work we study the prospects of the future LHeC electron-proton collider to discover or constrain the $$\nu $$ ν SMEFT interactions, performing the first dedicated and realistic analysis of the well known lepton-trijet signals, for both the lepton flavor violating $$p ~ e^{-} \rightarrow \mu ^{-} + 3 \textrm{j}$$ p e - → μ - + 3 j (LFV) and the lepton number violating $$p ~ e^{-} \rightarrow \mu ^{+} + 3 \textrm{j}$$ p e - → μ + + 3 j (LNV) channels, for HNLs masses in the electroweak scale range: $$100 ~{\textrm{GeV}} \le m_N \le 500 ~{\textrm{GeV}}$$ 100 GeV ≤ m N ≤ 500 GeV . The obtained sensitivity prospects show that the LHeC with $$100 ~{\textrm{fb}}^{-1}$$ 100 fb - 1 luminosity could be able to probe the scenario of a heavy N and constrain the effective couplings to a region of the parameter space as tight as the bounds that are currently considered for the $$\mathcal {O}(10)$$ O ( 10 ) GeV scale masses, with effective couplings of $$\mathcal {O}(10^{-1})$$ O ( 10 - 1 ) for NP scale $$\Lambda =1 \,{\textrm{TeV}}$$ Λ = 1 TeV .