Abstract
The linear seesaw mechanism provides a simple way to generate neutrino masses. In addition to Standard Model particles, it includes quasi-Dirac leptons as neutrino mass mediators, and a leptophilic scalar doublet seeding small neutrino masses. Here we review its associated physics, including restrictions from theory and phenomenology. The model yields potentially detectable μ → eγ rates as well as distinctive signatures in the production and decay of heavy neutrinos (Ni) and the charged Higgs boson (H±) arising from the second scalar doublet. We have found that production processes such as e+e− → NN, e−γ → NH− and e+e− → H+H− followed by the decay chain \( {H}^{\pm}\to {\ell}_i^{\pm }N \), \( N\to {\ell}_j^{\pm }{W}^{\mp } \) leads to striking lepton number violation signatures at high energies which may probe the Majorana nature of neutrinos.
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Acknowledgments
The work of A.B. is supported by Fundação para a Ciência e a Tecnologia (FCT, Portugal) through the PhD grant UI/BD/154391/2023 and through the projects CFTP-FCT Unit UIDB/00777/2020 and UIDP/00777/2020, CERN/FIS-PAR/0019/2021, which are partially funded through POCTI (FEDER), COMPETE, QREN and EU. The work of P.B. is supported by the CSIR JRF-NET fellowship. The work of S.M. is supported by KIAS Individual Grants (PG086001) at Korea Institute for Advanced Study. The work of RS is supported by the Government of India, SERB Startup Grant SRG/2020/002303. The work of J.V. is supported by the Spanish grants PID2020-113775GB-I00 (AEI/10.13039/501100011033) and Prometeo CIPROM/2021/054 (Generalitat Valenciana).
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Batra, A., Bharadwaj, P., Mandal, S. et al. Phenomenology of the simplest linear seesaw mechanism. J. High Energ. Phys. 2023, 221 (2023). https://doi.org/10.1007/JHEP07(2023)221
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DOI: https://doi.org/10.1007/JHEP07(2023)221