https://doi.org/10.1140/epjc/s10052-024-13149-y
Regular Article - Theoretical Physics
Neutrino masses from new seesaw models: low-scale variants and phenomenological implications
1
Dipartimento di Matematica e Fisica, Universitá di Roma Tre, Via della Vasca Navale 84, 00146, Rome, Italy
2
INFN Sezione di Roma Tre, Via della Vasca Navale 84, 00146, Rome, Italy
3
Departament de Física Teòrica, Universitat de València, 46100, Burjassot, Spain
4
Instituto de Física Corpuscular (CSIC-Universitat de València), Parc Científic UV, C/Catedrático José Beltrán, 2, 46980, Paterna, Spain
Received:
21
May
2024
Accepted:
24
July
2024
Published online:
12
August
2024
With just the Standard Model Higgs doublet, there are only three types of seesaw models that generate light Majorana neutrino masses at tree level after electroweak spontaneous symmetry breaking. However, if there exist additional TeV scalars acquiring vacuum expectation values, coupled with heavier fermionic multiplets, several new seesaw models become possible. These new seesaws are the primary focus of this study and correspond to the tree-level ultraviolet completions of the effective operators studied in a companion publication. We are interested in the genuine cases, in which the standard seesaw contributions are absent. In addition to the tree-level generation of neutrino masses, we also consider the one-loop contributions. Furthermore, we construct low-energy versions that exhibit a very rich phenomenology. Specifically, we scrutinise the generation of dimension-6 operators and explore their implications, including non-unitarity of the leptonic mixing matrix, non-universal 
boson interactions, and lepton flavor violation. Finally, we provide (Generalised) Scotogenic-like variants that incorporate viable dark matter candidates.
© The Author(s) 2024
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Funded by SCOAP3.
