The Seesaw with Many Right-Handed Neutrinos

dc.creatorEllis, John
dc.creatorLebedev, Oleg
dc.date2007-07-23
dc.date2007-08-22
dc.date.accessioned2026-07-07T11:18:03Z
dc.date.available2026-07-07T11:18:03Z
dc.descriptionThere are no upper limits on the possible number of massive, singlet (right--handed) neutrinos that may participate in the seesaw mechanism, and some string constructions motivate seesaw models with up to O(100) right--handed neutrinos. In this case, the seesaw mass scale can be significantly higher than that in the traditional scheme with just 3 right--handed neutrinos. We consider the possible phenomenological implications of such models, in particular, for lepton-flavour violation and electric dipole moments. Since the neutrino masses depend on the Majorana mass scale linearly, while supersymmetric loop corrections depend on it logarithmically, the magnitude of lepton-flavour- and CP-violating transitions may increase with the multiplicity of the right--handed neutrinos and may be enhanced by orders of magnitude. We also point out that, in the context of leptogensis, the bounds on the reheating temperature and the lightest neutrino mass get relaxed compared to those in the case of 3 right--handed neutrinos.
dc.description14 pages; refs. added, published version
dc.identifierhttps://arxiv.org/abs/0707.3419
dc.identifierhttp://arxiv.org/abs/0707.3419
dc.identifierPhys.Lett.B653:411-418,2007
dc.identifierdoi:10.1016/j.physletb.2007.08.031
dc.identifier.urihttp://salesiana.dossiersoluciones.com/handle/123456789/193214
dc.subjectHigh Energy Physics - Phenomenology
dc.titleThe Seesaw with Many Right-Handed Neutrinos
dc.typetext

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