New Weinberg operator for neutrino mass and its seesaw origin

Abstract

We consider a new Weinberg operator for neutrino mass of the form H_uH˜ _dL_iL_j involving two different Higgs doublets H_u, H_d with opposite hypercharge, where H˜ s_d is the charge conjugated doublet. It may arise from a model where the two Higgs doublets carry the same charge under a U(1)^′ gauge group which forbids the usual Weinberg operator but allows the mixed one. The new Weinberg operator may be generated via two right-handed neutrinos oppositely charged under the U(1)^′, which may be identified as components of a fourth vector-like family in a complete model. Such a version of the type I seesaw model, which we refer to as type Ib to distinguish it from the usual type Ia seesaw mechanism which yields the usual Weinberg operator, allows the possibility of having potentially large violations of unitarity of the leptonic mixing matrix whose bounds we explore. We also consider the relaxation of the unitarity bounds due to the further addition of a single right-handed neutrino, neutral under U(1)^′, yielding a usual type Ia seesaw contribution.

More information

Identifiers

Catalogue record

Export record

ASCII CitationAtomBibTeXData Cite XMLDublin CoreDublin CoreEP3 XMLEndNoteHTML CitationHTML CitationHTML ListJSONMETSMODSMPEG-21 DIDLOpenURL ContextObjectOpenURL ContextObject in SpanRDF+N-TriplesRDF+N3RDF+XMLRIOXX2 XMLReferReference ManagerSimple Metadata

Altmetrics