86 research outputs found
A new mechanism of neutrino mass generation in the NMSSM with broken lepton number
In the Minimal Supersymmetric Standard Model with bilinear R-parity
violation, only one neutrino eigenstate acquires a mass at tree level,
consequently experimental data on neutrinos cannot be accommodated at tree
level. We show that in the Next-to-Minimal extension, where a gauge singlet
superfield is added to primarily address the so-called -problem, it is
possible to generate two massive neutrino states at tree level. Hence, the
global three-flavour neutrino data can be reproduced at tree level, without
appealing to loop dynamics which is vulnerable to model-dependent
uncertainties. We give analytical expressions for the neutrino mass eigenvalues
and present examples of realistic parameter choices.Comment: 9 pages, 2 figures; further clarifications added, to appear in PL
Looking for the minimal inverse seesaw realisation
In this work we consider a simple extension of the Standard Model involving
additional fermionic singlets and assume an underlying inverse seesaw mechanism
(with one or more right-handed neutrinos and one or more sterile fermions) for
neutrino mass generation. Under the assumption that both sterile states and
right-handed neutrinos are present, our goal is to determine which is the
minimal inverse seesaw realisation that accounts for neutrino data while at the
same time complying with all experimental requirements (electroweak precision
tests and laboratory constraints). This study aims at identifying the minimal
inverse seesaw realisation for the 3-flavour and for the 3 +~more-mixing
schemes, the latter giving an explanation for the reactor anomalies and/or
providing a possible candidate for the dark matter of the Universe. Based on a
perturbative approach, our generic study shows that in the class of inverse
seesaw models giving rise to a 3-flavour flavour mixing scheme, only two mass
scales are relevant (the light neutrino mass scale, and the mass of the
right-handed neutrinos, ) while in the case of a 3 + 1-mixing scheme, an
additional mass scale ( ) is required. For each of the two
obtained inverse seesaw frameworks, we conduct a thorough numerical analysis,
providing predictions for the hierarchy of the light neutrino spectrum and for
the effective mass in neutrinoless double beta decay.Comment: 29 pages, 14 figures. In V2, one paragraph, one figure, 3 references
and few minor comments added. Title slightly change
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