Related papers: Neutrino Masses from Fine Tuning
Recently, an extension of the standard model based on ideas of Lee and Wick has been discussed. This theory is free of quadratic divergences and hence has a Higgs mass that is stable against radiative corrections. Here, we address the…
The seesaw mechanism of neutrino mass generation is analysed under the following assumptions: (1) minimal seesaw with no Higgs triplets, (2) hierarchical Dirac masses of neutrinos, (3) large lepton mixing primarily or solely due to the…
We present a model of neutrino masses within the framework of the EW-$\nu_R$ model in which the experimentally desired form of the PMNS matrix is obtained by applying an $A_4$ symmetry to the \emph{Higgs singlet sector} responsible for the…
A novel scenario is presented within the Type-I seesaw mechanism in which no other beyond Standard Model fields except three heavy right handed neutrinos, have been considered. Light neutrino masses around sub eV scale, could be possible at…
We consider various possibilities for generating neutrino masses in supersymmetric models with an additional U(1)' gauge symmetry. One class of models involves two extra U(1)' x U(1)'' gauge symmetries, with U(1)'' breaking at an…
Assuming the seesaw mechanism for hierarchical neutrino masses, we calculate the heavy neutrino masses under the hypotheses that the mixing in the Dirac leptonic sector is similar to the quark mixing ($V_D \sim V_{CKM}$) and that $M_{\nu}…
The relic neutrinos are expected to acquire a bulk relative velocity with respect to the dark matter at low redshifts, and neutrino wakes are expected to develop downstream of the dark matter halos. We propose a method of measuring the…
We propose a model in which small neutrino masses are generated via Yukawa coupling to a self-interacting ultralight dark matter (ULDM) field, treated as a pseudo-Nambu-Goldstone boson associated with a heavy Higgs-like field. ULDM has a…
It is found that the seesaw mechanism not only explain the smallness of neutrino masses but also account for the large mixing angles simultaneously, even if the unification of the neutrino Dirac mass matrix with that of up-type quark sector…
General classes of mechanisms for generating small neutrino masses are surveyed from a top-down (superstring) perspective. In particular, string constructions have motivated various possibilities involving higher-dimensional operators,…
A Higgs sextet is introduced in order to generate Dirac and Majorana neutrino masses in the 331 model with right-handed neutrinos. As will be seen, the present sextet introduction leads to a rich neutrino mass structure. The smallness of…
The seesaw mechanism provides a simple explanation for the lightness of the known neutrinos. Under the standard assumption of a weak scale Dirac mass and a heavy sterile Majorana scale the neutrino mass is naturally suppressed below the…
In the inverse see-saw model the effective neutrino Yukawa couplings can be sizable due to a large mixing angle between the light $(\nu)$and heavy neutrinos $(N)$. When the right handed neutrino $(N)$ can be lighter than the Standard Model…
If the Standard Model particle content is extended by gauge singlet fermions (right-handed neutrinos), active neutrinos generically acquire (Majorana) masses, in agreement with our current understanding of the lepton sector. If the…
The usual see-saw mechanism for the generation of light neutrino masses is based on the assumption that all of the flavours of right-handed (more properly, sterile) neutrinos are heavy. If the sterile Majorana mass matrix is singular, one…
New models have recently been proposed in which a second Higgs doublet couples only to the lepton doublets and right-handed neutrinos, yielding Dirac neutrino masses. The vacuum value of this second "nu-Higgs" doublet is made very small by…
A neutrino mass model is suggested within an $SU(4)\times U(1)$ -- electroweak theory. The smallness of neutrino masses can be guaranteed by a seesaw mechanism realized through Yukawa couplings to a scalar $SU(4)$-decuplet. In this scheme…
We consider a neutrinophilic Higgs scenario where the Standard Model is extended by one additional Higgs doublet and three generations of singlet right-handed Majorana neutrinos. Light neutrino masses are generated through mixing with the…
A simple and economical extension of the minimal standard electroweak gauge model (without right-handed neutrinos) by the addition of two heavy Higgs scalar triplets would have two significant advantages. \underline {Naturally} small…
An alternative to the conventional see-saw mechanism is proposed to explain the origin of small neutrino masses in supersymmetric theories. The masses and couplings of the right-handed neutrino field are suppressed by supersymmetry…