Related papers: The LMA solar solution and fermion universality
We discuss the possibility of enforcing a massless Majorana neutrino in the direct and semi-direct approaches to lepton mixing, in which the PMNS matrix is partly predicted by subgroups of a discrete family symmetry, extending previous…
We perform global analysis of the solar neutrino data including the day and night spectra of events at SNO. In the context of two active neutrino mixing, the best fit of the data is provided by the LMA MSW solution with Delta m^2 = 6.15…
We propose two versions of radiative linear seesaw models, where electrically charged scalars and vector-like leptons generate the Dirac neutrino mass submatrix at one and two loop levels. In these models, the SM charged lepton masses are…
The comparison of the CKM mixing angles with the leptonic mixings implied by the recent atmospheric and solar neutrino data exhibits an interesting complementarity. This pattern can be understood in the context of the SU(5) grand…
Deviations from expectations have been claimed for solar, atmospheric and high energy prompt neutrinos from charm decay. This information, supplemented only by the existing very good upper limits for oscillations of the $\nu_{\mu}$ at…
We demonstrate that an $SU(2)_L\times U(1)_Y$ model with the same particle content as Standard Model(SM) and discrete reflection symmetry between second and third generation of leptons give rise to charged lepton and neutrino mass matrices…
A non-minimal approximation for effective masses of light and heavy neutrinos in the framework of a type-I seesaw mechanism with three generations of sterile Majorana neutrinos which recover the symmetry between quarks and leptons is…
We report a recent study on lepton masses within a beyond standard model with a SU(3) family symmetry model. In this scenario ordinary heavy fermions, top and bottom quarks and tau lepton become massive at tree level from Dirac See-saw…
It is shown that the hybrid MSW + VO solution of the solar neutrino problem, according to which the solar nu_e undergo matter-enhanced transitions into nu_mu, nu_tau in the Sun followed by long wave length (about 1.5 10^8 km) nu_e -> nu_mu,…
It was recently shown by the authors that the Fritzsch ansatz for the quark mass matrices prescribed at the supersymmetric grand unified scale is compatible with a moderately heavy top quark ($m_t \simeq 120-150~GeV$). Here we extend the…
The three active light neutrinos are used to explain the neutrino oscillations. The inherently bi-large mixing neutrino mass matrix and the Fritzsch type, bi-small mixing charged lepton mass matrix are assumed. By requiring the maximal…
We study the neutrino mass matrix in supersymmetric models in which the quark and charged lepton mass hierarchies and also the suppression of baryon or lepton number violating couplings are all explained by horizontal $U(1)_X$ symmetry. It…
We consider the low scale ($10$ - $100$ TeV) left-right symmetric model with "naturally" small neutrino masses generated through the inverse seesaw mechanism. The Dirac neutrino mass terms are taken to be similar to the masses of charged…
A natural solution to the fermion mass hierarchy problem suggests the existence of a partially conserved chiral symmetry. We show that this can lead to a reasonably natural solution to the solar and atmospheric neutrino problems without…
The lepton masses and mixings are studied on the basis of string inspired $SU(6)\times SU(2)_R$ model with global flavor symmetries. Provided that sizable mixings between lepton doublets $L$ and Higgsino-like fields $H_d$ with even R-parity…
We discuss neutrino masses in the framework of a minimal extension of the minimal supersymmetric standard model (MSSM) consisting of an additional single right-handed neutrino superfield $N$ with a heavy Majorana mass $M$, which induces a…
If neutrinos are to play a relevant cosmological role, they must be essentially degenerate. We study whether radiative corrections can or cannot be responsible for the small mass splittings, in agreement with all the available experimental…
We advance a method used to analyse the neutrino properties (masses and mixing) in the seesaw mechanism. Assuming the hierarchical Dirac and light neutrino masses we establish rather simple relations between the light and the heavy neutrino…
Models of neutrino masses are discussed capable of explaining in a natural way the maximal mixing between $\nu_{\mu}$ and $\nu_{\tau}$ observed by the Super-Kamiokande collaboration. For three generations of leptons two classes of such…
The radiative type-I seesaw has been already implemented to explain the lightness of Majorana neutrinos with both Majorana and Dirac heavy fermions, and the lightness of Dirac neutrinos with Dirac heavy fermions. In this work we present a…