Related papers: A minimal three generation seesaw scenario for LSN…
We show that a double seesaw framework for neutrino masses with $\mu-\tau$ exchange symmetry can lead to one of the righthanded seesaw partners of the light neutrinos being massless. This can play the role of a light sterile neutrino,…
Recent results from SuperKamiokande and SNO experiments have set severe constraints on possible mixings of a light sterile neutrino, \nu_s, with the three active species required for a simultaneous explanation of the solar, atmospheric and…
We investigate a minimal extension of the standard model in which the only new ingredient is the sterile neutrinos. We do not introduce extra Higgs multiplets or high dimensional effective operators to induce mass terms for the active…
We study the special features emerging from a three lepton generation analysis of the available neutrino oscillation data (solar, atmospheric and LSND). First we find that it is possible to explain all three sets of data in terms of the…
The Standard Model augmented by the presence of gauge-singlet right-handed neutrinos proves to be an ideal scenario for accommodating nonzero neutrino masses. Among the new parameters of this ``New Standard Model'' are right-handed neutrino…
We consider the so-called "eV seesaw" scenario, with right-handed Majorana mass $M_R$ at eV order, extended to four lepton generations. The fourth generation gives a heavy pseudo-Dirac neutral lepton, which largely decouples from other…
We propose a simple model of the neutrino mass matrix which can explain the solar and atmospheric neutrino problems in a 3($\nu_L + \nu_R$) framework. Assuming that only two right-handed neutrinos are heavy and a Dirac mass matrix has a…
If an exact $\mu\leftrightarrow \tau$ symmetry is the explanation of the maximal atmospheric neutrino mixing angle, it has interesting implications for origin of matter via leptogenesis in models where small neutrino masses arise via the…
We study the minimal extended seesaw mechanism with one sterile neutrino in a 3+1 framework using modular $S_3$ symmetry. The active-sterile neutrino models are classified based on the assignments of $S_3$ representations and modular…
In the context of the seesaw mechanism, it is natural that the large solar and atmospheric neutrino mixing angles originate separately from large 2 by 2 mixings in the neutrino and charged-lepton sectors, respectively, and large mixing in…
We propose a model for lepton mass matrices based on the seesaw mechanism, a complex scalar gauge singlet and a horizontal symmetry $S_3 \times \mathbbm{Z}_2$. In a suitable weak basis, the charged-lepton mass matrix and the neutrino Dirac…
We present a gauge model for the bimaximal mixing pattern among the neutrinos that explains both the atmospheric and solar neutrino data via large angle vacuum oscillation among the three known neutrinos. The model does not include…
Motivated by the recent Super-Kamiokande experiment on atmospheric and solar neutrino oscillation we propose a see-saw model of three generations of neutrinos based on the gauge group $SU(2)_{L}\times U(1)_{Y}$ with discrete symmetries…
We discuss possibility of describing solar, atmospheric and LSND results with four neutrinos forming two quasi-degenerate pairs. The simplest versions of this 2+2 scheme with either $\nu_e$ or $\nu_\mu$ mixing exclusively with sterile…
The recent recomputation of the neutrino fluxes from nuclear reactors relaxes the tension between the LSND and MiniBooNE anomalies and disappearance data when interpreted in terms of sterile neutrino oscillations. The simplest extension of…
We enlarge the lepton sector of the Standard Model by adding to it two right-handed neutrino singlets, and propose a model based on the seesaw mechanism and on the lepton number $\bar L = L_e - L_\mu - L_\tau$. The model is innovative from…
Extending the Standard Model with right-handed neutrinos provides a minimal explanation for both light neutrino masses (through the type-I seesaw mechanism) and the baryon asymmetry of our universe (through leptogenesis). We map here for…
We consider an extension of the Standard Model with three right-handed (RH) neutrinos and a Dirac pair of extra sterile neutrinos, odd under a discrete $Z_2$ symmetry, in order to have left-right symmetry in the neutrino content and obtain…
The measured values for the mixture angles in neutrino oscillations suggest the existence of a symmetry of interchange of flavor between muon and tau neutrinos. Using this symmetry we analyzed the minimal seesaw model for neutrino masses,…
We propose the Littlest Seesaw (LS) model consisting of just two right-handed neutrinos, where one of them, dominantly responsible for the atmospheric neutrino mass, has couplings to $(\nu_e,\nu_{\mu},\nu_{\tau})$ proportional to $(0,1,1)$,…