Large Right Handed Rotations, Neutrino Oscillations and Proton Decay

Right Handed (RH) rotations are not observable in the standard model (SM). The freedom is used to give the phenomenologically correct mass matrices all kind of different forms and this is one of the reasons for the proliferation of models for the fermionic masses. The SM must be however extended and in most extensions, RH currents appear at higher energy scales. At those energies the RH rotations are not irrelevant any more, they can affect neutrino oscillations, proton decay, baryon assymetry, R-parity violating interactions etc. We study possible implications of large RH mixing in GUTs. Those are interesting not only because large mixing induce large effects. They are intimately related to large lepton mixing in GUTs, via a relation between LH mixing of the leptons and the RH ones of the d-quarks ,(``$d - \ell$ duality'') and can change considerably the branching ratios of proton decay. Observation of proton decay channels as well as neutrino oscillations will teach us about RH rotations and will reduce, therefore, considerably the freedom in the fermionic mass matrices. Some interesting examples are studied in detail. In particular a new $E_6$ model which realizes naturally a $d$ - $\ell$ duality by mixing with exotic $E_6$ fermions.Comment: 7 pages, no figuers; talk at the TAUP99, to be published in JHEP; LaTeX margins correcte

Large Quark Rotations Neutrino Oscillations and Proton Decay

The large freedom in the SM fermionic mass matrices allows for large LH and LH quark rotations. This is a natural possibility in view of the observed large leptonic mixing. Proton decay and especially its gauge mediated decay is sensitive also to those mixing angles which are non-relevant in the SM. A model with realistic mass matrices and large rotations is presented.. It is shown that the large leptonic mixing leads to enhancement of the proton decay branching ratios involving muons.Comment: 4 pages, talk given at the SUSY'01 (held in JINR, Dubna, Russia, 11-17 June 2001), to appear in the Proceeding

Can One Phase Induce All CP Violations Including Leptogenesis?

In the framework of a SUSY SO(10) model a phase is generated spontaneously for the B-L breaking VEV. Fitting this phase to the observed CP violating K,B decays all other CP breaking effects are uniquely predicted. In particular, the amount of Leptogenesis can be explicitly calculated and found to be in the right range and sign for the BAU.Comment: 12 pages, version published in PL

Massive Neutrinos and Lepton Mixing in Unified Theories

The recent GUT (x SUSY) models which can predict the neutrino properties are reviewed.Comment: 8 pages, Talk presented at the XVI International Workshop on Weak Interactions and Neutrinos, Capri, 199

The Berkovits Method for Conformally Invariant Non-linear Sigma-models on G/H

We discuss 2-dimmensional non-linear sigma-models on the Kaehler manifold G/H in the first order formalisim. Using the Berkovits method we explicitly construct the G-symmetry currents and primaries, when G/H are irreducible. It is a variant of the Wakimoto realization of the affine Lie algebra using a particular reducible Kaehler manifold G/U(1)^r with r the rank of G.Comment: 13 page

The four-fermi coupling of the supersymmetric non-linear sigma-model on G/S\otimesU(1)^k

The reducible K\"ahler coset space G/S\otimesU(1)^k is discussed in a geometrical approach. We derive the formula which expresses the Riemann curvature of the reducible K\"ahler coset space in terms of its Killing vectors. The formula manifests the group structure of G. On the basis of this formula we establish an algebraic method to evaluate the four-fermi coupling of the supersymmetric non-linear sigma-model on G/S\otimesU(1)^k at the low-energy limit. As an application we consider the supersymmetric non-linear sigma-model on E_7/SU(5)\otimesU(1)^3 which contains the three families of {10} + {5^*} + {1} of SU(5) as the pseudo NG fermions. The four-fermi coupling constants among diffferent families of the fermions are explicitly given at the low-energy limit.Comment: 33 pages, 1 figure, to appear in Nuclear Physics