12453573
Resonant conversion of massless neutrinos in supernovae.
It has been noted for a long time that, in some circumstances, massless neutrinos may be mixed in the leptonic charged current. Conventional neutrino oscillation searches in vacuum are insensitive to this mixing. We discuss the effects of resonant massless-neutrino conversions in the dense ! 
17937629
Limits on the non-standard interactions of neutrinos from e+e− colliders
Abstract We provide an effective Lagrangian analysis of contact non-standard interactions of neutrinos with electrons, which can be effectively mediated by extra particles, and examine the associated experimental limits. At present, such interactions are strongly constrained only for ν μ : the bounds are loose for ν e and absent for ν τ . We emphasize the unique role played by the reaction e + e − →ν ν γ in providing direct constraints on such non-standard interactions.
14098722
Predictive Grand Unified Textures for Quark and Neutrino Masses and Mixings
Abstract We propose new textures for the fermion Yukawa matrices which are generalizations of the so-called Stech ansatz. We discuss how these textures can be realized in supersymmetric grand unified models with horizontal symmetry SU(3) H among the fermion generations. In this framework the mass and mixing hierarchy of fermions (including neutrinos) can emerge in a natural way. We emphasize the central role played by the SU(3) H adjoint Higgs field which reduces SU(3) H to U(2) H at the GUT scale. A complete SO(10)×SU(3) H model is presented in which the desired Yukawa textures can be obtained by symmetry reasons. The phenomenological implications of these textures are thoroughly investigated. Among various realistic possibilities for the Clebsch factors between the quark and lepton entries, we find three different solutions which provide excellent fits of the quark masses and CKM mixing angles. Interestingly, all these solutions predict the correct amount of CP violation via the CKM mechanism, and, in addition, lead to an appealing pattern of the neutrino masses and mixing angles. In particular, they all predict nearly maximal 23 mixing and small 12 mixing in the lepton sector, respectively, in the range needed for the explanation of the atmospheric and solar neutrino anomaly.
14842705
'Just so' oscillation: As just as MSW?
Abstract The long wavelength (just-so) neutrino oscillation is reconsidered as a solution to the solar neutrino problem, in the context of various solar models with different original fluxes of relevant components (boron, beryllium neutrinos etc.). In the light of the presently updated results of the four solar neutrino experiments, the data fit in this scenario substantially improves and becomes almost as good as in the MSW scenario. Surprising result of our analysis is that the best data fit is achieved when the oscillation occurs only between the two neutrino states: switching on the oscillation into third neutrino increases the χX 2 value. Namely, by considering the vacuum oscillation scenario in the three-neutrino system (4 parameters), we find out that the minimum of χX 2 is always achieved in the two parameter subspace in which actually only two neutrino states oscillate. The possible implications of this observation for the neutrino mass matrix textures are also discussed.
7635713
Phenomenology of the triplet seesaw mechanism with gauge and Yukawa mediation of SUSY breaking
Abstract We thoroughly discuss a new supersymmetric grand unified scenario of the triplet seesaw mechanism where the exchange of heavy SU ( 2 ) W triplet states generates both neutrino masses and soft supersymmetry breaking terms. This framework, recently proposed by us in a previous work, is highly predictive since it contains only three free parameters connecting low-energy neutrino parameters, lepton and quark flavour violation, sparticle and Higgs boson spectra and electroweak symmetry breakdown. These three parameters are the triplet mass M T , the effective supersymmetry breaking scale B T and a coupling constant λ . We perform a complete analysis of the parameter space taking into account the present experimental constraints and considering different types of neutrino spectrum. A special emphasis is given to the particular features of the sparticle and Higgs spectra and to the model independent predictions obtained for the processes μ → e X , μ → e conversion in nuclei, τ → e Y and τ → μ Y ( X = γ , e e , Y = γ , e e , μ μ ). In the appendices, we present some technical aspects relevant for our analysis.
17698502
Neutrino magnetic moment and solar neutrino experiments
Abstract We have studied the effect of a non-vanishing neutrino magnetic moment ( μ ν ) on the ν x (x = e , μ , π ) elastic scattering off electrons for the Super-Kamiokande detector. The bounds on the μ ν we have obtained are comparable to that extracted from laboratory experiments. Furthermore, we outline the potential of the Borexino experiment which may be sensitive to neutrino magnetic moments ⪅ 10 −10 μ B . In our analysis we have considered both cases of Majorana and Dirac neutrinos.
15179667
Rigorous treatment of the lattice renormalization problem of fB.
The B-meson decay constant can be measured on the lattice using a 1/m b expansion. To relate the physical quantity to Monte Carlo data one has to know the renormalizaton coefficient Z between the lattice operators and their continuum counterparts. We come back to this computation to resolve discrepancies found in previous calculations. We define and discuss in detail the renormalization procedure that allows the (perturbative) computation of Z. Comparing the one-loop calculations in the effective Lagrangian approach with the direct two-loop calculation of the two-point B-meson correlator in the limit of large b-quark mass, we prove that the two schemes give consistent results to order α s