18789156
A predictive ansatz for neutrino mixing and leptogenesis
Abstract We propose a non-SO(10) modification of the Buchmuller–Wyler ansatz for neutrino mixing and leptogenesis, in which charged lepton, Dirac and Majorana neutrino mass matrices have fewer free parameters. Predictions of this new ansatz for three light neutrino masses, three lepton flavor mixing angles, the neutrinoless double- β decay and the cosmological matter–anti-matter asymmetry are all in very good agreement with current experimental and observational data.
118486547
A shift from democratic to tri-bimaximal neutrino mixing with relatively large theta(13)
Recent neutrino oscillation data hint that the smallest neutrino mixing angle theta(13) is possible to lie in the range 5 degrees less than or similar to theta(13) less than or similar to 12 degrees. We show that reasonable perturbations to the democratic mixing pattern, which is geometrically related to the tri-bimaximal mixing pattern through an equal shift theta(*) similar or equal to 9.7 degrees of two large mixing angles, can naturally produce a nearly tri-bimaximal neutrino mixing matrix V with sufficiently large theta(13). Two especially simple but viable scenarios of V are proposed and their phenomenological consequences are discussed. (C) 2010 Elsevier B.V. All rights reserved.
14767884
Commutators of lepton mass matrices, CP violation, and matter effects in medium-baseline neutrino experiments
We introduce the commutators of lepton mass matrices to describe the phenomenon of lepton flavor mixing, and establish their relations to the effective Hamiltonians responsible for the propagation of neutrinos. The determinants of those commutators an invariant under matter effects, leading to an instructive relationship between the universal CP-violating parameters in vacuum and in matter. in the scenario of low-energy (100 MeV less than or equal toE less than or equal to1 GeV) and medium-baseline (100 km less than or equal toL less than or equal to 400 km) neutrino experiments, we illustrate the features of lepton flavor mixing and CP violation. The terrestrial matter effects on CP- and T-violating asymmetries in nu (e) nu (mu) and )over bar>(e) )over bar>(mu) neutrino oscillations are also discussed. We demonstrate that a relatively pure signal of leptonic CP violation at the percent level can be established from such medium-baseline experiments with low-energy neutrino beams.
14710000
Impact of fermion mass degeneracy on flavour mixing
We carry out a systematic analysis of flavour mixing and CP violation in the conceptually interesting limit where two quarks or leptons of the same charge are degenerate in mass. We pay some particular attention to the impact of neutrino mass degeneracy and Majorana phase degeneracy on the lepton flavour mixing matrix.
14217283
Naturalness and Testability of TeV Seesaw Mechanisms
After outlining some popular ways to go beyond the standard model so as to generate non-zero but tiny neutrino masses, I focus On several typical seesaw mechanisms and discuss how to get a balance between their theoretical naturalness and their experimental testability. Besides possible collider signatures at the Large Hadron Collider, new and non-unitary CP-violating effects are also expected to show tip in neutrino oscillations for type-I, type-(I+II), type-III and double seesaws at the TeV scale.
17156834
Theoretical Overview of Neutrino Properties
I give an overview of some basic properties of massive neutrinos. The first part of this talk is devoted to three fundamental questions about three known neutrinos and to their flavor issues -- the mass spectrum, mixing pattern and CP violation. The second part of this talk is to highlight a few hot topics at the frontiers of neutrino physics and neutrino astrophysics, including the naturalness and testability of TeV seesaw mechanisms at the LHC, effects of non-standard interactions on neutrino oscillations, flavor distributions of ultrahigh-energy cosmic neutrinos at neutrino telescopes, collective flavor oscillations of supernova neutrinos, flavor effects in thermal leptogenesis, the GSI anomaly and Moessbauer neutrino oscillations, and so on. I finally make some concluding remarks for the road ahead.
121307979
Triaxiality of the yrast states of odd-A Lu isotopes
The energy spectra and electromagnetic transition probabilities of the negative-parity yrast states in odd-A Lu isotopes (Z=71) are investigated systematically using the particle-rotor model and are compared with experimental data before and after the band crossing. It is noted that the moment of inertia of the core after the band crossing is as much a smooth function of the total angular momentum I, as that before the band crossing and can be described by the ab formula. Appreciably different are the triaxial deformations before (similar to 20 degrees) and after (similar to+10 degrees) the band crossing for Lu-161,Lu-163,Lu-165, while they are more or less similar (similar to-10 degrees) for Lu-167 determined from the calculation. [S0556-2813(99)03910-2].