Tzee-Ke Kuo

T non-conservation in three-neutrino oscillations

Abstract The effects of a T violating vacuum mixing parameter in neutrino oscillations can be enhanced by the presence of matter. However, most astrophysical neutrino experiments observe only the electron neutrino transmission probability, P ( ν e ; x → ν e ; y ), which is completely independent of the T violating phase. There is only one direct measure of this phase for three flavors and a symmetric medium such as the earth - for which we calculate some examples.

Supernova neutrinos in the light of flavor changing neutral currents

We study the effect of including flavor changing neutral currents (FCNC) in the analysis of the neutrino signal of a supernova burst. When we include the effect of the FCNC which are beyond the standard model (SM) in the study of the MSW resonant conversion, we obtain dramatic changes in the Delta m^2-sin^2(2theta) probability contours for neutrino detection.

Triangular textures for quark mass matrices

Hierarchical quark masses and small mixing angles are shown to lead to a simple triangular form for {ital U}- and {ital D}-type quark mass matrices. In the basis where one of the matrices is diagonal, each matrix element of the other is, to a good approximation, the product of a quark mass and a CKM matrix element. The physical content of a general mass matrix can be easily deciphered in its triangular form. This parametrization could serve as a useful starting point for model building. Examples of mass textures are analyzed using this method. {copyright} {ital 1999} {ital The American Physical Society}

Renormalization invariants of the neutrino mass matrix

The renormalization evolution of all parameters in the neutrino mass matrix depends only on one variable, the energy scale. This fact, coupled with rephasing considerations, leads to a set of renormalization invariants, correlating the evolution of physical parameters. For the general three flavor case, we obtain these invariants explicitly and discuss their implications.

Classification and application of triangular quark mass matrices

Abstract Any given pair of up and down quark mass matrices can be brought into the triangular form, at the same time eliminating their unphysical contents. Further, we show that every physically viable pair can always be reduced to one of ten triangular forms, which we list explicitly. When hermitian mass matrices are thus analyzed, it is found that any pattern of texture zeros translates into simple, analytic predictions for the quark mixings. Amongst possible hermitian matrices with five texture zeros, this method enables us to identify the unique pair which is favored by present data.

Effects of neutrino temperatures and mass hierarchies on the detection of supernova neutrinos

The possible outcomes of neutrino events at both Super-Kamiokande and SNO for a type-II supernova are analyzed considering the uncertainties in supernova neutrino spectra (temperature) at emission, which may complicate the interpretation of the observed events. With the input of parameters deduced from the current solar and atmospheric experiments, the consequences of direct-mass hierarchy m{sub {nu}}{sub {tau}}>>m{sub {nu}}{sub {mu}}>m{sub {nu}}{sub e} and inverted-mass hierarchy m{sub {nu}}{sub e}>m{sub {nu}}{sub {mu}}>>m{sub {nu}}{sub {tau}} are investigated. Even if the {nu} temperatures are not precisely known, we find that future experiments are likely to be able to separate the currently accepted solutions to the solar neutrino problem, large-angle Mikheyev-Smirnov-Wolfenstein (MSW), small-angle MSW, and the vacuum oscillation, as well as to distinguish between the direct and inverted mass hierarchies of the neutrinos. (c) 2000 The American Physical Society.

Solar neutrinos with three-flavor mixings

The recent{sup 71}Ga solar neutrino observation is combined with the {sup 37}Cl and Kamiokande-II observations in an analysis for neutrino masses and mixings. The allowed parameter region is found for matter enhanced mixings among all three neutrino flavors. Distortions of the solar neutrino spectrum unique to three flavors are possible and may be observed in continuing and next generation experiments.

Maximal neutrino mixing from an attractive infrared fixed point

Abstract In the Standard Model (and MSSM), renormalization effects on neutrino mixing are generally very small and the attractive fixed points are at vanishing neutrino mixing. However for multi-Higgs extensions of the Standard Model, renormalization effects on neutrino mixing can be large and nontrivial fixed points are possible. Here we examine a simple two-Higgs model. For two flavors, maximal mixing is an attractive infrared fixed point. For three flavors, the neutrino mass matrix evolves towards large off-diagonal elements at low energies. The experimentally suggested bimaximal neutrino mixing pattern is one possible attractive infrared fixed point.

INCLUSION OF

We extend our previous work on the precision electroweak tests in the Sp(6)L×U(1)Y family model to include for the first time the important vertex corrections encoded in a new variable ∊b, utilizing all the latest LEP data. We include in our analysis the one-loop EW radiative corrections due to the new bosons in terms of ∊1,b and ΔΓZ. We find that the correlation between ∊1 and ∊b makes the combined constraint much stronger than the individual ones. The model is consistent with the recent CDF result of but it; cannot accommodate mt≳195 GeV.