Quark Mass Hierarchies, Flavor Mixing and Maximal CP-Violation

Flavor mixing and the quark mass spectrum are intimately related. In view of the observed strong hierarchy of the quark and lepton masses and of the flavor mixing angles it is argued that the description of flavor mixing must take this into account. One particular interesting way to describe the flavor mixing emerges, which is particularly suited for models of quark mass matrices based on flavor symmetries. We conclude that the unitarity triangle important for $B$ physics should be close to or identical to a rectangular triangle. $CP$ violation is maximal in this sense.Comment: 21 latex page

The breaking of the flavour permutational symmetry: Mass textures and the CKM matrix

Different ansaetze for the breaking of the flavour permutational symmetry according to S(3)L X S(3)R in S(2)L X S(2) give different Hermitian mass matrices of the same modified Fritzsch type, which differ in the symmetry breaking pattern. In this work we obtain a clear and precise indication on the preferred symmetry breaking scheme from a fit of the predicted theoretical Vckm to the experimentally determined absolute values of the elements of the CKM matrix. The preferred scheme leads to simple mass textures and allows us to compute the CKM mixing matrix, the Jarlskog invariant J, and the three inner angles of the unitarity triangle in terms of four quark mass ratios and only one free parameter: the CP violating phase Phi. Excellent agreement with the experimentally determined absolute values of the entries in the CKM matrix is obtained for Phi = 90 deg. The corresponding computed values of the Jarlskog invariant and the inner angles are J = 3.00 X 10^-5, alpha= 84 deg, beta= 24 deg and gamma =72 deg in very good agreement with current data on CP violation in the neutral kaon-antikaon system and oscillations in the B-Bbar system.Comment: 21 pages, 1 fig. Content enlarged, references added and typos corrected. To be published in Phys Rev

Maximal Neutrino Mixing and Maximal CP Violation

We propose a phenomenological model of lepton mixing and CP violation based on the flavor democracy of charge leptons and the mass degeneracy of neutrinos. A nearly bi-maximal flavor mixing pattern, which is favored by current data on atmospheric and solar neutrino oscillations, emerges naturally from this model after explicit symmetry breaking. The rephasing-invariant strength of CP or T violation can be as large as one percent, leading to significant probability asymmetries between \nu_\mu \to \nu_e and \bar{\nu}_\mu \to \bar{\nu}_e (or \nu_e \to \nu_\mu) transitions in the long-baseline neutrino experiments.Comment: LaTex 12 pages (2 figures included

Implications of the KamLAND Measurement on the Lepton Flavor Mixing Matrix and the Neutrino Mass Matrix

We explore some important implications of the KamLAND measurment on the lepton flavor mixing matrix $V$ and the neutrino mass matrix $M$. The model-independent constraints on nine matrix elements of $V$ are obtained to a reasonable degree of accuracy. We find that nine two-zero textures of $M$ are compatible with current experimental data, but two of them are only marginally allowed. Instructive predictions are given for the absolute neutrino masses, Majorana phases of CP violation, effective masses of the tritium beta decay and neutrinoless double beta decay.Comment: RevTex 15 pages (4 PS figures included

Prospects and status of quark mass renormalization in three-flavour QCD

We present the current status of a revised strategy to compute the running of renormalized quark masses in QCD with three flavours of massless O(a) improved Wilson quarks. The strategy employed uses the standard finite-size scaling method in the Schr\"odinger functional and accommodates for the non-perturbative scheme-switch which becomes necessary at intermediate renormalized couplings as discussed in [arXiv:1411.7648].Comment: 7 pages, 3 figures, 1 table; Proceedings of the 33rd International Symposium on Lattice Field Theory, 14-18 July 2015, Kobe, Japa

Quark masses and mixings in the RS1 model with a condensing 4th generation

We study the hierarchy of quark masses and mixings in a model based on a 5-dimensional spacetime with constant curvature of Randall-Sundrum type with two branes, where the Electroweak Symmetry Breaking is caused dynamically by the condensation of a 4th generation of quarks, due to underlying physics from the 5D bulk and the first KK gluons. We first study the hierarchy of quark masses and mixings that can be obtained from purely adjusting the profile localizations, finding that realistic masses are not reproduced unless non trivial hierarchies of underlying 4-fermion interactions from the bulk are included. Then we study global U(1) symmetries that can be imposed in order to obtain non-symmetric modified Fritzsch-like textures in the mass matrices that reproduce reasonably well quark masses and CKM mixings.Comment: Minor changes. Version accepted for publication in JHE

Almost Maximal Lepton Mixing with Large T Violation in Neutrino Oscillations and Neutrinoless Double Beta Decay

We point out two simple but instructive possibilities to construct the charged lepton and neutrino mass matrices, from which the nearly bi-maximal neutrino mixing with large T violation can naturally emerge. The two lepton mixing scenarios are compatible very well with current experimental data on solar and atmospheric neutrino oscillations, and one of them may lead to an observable T-violating asymmetry between \nu_\mu --> \nu_e and \nu_e --> \nu_\mu transitions in the long-baseline neutrino oscillation experiments. Their implications on the neutrinoless double beta decay are also discussed.Comment: RevTex 15 pages (2 PS figures

Hierarchy and Up-Down Parallelism of Quark Mass Matrices

In view of the quark mass hierarchy and in the assumption of the up-down parallelism, we derive two phenomenologically-favored patterns of Hermitian quark mass matrices from the quark flavor mixing matrix. We compare one of them with two existing {\it Ans$\it\ddot{a}$tze} proposed by Rosner and Worah and by Roberts {\it et al}, and find that only the latter is consistent with the present experimental data.Comment: RevTex 9 pages. Accepted for publication in Phys. Rev.

Hierarchical Quark Mass Matrices

I define a set of conditions that the most general hierarchical Yukawa mass matrices have to satisfy so that the leading rotations in the diagonalization matrix are a pair of (2,3) and (1,2) rotations. In addition to Fritzsch structures, examples of such hierarchical structures include also matrices with (1,3) elements of the same order or even much larger than the (1,2) elements. Such matrices can be obtained in the framework of a flavor theory. To leading order, the values of the angle in the (2,3) plane (s_{23}) and the angle in the (1,2) plane (s_{12}) do not depend on the order in which they are taken when diagonalizing. We find that any of the Cabbibo-Kobayashi-Maskawa matrix parametrizations that consists of at least one (1,2) and one (2,3) rotation may be suitable. In the particular case when the s_{13} diagonalization angles are sufficiently small compared to the product s_{12}s_{23}, two special CKM parametrizations emerge: the R_{12}R_{23}R_{12} parametrization follows with s_{23} taken before the s_{12} rotation, and vice versa for the R_{23}R_{12}R_{23} parametrization.Comment: LaTeX, 19 pages. References added, minor changes in text. Version published in Phys. Rev.

Universal Texture of Quark and Lepton Mass Matrices and a Discrete Symmetry Z_3

Recent neutrino data have been favourable to a nearly bimaximal mixing, which suggests a simple form of the neutrino mass matrix. Stimulated by this matrix form, a possibility that all the mass matrices of quarks and leptons have the same form as in the neutrinos is investigated. The mass matrix form is constrained by a discrete symmetry Z_3 and a permutation symmetry S_2. The model, of course, leads to a nearly bimaximal mixing for the lepton sectors, while, for the quark sectors, it can lead to reasonable values of the CKM mixing matrix and masses.Comment: 24 pages, RevTEX, no figure, some references and comments were adde