64 research outputs found
Quark Mass Matrices with Four and Five Texture Zeroes, and the CKM Matrix, in terms of Mass Eigenvalues
Using the triangular matrix techniques of Kuo et al and Chiu et al for the
four and five texture zero cases, with vanishing (11) elements for U and D
matrices, it is shown, from the general eigenvalue equations and hierarchy
conditions, that the quark mass matrices, and the CKM matrix can be expressed
(except for the phases) entirely in terms of quark masses. The matrix
structures are then quite simple and transparent. We confirm their results for
the five texture zero case but find, upon closer examination of all the CKM
elements which our results provide, that six of their nine patterns for the
four texture zero case are not compatible with experiments. In total, only one
five-texture zero and three four-texture zero patterns are allowed.Comment: 15 pages, 3 table
Prospects for Direct CP Violaton in Exclusive and Inclusive Charmless B decays
Within the Standard Model, CP rate asymmetries for could
reach 10%. With strong final state phases, they could go up to 20--30%, even
for mode which would have opposite sign. We can account for
, and rate data with new physics enhanced
color dipole coupling and destructive interference. Asymmetries could reach
40--60% for and modes and are all of the same sign. We are
unable to account for rate. Our inclusive study supports our
exclusive results.Comment: Minor changes, correct a small bug in Fig. 1(b). Version to appear in
Phys. Rev. Let
Symmetric Textures in SO(10) and LMA Solution for Solar Neutrinos
We analyze a model based on SUSY SO(10) combined with SU(2) family symmetry
and symmetric mass matrices constructed by the authors recently. Previously,
only the parameter space for the LOW and vacuum oscillation (VO) solutions was
investigated. We indicate in this note the parameter space which leads to large
mixing angle (LMA) solution to the solar neutrino problem with a slightly
modified effective neutrino mass matrix. The symmetric mass textures arising
from the left-right symmetry breaking and the SU(2) symmetry breaking give rise
to very good predictions for the quark and lepton masses and mixing angles. The
prediction of our model for the |U_{e\nu_{3}}| element in the
Maki-Nakagawa-Sakata (MNS) matrix is close to the sensitivity of current
experiments; thus the validity of our model can be tested in the near future.
We also investigate the correlation between the |U_{e\nu_{3}}| element and
\tan^{2}\theta_{\odot} in a general two-zero neutrino mass texture.Comment: RevTeX4; 9 pages; 1 figur
Hermitian quark mass matrices with four texture zeros
We provide a complete and systematic analysis of hermitian, hierarchical
quark mass matrices with four texture zeros. Using triangular mass matrices,
each pattern of texture zeros is readily shown to lead to a definite relation
between the CKM parameters and the quark masses. Nineteen pairs are found to be
consistent with present data, and one other is marginally acceptable. In
particular, no parallel structure between the up and down mass matrices is
found to be favorable with data.Comment: 18 pages, no figure, references [8] and [10] adde
Can the SO(10) Model with Two Higgs Doublets Reproduce the Observed Fermion Masses?
It is usually considered that the SO(10) model with one 10 and one 126 Higgs
scalars cannot reproduce the observed quark and charged lepton masses. Against
this conventional conjecture, we find solutions of the parameters which can
give the observed fermion mass spectra. The SO(10) model with one 10 and one
120 Higgs scalars is also discussed.Comment: 7 pages, 1 figure, REVTe
Detailed Analysis of Proton Decay Rate in the Minimal Supersymmetric SO(10) Model
We consider the minimal supersymmetric SO(10) model, where only one {\bf 10}
and one Higgs multiplets have Yukawa couplings with matter
multiplets. This model has the high predictive power for the Yukawa coupling
matrices consistent with the experimental data of the charged fermion mass
matrices, and all the Yukawa coupling matrices are completely determined once a
few parameters in the model are fixed. This feature is essential for definite
predictions to the proton decay rate through the dimension five operators. We
analyze the proton decay rate for the dominant decay modes by including as many free parameters as possible and varying them.
There are two free parameters in the Yukawa sector, while five in the Higgsino
sector. It is found that an allowed region exists when the free parameters in
the Higgs sector are tuned so as to cancel the proton decay amplitude. The
resultant proton lifetime is proportional to and the allowed
region eventually disappears as becomes large.Comment: 15 pages, 3 figures; the version to appear in JHE
CP Violation for Leptons at Higher Energy Scales
The phase convention independent measure of CP violation for three
generations of leptons is evaluated at different energy scales. Unlike in the
quark sector, this quantity does not vary much between the weak and the grand
unification scales. The behavior of the measure of CP violation in the Standard
Model is found to be different from that in the extensions of the Standard
Model.Comment: 10 pages, 2 figures, references added, typos correcte
SO(10) GUT and Quark-Lepton Mass Matrices
The phenomenological model that all quark and lepton mass matrices have the
same zero texture, namely their (1,1), (1,3) and (3,1) components are zeros, is
discussed in the context of SO(10) Grand Unified Theories (GUTs). The mass
matrices of type I for quarks are consistent with the experimental data in the
quark sector. For the lepton sector, consistent fitting to the data of neutrino
oscillation experiments force us to use the mass matrix for the charged leptons
which is slightly deviated from type I. Given quark masses and charged lepton
masses, the model includes 19 free parameters, whereas the SO(10) GUTs gives 16
constrained equations. Changing the remaining three parameters freely, we can
fit all the entries of the CKM quark mixing matrix and the MNS lepton mixing
matrix, and three neutrino masses consistently with the present experimental
data.Comment: 32pp, REV TeX, 12 EPS Figure
Evolution of the Yukawa coupling constants and seesaw operators in the universal seesaw model
The general features of the evolution of the Yukawa coupling constants and
seesaw operators in the universal seesaw model with det M_F=0 are investigated.
Especially, it is checked whether the model causes bursts of Yukawa coupling
constants, because in the model not only the magnitude of the Yukawa coupling
constant (Y_L^u)_{33} in the up-quark sector but also that of (Y_L^d)_{33} in
the down-quark sector is of the order of one, i.e., (Y_L^u)_{33} \sim
(Y_L^d)_{33} \sim 1. The requirement that the model should be calculable
perturbatively puts some constraints on the values of the intermediate mass
scales and tan\beta (in the SUSY model).Comment: 21 pages, RevTex, 10 figure
Seesaw mechanism in three flavors
We advance a method used to analyse the neutrino properties (masses and
mixing) in the seesaw mechanism. Assuming the hierarchical Dirac and light
neutrino masses we establish rather simple relations between the light and the
heavy neutrino parameters in the favored region of the solar and the
atmospheric neutrino experiments. A empirical condition satisfied by the RH
mixing angles is obtained.Comment: 19 pages. Acceptted by Phys. Rev. D The part about the neutrino
experiments is selected as a single section. The mistakes in spelling and
grammer are corrected. Also, some equations are neewly numbere
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