ρ PARAMETER CONSTRAINTS ON FOURTH GENERATION QUARK MASSES

1990 ◽  
Vol 05 (10) ◽  
pp. 743-754 ◽  
Author(s):  
V. BARGER ◽  
J. L. HEWETT ◽  
T. G. RIZZO
Keyword(s):  
Fourth Generation ◽  
Quark Masses ◽  
Quark Mixing ◽  
Mixing Matrix ◽  
The Masses ◽  
Parameter Constraints

Constraints on the masses of possible fourth generation quarks (a, υ) are obtained from measurements of the ρ parameter and the elements of the quark mixing matrix. Stringent mass limits are found when the off-diagonal elements Vtυ and Vab are large. For example, with mt=90 GeV and |Vtυ|≃0.5 we find ma,v≤ 300 GeV. Stronger constraints are obtained as mt or |Vtυ| increase.

GENERAL STUDY OF QUARK MASS MATRICES WITH FULL OFF-DIAGONAL MIXING

1992 ◽  
Vol 07 (25) ◽  
pp. 6357-6370 ◽  
Author(s):  
ROBERT E. SHROCK
Keyword(s):  
Quark Mass ◽  
Mass Matrix ◽  
General Study ◽  
Mixing Angles ◽  
Quark Masses ◽  
Rotation Matrices ◽  
Quark Mixing ◽  
Down Quark ◽  
Mass Matrices ◽  
Mixing Matrix

We study an ansatz for the quark mass matrix in which all of the nondiagonal entries are nonzero, but which still allows the quark mixing angles to be calculated in terms of ratios of quark masses and certain phases. Analytic calculations of the orthogonal rotation matrices in the up and down quark sectors and the resultant observed quark mixing matrix are presented. Comparison with experimental data is given.

scholarly journals Modular invariant A4 models for quarks and leptons with generalized CP symmetry

2021 ◽  
Vol 2021 (5) ◽  
Author(s):  
Chang-Yuan Yao ◽  
Jun-Nan Lu ◽  
Gui-Jun Ding
Keyword(s):  
Vacuum Expectation ◽  
Vacuum Expectation Value ◽  
Modular Invariant ◽  
Quark Masses ◽  
Mass Matrices ◽  
Flavor Mixing ◽  
Mixing Matrix ◽  
Free Parameters ◽  
The Masses ◽  
Cp Symmetry

Abstract We perform a systematical analysis of the A4 modular models with generalized CP for the masses and flavor mixing of quarks and leptons, and the most general form of the quark and lepton mass matrices is given. The CP invariance requires all couplings real in the chosen basis and thus the vacuum expectation value of the modulus τ uniquely breaks both the modular symmetry and CP symmetry. The phenomenologically viable models with minimal number of free parameters and the results of fit are presented. We find 20 models with 7 real free parameters that can accommodate the experimental data of lepton sector. We then apply A4 modular symmetry to the quark sector to explain quark masses and CKM mixing matrix, the minimal viable quark model is found to contain 10 free real parameters. Finally, we give two predictive quark-lepton unification models which use only 16 real free parameters to explain the flavor patterns of both quarks and leptons.

scholarly journals Constraints on the quark mixing matrix with vector-like quarks

2020 ◽  
Vol 960 ◽  
pp. 115208
Author(s):  
Drona Vatsyayan ◽  
Anirban Kundu
Keyword(s):  
Quark Mixing ◽  
Mixing Matrix

The quark mixing matrix in a composite model

1983 ◽  
Vol 149 (2) ◽  
pp. 273-285 ◽  
Author(s):  
H Katsumata ◽  
Y Tomozawa
Keyword(s):  
Composite Model ◽  
Quark Mixing ◽  
Mixing Matrix

scholarly journals TWO PREDICTIVE SUPERSYMMETRIC S3×Z2 MODELS FOR THE QUARK MASS MATRICES

2005 ◽  
Vol 20 (16) ◽  
pp. 1217-1225 ◽  
Author(s):  
LUÍS LAVOURA ◽  
ERNEST MA
Keyword(s):  
Quark Mass ◽  
Quark Mixing ◽  
Mass Matrices ◽  
Mixing Matrix ◽  
Simple Models

We propose two simple models for the quark mass matrices which may be implemented through an S3×Z2 symmetry in a supersymmetric context. Each model has eight parameters and, therefore, makes two independent predictions for the quark mixing matrix. The first model predicts [Formula: see text] and [Formula: see text]. The second model, in which the forms of the up-type-quark and down-type-quark mass matrices are interchanged relative to the first one, predicts |Vub/Vcb|~0.11 and |Vtd/Vts|~0.33. Both models have sin 2β~0.5.

Simple quark mass matrices and mixing

1993 ◽  
Vol 71 (3-4) ◽  
pp. 172-174
Author(s):  
B. Margolis ◽  
S. Punch
Keyword(s):  
Quark Mass ◽  
Quark Masses ◽  
Down Quark ◽  
Mass Matrices ◽  
Geometric Progressions ◽  
Mixing Matrix ◽  
Two Parameters

We present mass matrices identical in form for both the up and down quark families, with the following remarkable properties. Both up and down quark masses, at a scale of 1 GeV, are well-approximated by geometric progressions. The five known quark masses and the Kobayashi–Maskawa (KM) mixing matrix agree with experiment. The KM matrix is expressed in terms of only two parameters. We give the KM matrix in the Wolfenstein form.

scholarly journals Discrete symmetry and CP phase of the quark mixing matrix

2005 ◽  
Vol 620 (3-4) ◽  
pp. 151-155 ◽  
Author(s):  
Shao-Long Chen ◽  
Ernest Ma
Keyword(s):  
Discrete Symmetry ◽  
Quark Mixing ◽  
Mixing Matrix

Rosen-type derivation of the quark mixing matrix in three- and four-generation schemes

1988 ◽  
Vol 38 (3) ◽  
pp. 970-979 ◽  
Author(s):  
Takemi Hayashi ◽  
Ryuichi Najima ◽  
Morimitsu Tanimoto ◽  
Seiichi Wakaizumi
Keyword(s):  
Quark Mixing ◽  
Mixing Matrix
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