scholarly journals POSSIBLE TEXTURES OF THE FERMION MASS MATRICES

2011 ◽  
Vol 26 (18) ◽  
pp. 2973-2995 ◽  
Author(s):  
MANMOHAN GUPTA ◽  
GULSHEEN AHUJA
Keyword(s):  
Quark Mass ◽  
Fermion Mass ◽  
Neutrino Masses ◽  
Fermion Masses ◽  
Mass Matrices

Texture specific fermion mass matrices have played an important role in understanding several features of fermion masses and mixings. In the present work, we have given an overview of all possible cases of Fritzsch-like as well as non-Fritzsch-like texture 6 and 5 zero fermion mass matrices. Further, for the case of texture 4 zero Fritzsch-like quark mass matrices, the issue of the hierarchy of the elements of the mass matrices and the role of their phases have been discussed. Furthermore, the case of texture 4 zero Fritzsch-like lepton mass matrices has also been discussed with an emphasis on the hierarchy of neutrino masses for both Majorana and Dirac neutrinos.

scholarly journals FERMION MASSES AND MIXING IN FOUR AND MORE DIMENSIONS

2006 ◽  
Vol 21 (31) ◽  
pp. 6267-6301 ◽  
Author(s):  
N. CHAMOUN ◽  
S. KHALIL
Keyword(s):  
Extra Dimensions ◽  
Quark Mass ◽  
Mass Matrix ◽  
New Physics ◽  
Fermion Mass ◽  
Superstring Theory ◽  
Quark Masses ◽  
Fermion Masses ◽  
Mass Matrices ◽  
Flavor Mixing

We give an overview of recent progress in the study of fermion mass and flavor mixing phenomena. Mass matrix ansatze are considered within the Standard Model (SM) and SUSY GUT's where some predictive frameworks based on SU(5) and SO(10) are reviewed. We describe a variety of schemes to construct quark mass matrices in extra dimensions focusing on four major classes: models with the SM residing on 3-brane, models with universal extra dimensions, models with split fermions and models with warped extra dimensions. We outline how realistic patterns of quark mass matrices could be derived from orbifold models in heterotic superstring theory. Finally, we address the fermion mass problem in intersecting D-branes scenarios, and present models with D6-branes able to give a good quantitatively description of quark masses and mixing. The role of flavor/CP violation problem as a probe of new physics is emphasized.

Texture zero mass matrices and flavor mixing of quarks and leptons

2015 ◽  
Vol 30 (28) ◽  
pp. 1550138 ◽  
Author(s):  
Harald Fritzsch
Keyword(s):  
Experimental Data ◽  
Neutrino Masses ◽  
Mixing Angle ◽  
Mixing Angles ◽  
Zero Mass ◽  
Fermion Masses ◽  
Mass Matrices ◽  
Flavor Mixing ◽  
Texture Zero ◽  
The Masses

We discuss mass matrices with four texture zeros for the quarks and leptons. The three mixing angles for the quarks and leptons are functions of the fermion masses. The results agree with the experimental data. The ratio of the masses of the first two neutrinos is given by the solar mixing angle. The neutrino masses are calculated: [Formula: see text], [Formula: see text] and [Formula: see text].

scholarly journals INSTANTON INDUCED CHARGED FERMION AND NEUTRINO MASSES IN A MINIMAL STANDARD MODEL SCENARIO FROM INTERSECTING D-BRANES

2009 ◽  
Vol 24 (32) ◽  
pp. 6035-6049 ◽  
Author(s):  
G. K. LEONTARIS
Keyword(s):  
Standard Model ◽  
Quark Mass ◽  
Majorana Neutrino ◽  
Neutrino Masses ◽  
Charged Fermion ◽  
Yukawa Couplings ◽  
Heavy Majorana Neutrino ◽  
Down Quark ◽  
Mass Matrices ◽  
Minimal Standard

String instanton Yukawa corrections from Euclidean D-branes are investigated in an effective Standard Model theory obtained from the minimal U (3)× U (2)× U (1) D-brane configuration. In the case of the minimal chiral and Higgs spectrum, it is found that superpotential contributions are induced by string instantons for the perturbatively forbidden entries of the up- and down-quark mass matrices. Analogous nonperturbative effects generate heavy Majorana neutrino masses and a Dirac neutrino texture with factorizable Yukawa couplings. For this latter case, a specific example is worked out where it is shown how this texture can reconcile the neutrino data.

scholarly journals Fermion mass hierarchies from modular symmetry

2020 ◽  
Vol 2020 (9) ◽  
Author(s):  
Simon J.D. King ◽  
Stephen F. King
Keyword(s):  
Standard Model ◽  
Fermion Mass ◽  
Neutrino Masses ◽  
Fermion Fields ◽  
Level 3

Abstract We show how quark and lepton mass hierarchies can be reproduced in the framework of modular symmetry. The mechanism is analogous to the Froggatt-Nielsen (FN) mechanism, but without requiring any Abelian symmetry to be introduced, nor any Standard Model (SM) singlet flavon to break it. The modular weights of fermion fields play the role of FN charges, and SM singlet fields with non-zero modular weight called weightons play the role of flavons. We illustrate the mechanism by analysing A4 (modular level 3) models of quark and lepton (including neutrino) masses and mixing, with a single modulus field. We discuss two examples in some detail, both numerically and analytically, showing how both fermion mass and mixing hierarchies emerge from different aspects of the modular symmetry.

scholarly journals Towards unification of quark and lepton flavors in $$A_4$$ modular invariance

2021 ◽  
Vol 81 (1) ◽  
Author(s):  
Hiroshi Okada ◽  
Morimitsu Tanimoto
Keyword(s):  
Neutrino Mass ◽  
Modular Forms ◽  
Quark Mass ◽  
Mass Matrix ◽  
Neutrino Masses ◽  
Inverted Hierarchy ◽  
Mass Matrices ◽  
The Common ◽  
Charged Leptons ◽  
The One

AbstractWe study quark and lepton mass matrices in the $$A_4$$ A 4 modular symmetry towards the unification of the quark and lepton flavors. We adopt modular forms of weights 2 and 6 for quarks and charged leptons, while we use modular forms of weight 4 for the neutrino mass matrix which is generated by the Weinberg operator. We obtain the successful quark mass matrices, in which the down-type quark mass matrix is constructed by modular forms of weight 2, but the up-type quark mass matrix is constructed by modular forms of weight 6. The viable region of $$\tau $$ τ is close to $$\tau =i$$ τ = i . Lepton mass matrices also work well at nearby $$\tau =i$$ τ = i , which overlaps with the one of the quark sector, for the normal hierarchy of neutrino masses. In the common $$\tau $$ τ region for quarks and leptons, the predicted sum of neutrino masses is 87–120 meV taking account of its cosmological bound. Since both the Dirac CP phase $$\delta _{CP}^\ell $$ δ CP ℓ and $$\sin ^2\theta _{23}$$ sin 2 θ 23 are correlated with the sum of neutrino masses, improving its cosmological bound provides crucial tests for our scheme as well as the precise measurement of $$\sin ^2\theta _{23}$$ sin 2 θ 23 and $$\delta _{CP}^\ell $$ δ CP ℓ . The effective neutrino mass of the $$0\nu \beta \beta $$ 0 ν β β decay is $$\langle m_{ee}\rangle =15$$ ⟨ m ee ⟩ = 15 –31 meV. It is remarked that the modulus $$\tau $$ τ is fixed at nearby $$\tau =i$$ τ = i in the fundamental domain of SL(2, Z), which suggests the residual symmetry $$Z_2$$ Z 2 in the quark and lepton mass matrices. The inverted hierarchy of neutrino masses is excluded by the cosmological bound of the sum of neutrino masses.

scholarly journals SU(5)×U(1)′ Models with a Vector-Like Fermion Family

Universe ◽  
2021 ◽  
Vol 7 (10) ◽  
pp. 356
Author(s):  
A. Karozas ◽  
G. K. Leontaris ◽  
I. Tavellaris
Keyword(s):  
B Meson ◽  
Low Energy ◽  
Fermion Mass ◽  
Anomaly Cancellation ◽  
Covering Group ◽  
Geometric Singularity ◽  
Mass Matrices ◽  
The Standard Model ◽  
Model Predictions

Motivated by experimental measurements indicating deviations from the Standard Model predictions, we discuss F-theory-inspired models, which, in addition to the three chiral generations, contain a vector-like complete fermion family. The analysis takes place in the context of $SU(5)\times U(1)'$ GUT embedded in an $E_8$ covering group, which is associated with the (highest) geometric singularity of the elliptic fibration. In this context, the $U(1)'$ is a linear combination of four abelian factors subjected to the appropriate anomaly cancellation conditions. Furthermore, we require universal $U(1)'$ charges for the three chiral families and different ones for the corresponding fields of the vector-like representations. Under the aforementioned assumptions, we find 192 models that can be classified into five distinct categories with respect to their specific GUT properties. We exhibit representative examples for each such class and construct the superpotential couplings and the fermion mass matrices. We explore the implications of the vector-like states in low-energy phenomenology, including the predictions regarding the B-meson anomalies. The rôle of R-parity violating terms appearing in some particular models of the above construction is also discussed.

RENORMALIZATION GROUP FLOW IN COLD AND DENSE YUKAWA THEORY

2007 ◽  
Vol 16 (09) ◽  
pp. 2806-2809 ◽  
Author(s):  
LETÍCIA F. PALHARES ◽  
EDUARDO S. FRAGA
Keyword(s):  
Renormalization Group ◽  
Fermion Mass ◽  
Zero Temperature ◽  
Renormalization Group Flow ◽  
Finite Density ◽  
Mass Effects ◽  
Fermion Masses ◽  
Group Flow ◽  
Yukawa Theory

We analyze the role of renormalization group (RG) running of the coupling and fermion masses in perturbative Yukawa theory at finite density. The dependence of the RG flow on the number of fermion flavors is discussed. Results for the fermionic contribution to the two-loop pressure at zero temperature and finite density are presented for NF = 4, and finite fermion mass effects are shown to be an important correction.

scholarly journals The mass ratios parametrization

2019 ◽  
Vol 34 (01) ◽  
pp. 1950007 ◽  
Author(s):  
U. J. Saldana-Salazar ◽  
K. M. Tame-Narvaez
Keyword(s):  
Small Mass ◽  
Standard Theory ◽  
Fermion Mass ◽  
Neutrino Masses ◽  
Flavor Symmetry ◽  
Lepton Sector ◽  
Normal Ordering ◽  
Fermion Masses ◽  
Mass Ratios ◽  
Model Independent

The observed hierarchy in the fermion masses, which imply a set of small mass ratios, is not naturally small regarding ’t Hooft’s criteria. In this work, in a model independent approach, we introduce a set of conditions by which fermion mass ratios become natural. Interestingly, these conditions demand that fermion mixing should be described by the four independent mass ratios of each fermion sector. Application of this set of conditions to the standard theory enables one to understand the mains aspects in quark and lepton mixing. This feature can be taken as a strong evidence for the existence in Nature of a flavor symmetry. Also, for this analysis to work in the lepton sector, neutrino masses should have normal ordering with the lightest neutrino mass satisfying the lower bound, [Formula: see text], making the approach testable.

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