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 Neutrino masses, vacuum stability and quantum gravity prediction for the mass of the top quark

2021 ◽  
Vol 2021 (1) ◽  
Author(s):  
Guillem Domènech ◽  
Mark Goodsell ◽  
Christof Wetterich
Keyword(s):  
Quantum Gravity ◽  
Top Quark ◽  
Quark Mass ◽  
Scalar Potential ◽  
Planck Scale ◽  
Neutrino Masses ◽  
Top Quark Mass ◽  
Vacuum Stability ◽  
Intermediate Scale ◽  
Yukawa Couplings

Abstract A general prediction from asymptotically safe quantum gravity is the approximate vanishing of all quartic scalar couplings at the UV fixed point beyond the Planck scale. A vanishing Higgs doublet quartic coupling near the Planck scale translates into a prediction for the ratio between the mass of the Higgs boson MH and the top quark Mt. If only the standard model particles contribute to the running of couplings below the Planck mass, the observed MH∼ 125 GeV results in the prediction for the top quark mass Mt∼ 171 GeV, in agreement with recent measurements. In this work, we study how the asymptotic safety prediction for the top quark mass is affected by possible physics at an intermediate scale. We investigate the effect of an SU(2) triplet scalar and right-handed neutrinos, needed to explain the tiny mass of left-handed neutrinos. For pure seesaw II, with no or very heavy right handed neutrinos, the top mass can increase to Mt ∼ 172.5 GeV for a triplet mass of M∆ ∼ 108GeV. Right handed neutrino masses at an intermediate scale increase the uncertainty of the predictions of Mt due to unknown Yukawa couplings of the right-handed neutrinos and a cubic interaction in the scalar potential. For an appropriate range of Yukawa couplings there is no longer an issue of vacuum stability.

scholarly journals FERMION-BOSON LOOPS WITH BILINEAR R-PARITY VIOLATION LEADING TO MAJORANA NEUTRINO MASS AND MAGNETIC MOMENTS

2008 ◽  
Vol 17 (01) ◽  
pp. 276-281 ◽  
Author(s):  
MAREK GÓŹDŹ ◽  
WIESŁAW A. KAMIŃSKI
Keyword(s):  
Standard Model ◽  
Supersymmetric Standard Model ◽  
Minimal Supersymmetric Standard Model ◽  
Parity Violation ◽  
Magnetic Moments ◽  
Majorana Neutrino ◽  
Feynman Diagrams ◽  
Neutrino Masses ◽  
Analytic Expressions ◽  
Majorana Neutrino Mass

We present analytic expressions corresponding to a set of one loop Feynman diagrams, built within R-parity violating (RpV) minimal supersymmetric standard model (MSSM). Diagrams involve both bilinear and trilinear RpV couplings and represent Majorana neutrino masses and magnetic moments.

scholarly journals A String-Inspired Ansatz for Quark Masses and Mixing

1997 ◽  
Vol 12 (08) ◽  
pp. 561-571 ◽  
Author(s):  
Tatsuo Kobayashi ◽  
Zhi-Zhong Xing
Keyword(s):  
Quark Mass ◽  
Fine Tuning ◽  
Superstring Theory ◽  
Quark Masses ◽  
Gauge Symmetries ◽  
Down Quark ◽  
Mass Matrices ◽  
Renormalization Group Equations ◽  
Flavor Mixing ◽  
Good Agreement

We propose a simple but realistic pattern of quark mass matrices at the string scale, which can be derived from orbifold models of superstring theory with no use of gauge symmetries. This pattern is left–right symmetric and preserves the structural parallelism between up and down quark sectors. Its phenomenological consequences on flavor mixing and CP-violation are confronted with current experiments at the weak scale by using the renormalization group equations in the framework of minimal supersymmetric standard model. We find that good agreement is achievable without fine-tuning.

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 NEUTRINO MASS AND THE STANDARD MODEL

2013 ◽  
Vol 28 (05) ◽  
pp. 1350010 ◽  
Author(s):  
F. R. KLINKHAMER
Keyword(s):  
Standard Model ◽  
Neutrino Mass ◽  
Grand Unification ◽  
Neutrino Masses ◽  
Ultimate Explanation ◽  
The Standard Model ◽  
Interaction Term ◽  
Minimal Standard ◽  
First Time ◽  
Higgs Fields

It is pointed out (not for the first time) that the minimal Standard Model, without additional gauge-singlet right-handed neutrinos or isotriplet Higgs fields, allows for nonvanishing neutrino masses and mixing. The required interaction term is non-renormalizable and violates B-L conservation. The ultimate explanation of this interaction term may or may not rely on grand unification.

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 Oscillating Neutrinos and Majorana Neutrino Masses

Universe ◽  
2020 ◽  
Vol 6 (2) ◽  
pp. 29
Author(s):  
Harald Fritzsch
Keyword(s):  
Beta Decay ◽  
Neutrino Mass ◽  
Neutrinoless Double Beta Decay ◽  
Majorana Neutrino ◽  
Double Beta Decay ◽  
Neutrino Masses ◽  
Quark Masses ◽  
Mass Matrices ◽  
The Matrix ◽  
Flavor Mixing

We discuss the mass matrices with texture zeros for the quarks and leptons. The flavor mixing angles for the quarks are functions of the quark masses and can be calculated. The results agree with the experimental data. The texture zero mass matrices for the leptons and the see-saw mechanism are used to derive relations between the matrix elements of the lepton mixing matrix and the ratios of the neutrino masses. Using the measured neutrino mass differences, the neutrino masses can be calculated. The neutrinoless double beta decay is discussed. The effective Majorana neutrino mass, describing the neutrinoless double beta decay, can be calculated—it is about 4.6 meV. The present experimental limit is at least twenty times larger.

scholarly journals Parameter-independent quark mass relation in the U(3) × U(3)′ model

2018 ◽  
Vol 33 (39) ◽  
pp. 1850230
Author(s):  
Yoshio Koide ◽  
Hiroyuki Nishiura
Keyword(s):  
Charged Lepton ◽  
Quark Mass ◽  
Mass Matrix ◽  
Mass Relation ◽  
Family Symmetry ◽  
Quark Masses ◽  
Down Quark ◽  
Mass Matrices ◽  
Additional Input ◽  
Matrix Formula

Recently, we have proposed a quark mass matrix model based on U(3) × U(3)[Formula: see text] family symmetry, in which up- and down-quark mass matrices [Formula: see text] and [Formula: see text] are described only by complex parameters [Formula: see text] and [Formula: see text], respectively. When we use charged lepton masses as additional input values, we can successfully obtain predictions for quark masses and Cabibbo–Kobayashi–Maskawa mixing. Since we have only one complex parameter [Formula: see text] for each mass matrix [Formula: see text], we can obtain a parameter-independent mass relation by using three equations for [Formula: see text], [Formula: see text] and [Formula: see text], where [Formula: see text] ([Formula: see text]). In this paper, we investigate the parameter-independent feature of the quark mass relation in the model.

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