THE FERMION MASSES IN E6

1998 ◽  
Vol 13 (09) ◽  
pp. 685-693
Author(s):  
H. AKCAY
Keyword(s):  
Mass Spectrum ◽  
Grand Unification ◽  
Neutrino Masses ◽  
Yukawa Couplings ◽  
Neutrino Spectrum ◽  
Fermion Masses ◽  
The Masses

We investigate a particular breaking chain of the grand unification group E6. With two smallest Higgs multiplets that have Yukawa couplings to fermions, we obtain a reasonable mass spectrum for fermions. The neutrino masses are expressed in terms of the masses of the charged fermions, leading to a predictive neutrino spectrum.

scholarly journals Fermion mass hierarchies from supersymmetric gauged flavour symmetry in 5D

2021 ◽  
Vol 10 (6) ◽  
Author(s):  
Ketan Patel
Keyword(s):  
Vacuum Expectation ◽  
Vacuum Expectation Value ◽  
Fermion Mass ◽  
Order Unity ◽  
Anomaly Cancellation ◽  
Fundamental Parameters ◽  
Yukawa Couplings ◽  
Fifth Dimension ◽  
Fermion Masses ◽  
The Masses

A mechanism to generate realistic fermion mass hierarchies based on supersymmetric gauged U(1)_FU(1)F symmetry in flat five-dimensional (5D) spacetime is proposed. The fifth dimension is compactified on S^1/Z_2S1/Z2 orbifold. The standard model fermions charged under the extra abelian symmetry along with their superpartners live in the 5D bulk. Bulk masses of fermions are generated by the vacuum expectation value of N=2N=2 superpartner of U(1)_FU(1)F gauge field, and they are proportional to U(1)_FU(1)F charges of respective fermions. This decides localization of fermions in the extra dimension, which in turn gives rise to exponentially suppressed Yukawa couplings in the effective 4D theory. Anomaly cancellation puts stringent constraints on the allowed U(1)_FU(1)F charges which leads to correlations between the masses of quarks and leptons. We perform an extensive numerical scan and obtain several solutions for anomaly-free U(1)_FU(1)F, which describe the observed pattern of fermion masses and mixing with all the fundamental parameters of order unity. It is found that the possible existence of SM singlet neutrinos substantially improves the spectrum of solutions by offering more freedom in choosing U(1)_FU(1)F charges. The model predicts Z^\primeZ′ boson mediating flavour violating interactions in both the quark and lepton sectors with the couplings which can be explicitly determined from the Yukawa couplings.

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].

NEUTRINO SPECTRUM IN NONSUPERSYMMETRIC SO(10)

1996 ◽  
Vol 11 (36) ◽  
pp. 2837-2848
Author(s):  
GABRIELA BARENBOIM
Keyword(s):  
Higgs Sector ◽  
Fine Tuning ◽  
Hierarchy Problem ◽  
Yukawa Couplings ◽  
Neutrino Spectrum ◽  
Fermion Masses ◽  
Mass Matrices

We present a predictive scheme for fermion masses and mixings inspired by nonsupersymmetric SO(10) in which the hierarchy problem is resolved without fine tuning the Yukawa couplings. This calls for a nonminimal Higgs sector which we exploit in deriving the expressions for the mass matrices. To keep the predictivity of the model under control we limit the structure of the mass matrices by imposing U(1) symmetries. A very predictive neutrino spectrum is then obtained.

scholarly journals Leptogenesis, fermion masses and mixings in a SUSY SU(5) GUT with D4 flavor symmetry

2021 ◽  
Vol 2021 (11) ◽  
Author(s):  
M. Miskaoui ◽  
M. A. Loualidi
Keyword(s):  
Numerical Study ◽  
Double Beta Decay ◽  
Neutrino Masses ◽  
Flavor Symmetry ◽  
Type I ◽  
Yukawa Couplings ◽  
Neutrino Sector ◽  
Fermion Masses ◽  
Predicted Values ◽  
Charged Leptons

Abstract We propose a model of fermion masses and mixings based on SU(5) grand unified theory (GUT) and a D4 flavor symmetry. This is a highly predictive 4D SU(5) GUT with a flavor symmetry that does not contain a triplet irreducible representation. The Yukawa matrices of quarks and charged leptons are obtained after integrating out heavy messenger fields from renormalizable superpotentials while neutrino masses are originated from the type I seesaw mechanism. The group theoretical factors from 24- and 45-dimensional Higgs fields lead to ratios between the Yukawa couplings in agreement with data, while the dangerous proton decay operators are highly suppressed. By performing a numerical fit, we find that the model captures accurately the mixing angles, the Yukawa couplings and the CP phase of the quark sector at the GUT scale. The neutrino masses are generated at the leading order with the prediction of trimaximal mixing while an additional effective operator is required to account for the baryon asymmetry of the universe (BAU). The model is remarkably predictive because only the normal neutrino mass ordering and the lower octant of the atmospheric angle are allowed while the CP conserving values of the Dirac neutrino phase δCP are excluded. Moreover, the predicted values of the effective Majorana mass mββ can be tested at future neutrinoless double beta decay experiments. An analytical and a numerical study of the BAU via the leptogenesis mechanism is performed. We focused on the regions of parameter space where leptogenesis from the lightest right-handed neutrino is successfully realized. Strong correlations between the parameters of the neutrino sector and the observed BAU are obtained.

scholarly journals The singly-charged scalar singlet as the origin of neutrino masses

2021 ◽  
Vol 2021 (5) ◽  
Author(s):  
Tobias Felkl ◽  
Juan Herrero-García ◽  
Michael A. Schmidt
Keyword(s):  
Mass Matrix ◽  
Boson Mass ◽  
Neutrino Masses ◽  
Charged Scalar ◽  
Yukawa Couplings ◽  
Left Handed ◽  
Flavour Violation ◽  
Singly Charged ◽  
Charged Lepton Sector ◽  
Scalar Singlet

Abstract We consider the generation of neutrino masses via a singly-charged scalar singlet. Under general assumptions we identify two distinct structures for the neutrino mass matrix. This yields a constraint for the antisymmetric Yukawa coupling of the singly-charged scalar singlet to two left-handed lepton doublets, irrespective of how the breaking of lepton-number conservation is achieved. The constraint disfavours large hierarchies among the Yukawa couplings. We study the implications for the phenomenology of lepton-flavour universality, measurements of the W-boson mass, flavour violation in the charged-lepton sector and decays of the singly-charged scalar singlet. We also discuss the parameter space that can address the Cabibbo Angle Anomaly.

OVERVIEW OF SUSY GUT MODELS OF NEUTRINO MIXING

2003 ◽  
Vol 18 (22) ◽  
pp. 3971-3979 ◽  
Author(s):  
S.M. BARR
Keyword(s):  
Grand Unification ◽  
Neutrino Masses ◽  
Neutrino Mixing ◽  
Neutrino Masses And Mixings

A brief review is given of some ideas for explaining neutrino masses and mixings within the context of supersymmetric grand unification. Emphasis is put on so-called lopsided models.

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.

GAUGE BOSON MASSES FROM FERMION MASSES?

1992 ◽  
Vol 07 (22) ◽  
pp. 1991-1996 ◽  
Author(s):  
R. FOOT ◽  
S. TITARD
Keyword(s):  
Gauge Boson ◽  
Z Boson ◽  
Heavy Fermions ◽  
Mass Matrix ◽  
Gauge Bosons ◽  
Fermion Masses ◽  
The Masses

We examine the possibility that the masses of the W and Z gauge bosons are induced radiatively from the masses of heavy fermions. From experiment we know that [Formula: see text][Formula: see text]. We point out that this relation can be naturally obtained if the W and Z boson masses are radiatively generated from heavy fermions which arise from a mass matrix which has large electroweak violating masses as well as very large electroweak invariant masses. Two examples of this are considered: The usual see-saw neutrino model and the SU(5)c/quark-lepton symmetric models.

scholarly journals THE PROBLEM OF NEUTRINO MASSES IN EXTENSIONS OF THE STANDARD MODEL

2001 ◽  
Vol 16 (32) ◽  
pp. 5101-5199 ◽  
Author(s):  
ISABELLA MASINA
Keyword(s):  
Proton Decay ◽  
Fine Tuning ◽  
Neutrino Masses ◽  
Flavor Symmetry ◽  
Mixing Angle ◽  
Grand Unified Theories ◽  
Triplet Splitting ◽  
Fermion Masses ◽  
The Standard Model ◽  
Neutrino Masses And Mixings

We review the problem of neutrino masses and mixings in the context of grand unified theories. After a brief summary of the present experimental status of neutrino physics, we describe how the see-saw mechanism can automatically account for the large atmospheric mixing angle. We provide two specific examples where this possibility is realized by means of a flavor symmetry. We then review in some detail the various severe problems which plague minimal GUT models (like the doublet–triplet splitting and proton-decay) and which force us to investigate the possibility of constructing more elaborate but realistic models. We then show an example of a quasirealistic SUSY SU(5) model which, by exploiting the crucial presence of an Abelian flavor symmetry, does not require any fine-tuning and predicts a satisfactory phenomenology with respect to coupling unification, fermion masses and mixings and bounds from proton decay.

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