A possible mechanism to derive light fermion masses from a large mass scale

1982 ◽  
Vol 34 (11) ◽  
pp. 318-322 ◽  
Author(s):  
T. Kobayashi
Keyword(s):  
Large Mass ◽  
Mass Scale ◽  
Fermion Masses ◽  
Light Fermion

scholarly journals Dark moments for the Standard Model?

2021 ◽  
Vol 2021 (11) ◽  
Author(s):  
Thomas G. Rizzo
Keyword(s):  
Standard Model ◽  
Magnetic Dipole ◽  
Parameter Space ◽  
Gauge Coupling ◽  
Large Mass ◽  
Mass Scale ◽  
Complex Scalar ◽  
Quantum Numbers ◽  
The Standard Model ◽  
Model Setup

Abstract If dark matter (DM) interacts with the Standard Model (SM) via the kinetic mixing (KM) portal, it necessitates the existence of portal matter (PM) particles which carry both dark and SM quantum numbers that will appear in vacuum polarization-like loop graphs. In addition to the familiar ∼ eϵQ strength, QED-like interaction for the dark photon (DP), in some setups different loop graphs of these PM states can also induce other coupling structures for the SM fermions that may come to dominate in at least some regions of parameter space regions and which can take the form of ‘dark’ moments, e.g., magnetic dipole-type interactions in the IR, associated with a large mass scale, Λ. In this paper, motivated by a simple toy model, we perform a phenomenological investigation of a possible loop-induced dark magnetic dipole moment for SM fermions, in particular, for the electron. We show that at the phenomenological level such a scenario can not only be made compatible with existing experimental constraints for a significant range of correlated values for Λ and the dark U(1)D gauge coupling, gD, but can also lead to quantitatively different signatures once the DP is discovered. In this setup, assuming complex scalar DM to satisfy CMB constraints, parameter space regions where the DP decays invisibly are found to be somewhat preferred if PM mass limits from direct searches at the LHC and our toy model setup are all taken seriously. High precision searches for, or measurements of, the e+e− → γ + DP process at Belle II are shown to provide some of the strongest future constraints on this scenario.

scholarly journals FLAVOR VIOLATION IN A MINIMAL SO(10)×A4 SUSY GUT

2012 ◽  
Vol 27 (01) ◽  
pp. 1250005 ◽  
Author(s):  
ABDELHAMID ALBAID
Keyword(s):  
Neutral Current ◽  
Branching Ratio ◽  
Flavor Violation ◽  
Flavor Changing ◽  
Fermion Masses ◽  
Fermion Fields ◽  
Experimental Constraint ◽  
Flavor Changing Neutral Current ◽  
High Degree ◽  
Light Fermion

Flavor violating processes in the quark and lepton sectors are investigated within a realistic supersymmetric SO(10)×A4 grand unification model. By employing exotic heavy fermion fields, this model successfully describes various features of the fermion masses and mixings including large neutrino mixings accompanied by small quark mixings. In this model the flavor violation is induced at GUT scale, at which A4 flavor symmetry is broken, as a consequence of the large mixings of the light fermion fields with these exotic heavy fields. The stringent experimental constraint from μ→eγ decay rate necessitates a high degree of degeneracy of the supersymmetry breaking soft scalar masses of the exotic heavy fields and supersymmetric scalar partners of the light fermion fields. The choice of slepton masses of order 1 TeV is found to be consistent with the constraints from branching ratio of μ→eγ and with all other flavor changing neutral current processes being sufficiently suppressed.

LIGHT FERMION MASSES FROM SU(3)color×U(1)e.m.?

1989 ◽  
Vol 04 (12) ◽  
pp. 1159-1167
Author(s):  
A. DAVIDSON ◽  
B. MARGOLIS ◽  
J. ROBINSON ◽  
P. VALIN
Keyword(s):  
Cp Violation ◽  
Mass Formula ◽  
First Generation ◽  
Complete Model ◽  
Seesaw Mechanism ◽  
Fermion Masses ◽  
Type Mass ◽  
Light Fermion

We consider the hypothesis that (i) mv≃0 because the neutrino is SU (3)c× U (1) e.m. neutral, (ii) m electron = 0 at the isospin limit where mu=md, and (iii) all first-generation fer-mions turn massless as αc, α e.m. →0. This hypothesis is supported by the empirical Abraham-Lorentz-type mass formula m=(ζ1Q+ζ2B)2, whose quadratic structure is attributed to a universal seesaw mechanism. We demonstrate how such a formula can stay exact even when switching on the inter-generational mixings. We present a complete model with the above features which gives quark and lepton masses and the K-M matrix, including CP violation.

scholarly journals Gauge U(1) dark symmetry and radiative light fermion masses

2016 ◽  
Vol 760 ◽  
pp. 59-62 ◽  
Author(s):  
Corey Kownacki ◽  
Ernest Ma
Keyword(s):  
Fermion Masses ◽  
Light Fermion

scholarly journals FERMION MASSES, NEUTRINO MIXING AND CP VIOLATION FROM THE ANTI-GRAND-UNIFICATION MODEL

1998 ◽  
Vol 13 (29) ◽  
pp. 5037-5074 ◽  
Author(s):  
C. D. FROGGATT ◽  
M. GIBSON ◽  
H. B. NIELSEN ◽  
D. J. SMITH
Keyword(s):  
Cp Violation ◽  
Mass Scale ◽  
Grand Unification ◽  
Neutrino Mixing ◽  
Mixing Angles ◽  
Quantum Numbers ◽  
Fermion Masses ◽  
The Standard Model ◽  
Higgs Fields ◽  
Fundamental Mass

The fermion masses and mixing angles are fitted using only three free parameters in a nonsupersymmetric extension of the Standard Model, with new, approximately conserved chiral gauge quantum numbers broken by a set of Higgs fields. The fundamental mass scale of this anti-grand-unification model is given by the Planck mass. We also calculate neutrino mixing angles and masses, as well as CP violation from the CKM matrix. A good fit to the observed fermion masses is obtained, but our predictions of the neutrino masses are too small to lead to any observable neutrino oscillation effects claimed today, without introducing another mass scale. We also give some arguments in support of this type of model based on the observed fermion masses.

scholarly journals Large Mass Scale by Strong Gauge Dynamics with Infrared Fixed Point

2005 ◽  
Vol 113 (2) ◽  
pp. 413-427 ◽  
Author(s):  
T. Kobayashi ◽  
H. Nakano ◽  
H. Terao ◽  
Y. Yamada
Keyword(s):  
Fixed Point ◽  
Large Mass ◽  
Mass Scale

scholarly journals A genuine fermionic quintuplet seesaw model: phenomenological introduction

2021 ◽  
Vol 2021 (6) ◽  
Author(s):  
Saiyad Ashanujjaman ◽  
Kirtiman Ghosh
Keyword(s):  
Center Of Mass ◽  
Majorana Neutrino ◽  
Mass Scale ◽  
Tree Level ◽  
Center Of Mass Energy ◽  
Fermion Masses ◽  
Mass Dimension ◽  
The Masses ◽  
Displaced Vertex ◽  
Lepton Flavour

Abstract We study a model which generates Majorana neutrino masses at tree-level via low-energy effective operator with mass-dimension-9. Introduction of such a higher dimensional operator brings down the lepton number violating mass scale to TeV making such model potentially testable at present or near future colliders. This model possesses several new SU(2)L fermionic multiplets, in particular, three generations of triplets, quadruplets and quintuplets, and thus a rich phenomenology at the LHC. Noting that lepton flavour violation arises very naturally in such setup, we put constraints on the Yukawa couplings and heavy fermion masses using the current experimental bounds on lepton flavour violating processes. We also obtain 95% CL lower bounds on the masses of the triplets, quadruplets and quintuplets using a recent CMS search for multilepton final states with 137 inverse femtobarn integrated luminosity data at 13 TeV center of mass energy. The possibility that the heavy fermions could be long-lived leaving disappearing charge track signatures or displaced vertex at the future colliders like LHeC, FCC-he, MATHUSLA, etc. is also discussed.

scholarly journals PROTON DECAY, FERMION MASSES AND TEXTURE FROM EXTRA DIMENSIONS IN SUSY GUT's

2004 ◽  
Vol 19 (11) ◽  
pp. 1715-1736 ◽  
Author(s):  
MITSURU KAKIZAKI ◽  
MASAHIRO YAMAGUCHI
Keyword(s):  
Extra Dimension ◽  
Mass Matrix ◽  
Spatial Dimension ◽  
Proton Decay ◽  
Mass Scale ◽  
Wave Functions ◽  
Fermion Mass ◽  
Quark Masses ◽  
Fermion Masses ◽  
The Hierarchical Structure

In supersymmetry, there are gauge invariant dimension 5 proton decay operators which must be suppressed by a mass scale much larger than the Planck mass. It is natural to expect that this suppression should be explained by a mechanism that explains the hierarchical structure of the fermion mass matrices. We apply this argument to the case where wave functions of chiral multiplets are localized under a kink background along an extra spatial dimension and the Yukawa couplings as well as the coefficients of the proton decay operators are determined by the overlap of the relevant wave functions. A configuration is found in the context of SU(5) supersymmetric grand unified theory that yields realistic values of quark masses, mixing angles, CP phase and charged lepton masses and sufficiently small genuine dimension 5 proton decay operators. Inclusion of SU(5) breaking effects is essential in order to obtain non-vanishing CP phase as well as correct lepton masses. The resulting mass matrix has a texture structure in which texture zeros are a consequence of extremely small overlap of the wave functions. Our approach requires explicit breaking of supersymmetry in the extra dimension, which can be realized in (de)constructing extra dimension.

Sign in / Sign up

Export Citation Format

Share Document