scholarly journals Limits on the number of flavours in grand unified theories from higher-order corrections to fermion masses

1979 ◽  
Vol 157 (2) ◽  
pp. 273-284 ◽  
Author(s):  
D.V. Nanopoulos ◽  
D.A. Ross
Keyword(s):  
Higher Order ◽  
Grand Unified Theories ◽  
Fermion Masses ◽  
Unified Theories ◽  
Higher Order Corrections

scholarly journals A NEW ANSATZ FOR QUARK AND LEPTON MASS MATRICES

1992 ◽  
Vol 07 (26) ◽  
pp. 2429-2435 ◽  
Author(s):  
GIAN F. GIUDICE
Keyword(s):  
Vacuum Expectation ◽  
Cabibbo Angle ◽  
Expectation Values ◽  
Higgs Vacuum ◽  
Grand Unified Theories ◽  
Fermion Masses ◽  
Mass Matrices ◽  
Unified Theories ◽  
Free Parameters ◽  
Good Agreement

A new ansatz for quark and lepton mass matrices is proposed in the context of supersymmetric grand unified theories. The 13 parameters describing fermion masses and mixings are determined in terms of only 6 free parameters, allowing 7 testable predictions. The values of Vus, Vcb, Vub, mu, md, ms and mb are then predicted as a function of the 3 charged lepton masses, mc, mt and tan β, the ratio of Higgs vacuum expectation values. In particular the Cabibbo angle and ms/md are determined in terms of only lepton masses. All predictions are in very good agreement with experiments.

scholarly journals Employing nucleon decay as a fingerprint of SUSY GUT models using SusyTCProton

2021 ◽  
Vol 2021 (6) ◽  
Author(s):  
Stefan Antusch ◽  
Christian Hohl ◽  
Vasja Susič
Keyword(s):  
Software Tool ◽  
Decay Rates ◽  
Low Energy ◽  
Nucleon Decay ◽  
Mixing Parameters ◽  
Grand Unified Theories ◽  
Fermion Masses ◽  
Unified Theories ◽  
Rich Information ◽  
Gut Scale

Abstract While the observation of nucleon decay would be a smoking gun of Grand Unified Theories (GUTs) in general, the ratios between the decay rates of the various channels carry rich information about the specific GUT model realization. To investigate this fingerprint of GUT models in the context of supersymmetric (SUSY) GUTs, we present the software tool SusyTCProton, which is an extension of the module SusyTC to be used with the REAP package. It allows to calculate nucleon decay rates from the relevant dimension five GUT operators specified at the GUT scale, including the full loop-dressing at the SUSY scale. As an application, we investigate the fingerprints of two example GUT toy models with different flavor structures, performing an MCMC analysis to include the experimental uncertainties for the charged fermion masses and CKM mixing parameters. While both toy models provide equally good fits to the low energy data, we show how they could be distinguished via their predictions of ratios for nucleon decay rates. Together with SusyTCProton we also make the additional module ProtonDecay public. It can be used independently from REAP and allows to calculate nucleon decay rates from given D = 5 and D = 6 operator coefficients (accepting the required SUSY input for the D = 5 case in SLHA format). The D = 6 functionality can also be used to calculate nucleon decay in non-SUSY GUTs.

scholarly journals New model for fermion masses in supersymmetric grand unified theories

1994 ◽  
Vol 49 (9) ◽  
pp. 4962-4965 ◽  
Author(s):  
Alexander Kusenko ◽  
Robert Shrock
Keyword(s):  
New Model ◽  
Grand Unified Theories ◽  
Fermion Masses ◽  
Unified Theories

scholarly journals Fermion masses and mixings in grand unified theories with noncanonicalU(1)Y

2008 ◽  
Vol 78 (1) ◽  
Author(s):  
Ilia Gogoladze ◽  
Chin-Aik Lee ◽  
Tianjun Li ◽  
Qaisar Shafi
Keyword(s):  
Grand Unified Theories ◽  
Fermion Masses ◽  
Unified Theories

Water, Water, Here and There

2018 ◽  
Author(s):  
Steven E. Vigdor
Keyword(s):  
Quark Mass ◽  
Mass Difference ◽  
Baryon Number ◽  
Electroweak Phase Transition ◽  
Hydrogen Burning ◽  
Quark Masses ◽  
Grand Unified Theories ◽  
Down Quark ◽  
Unified Theories ◽  
The Stability

Chapter 4 deals with the stability of the proton, hence of hydrogen, and how to reconcile that stability with the baryon number nonconservation (or baryon conservation) needed to establish a matter–antimatter imbalance in the infant universe. Sakharov’s three conditions for establishing a matter–antimatter imbalance are presented. Grand unified theories and experimental searches for proton decay are described. The concept of spontaneous symmetry breaking is introduced in describing the electroweak phase transition in the infant universe. That transition is treated as the potential site for introducing the imbalance between quarks and antiquarks, via either baryogenesis or leptogenesis models. The up–down quark mass difference is presented as essential for providing the stability of hydrogen and of the deuteron, which serves as a crucial stepping stone in stellar hydrogen-burning reactions that generate the energy and elements needed for life. Constraints on quark masses from lattice QCD calculations and violations of chiral symmetry are discussed.

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