Fe b 20 06 Masses of Fermions in Supersymmetric Models (original) (raw)

Masses of fermions in supersymmetric models

Journal of High Energy Physics, 2006

We consider the mass generation for the usual quarks and leptons in some supersymmetric models. The masses of the top, the bottom, the charm, the tau and the muon are given at the tree level. All the other quarks and the electron get their masses at the one loop level in the Minimal Supersymmetric Standard Model (MSSM) and in two Supersymmetric Left-Right Models, one model uses triplets (SUSYLRT) to break SU (2) R-symmetry and the other use doublets(SUSYLRD).

Masses of Quarks and Leptons in a Supersymmetric GUT

The masses and their variation with energy of the elementary particles obtained by solving the one loop renormalization group equation (RGE) in the Minimal Supersymmetric Standard Model (MSSM) is considered. A mass about 115 GeV for all the fermions at GUT scale is found as the possible solution of RGE. The mass spectra of all the fermions are also obtained within acceptable errors. They are shown graphically to desend for the top quark but ascend for all other fermions from the laboratory to the GUT scale. Comment: 7 pages, one table, one figure

Reexamining the fermion mass relations in the supersymmetric SU (4) ⊗ O (4) GUT model

Physics Letters B, 1992

We study in detail the charged fermion masses in the context of the minimal GUT-version of the supersymmetric SU (4) ® O (4) model. We show how the presence of vacuum expectation values (VEVs) of the order of the GUT mass scale for the fight-handed (RH) sneutrinos may modify the "naive" equality of the charged-lepton and the down-quark masses at M6 = 1016 GeV. In particular, we indicate how one can successfully modify the problematic low-energy relation between ms and m u, while preserving the good prediction rob/mr = r ", 2.7 (r being the renormalization parameter). The fact that the VEVs of the RH sneutrinos are predicted to be of order ~ MG, may also have interesting consequences in the mechanism of symmetry breaking of the model.

Lepton masses in a supersymmetric 3-3-1 model

Physical Review D, 2002

We consider the mass generation for both charginos and neutralinos in a 3-3-1 supersymmetric model. We show that R-parity breaking interactions leave the electron and one of the neutrinos massless at the tree level. However the same interactions induce masses for these particles at the 1-loop level. Unlike the similar situation in the minimal supersymmetric standard model the masses of the neutralinos are related to the masses of the charginos.

Calculating fermion masses in superstring derived standard-like models

Nuclear Physics B, 1997

One of the intriguing achievements of the superstring derived standard-like models in the free fermionic formulation is the possible explanation of the top quark mass hierarchy and the successful prediction of the top quark mass. An important property of the superstring derived standard-like models, which enhances their predictive power, is the existence of three and only three generations in the massless spectrum. Up to some motivated assumptions with regard to the light Higgs spectrum, it is then possible to calculate the fermion masses in terms of string tree level amplitudes and some VEVs that parameterize the string vacuum. I discuss the calculation of the heavy generation masses in the superstring derived standard-like models. The top quark Yukawa coupling is obtained from a cubic level mass term while the bottom quark and tau lepton mass terms are obtained from nonrenormalizable terms. The calculation of the heavy fermion Yukawa couplings is outlined in detail in a specific toy model. The dependence of the effective bottom quark and tau lepton Yukawa couplings on the flat directions at the string scale is examined. The gauge and Yukawa couplings are extrapolated from the string unification scale to low energies. Agreement with α strong , sin 2 θ W and α em at M Z is imposed, which necessitates the existence of intermediate matter thresholds. The needed intermediate matter thresholds exist in the specific toy model. The effect of the intermediate matter thresholds on the extrapolated Yukawa couplings in studied. It is observed that the intermediate matter thresholds also help to maintain the correct b/τ mass relation. It is found that for a large portion of the parameter space, the LEP precision data for α strong , sin 2 θ W and α em , as well as the top quark mass and the b/τ mass relation can all simultaneously be consistent with the superstring derived standard-like models. Possible corrections due to the supersymmetric mass spectrum are studied as well as the minimization of the supersymmetric Higgs potential. It is demonstrated that the calculated values of the Higgs VEV ratio, tan β = v 1 /v 2 , can be compatible with the minimization of the one-loop effective Higgs potential.

Fermion masses in superstring theory

1995

We give a model-independent discussion of fermion masses in four-dimensional heterotic superstring theories. We discuss the tree level contributions and quantum corrections, including one-loop threshold effects and masses generated as a result of non-perturbative supersymmetry breaking. We also point out that superstring models give rise to a generic µ-term in the effective low energy Lagrangian. *

Symmetries and Mass Predictions of the Supersymmetric Quark Model

QCD justification of SU(m/n) supergroups are shown to provide a basis for the existence of an approximate hadronic supersymmetry. Effective Hamiltonian of the relativistic quark model is derived, leading to hadronic mass formulae in remarkable agreement with experiments. Bilocal approximation to hadronic structure and incorporation of color through octonion algebra (based on quark-antidiquark symmetry) is also shown to predict exotic diquark-antidiquark ($D-\bar{D}$) meson states. A minimal supersymmetric sceme based on SU(3)ctimesSU(6/1)SU(3)^c \times SU(6/1)SU(3)ctimesSU(6/1) that excludes exotics is constructed. Symmetries of three quark systems and possible relativistic formulation of the quark model through the spin realization of Wess-Zumino algebra is presented.