Related papers: Running quark and lepton parameters at various sca…
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…
The unification of gauge and Yukawa couplings within the minimal supersymmetric standard model is studied at the two loop level. We derive an expression for the effective scale, $T_{SUSY}$, which characterizes the supersymmetric particle…
It is well-known that the $SU(5)$ grand unified theory, with the standard model quarks and leptons unified in $\overline{5}$ and $10$ and the electroweak Higgs doublet residing in $5$ dimensional representations, leads to relation,…
Grand Unified Theories (GUTs) can feature predictions for the ratios of quark and lepton Yukawa couplings at high energy, which can be tested with the increasingly precise results for the fermion masses, given at low energies. To perform…
We consider an extension of the Georgi-Glashow SU(5) GUT model by a 45-dimensional scalar and a 24-dimensional fermionic representation, where the latter leads to the generation of the observed light neutrino masses via a combination of a…
The observed hierarchy of quark and lepton masses and mixings may be obtained by adding an abelian family symmetry to the Minimal Supersymmetric Model and coupling quarks and leptons to an electroweak singlet scalar field. In a large class…
We discuss the unification of the bottom quark and tau lepton Yukawa couplings within the framework of the next-to-minimal supersymmetric standard model. We compare the allowed regions of the $m_t$-$\tan \beta$ plane to those in the minimal…
We calculate quark and lepton masses and quark mixing angles in the framework of a supersymmetric SU(4)$\otimes$SU(2)$_L\otimes$SU(2)$_R$ model where the gauge group is broken at 10$^{16}$ GeV. The model predicts third family top-bottom-tau…
We perform a detailed study of the renormalization group equations in the inverse seesaw model. Especially, we derive compact analytical formulas for the running of the neutrino parameters in the standard model and the minimal…
Supersymmetric Grand Unification usually provides unification of the bottom quark and the tau lepton Yukawa couplings at the GUT scale. In the CMSSM this can be realised only for a very particular choice of parameters. In this letter we…
Masses of heavy Standard Model fermions (top-quark, bottom-quark, and tau-lepton) play an important role in the analysis of theories beyond the SM. They serve as low-energy input and reduce the parameter space of such theories. In this…
We analyze the implications of the light gluino scenario for the unification of gauge and Yukawa couplings within the minimal supersymmetric standard model. Within this scheme all fermionic supersymmetric particles are naturally light,…
I analyze the predictions for the strong gauge coupling, $\alpha_3(M_Z) $, and the top quark and light Higgs masses in the framework of gauge and bottom-tau Yukawa coupling unification in the minimal supersymmetric standard model. These…
We investigate a model that the Yukawa coupling form is constructed by two kinds of matrix (M_0 and M_1). For example, in the SO(10) GUT model, M_0 and M_1 are Yukawa couplings generated by the 10 and 126 Higgs scalars. We study how this…
We make a systematic theoretical analysis of the masses and their variation with energy by solving the renormalization group equation (RGE) in the Minimal Supersymmetric Standard Model (MSSM). The unification fermion masses of around 115…
Relations among fermion masses and mixing angles at the scale of grand unification are modified at lower energies by renormalization group running induced by gauge and Yukawa couplings. In supersymmetric theories, the $b$ quark and $\tau$…
Fermion masses and mixing angles are studied in an SUSY $SO(10)\times \Delta (48)\times U(1)$ model with small $\tan\beta$. Thirteen parameters involving masses and mixing angles in the quark and charged lepton sector are successfully…
We calculate threshold corrections to the running gauge and Yukawa couplings in the Exceptional Supersymmetric Standard Model (E6SSM) and analyse the more precise and reliable mass spectra in a constrained model (CE6SSM). Full expressions…
A new ansatz of democratic lepton mixing is proposed at the GUT scale and the radiative corrections to its phenomenological consequences are calculated at the electroweak scale. We demonstrate that it is possible to obtain the…
The one-loop evolution of Yukawa couplings in the minimal supersymmetric left-right model (MSUSYLR) model with a wide variation of the right handed breaking scale $M_R$ from 1 TeV to $10^{18}$ GeV is studied assuming that all third…