Related papers: Unification and Fermion Mass Structure
In realistic grand unified models there are typically extra vectorlike matter multiplets at the GUT scale that are needed to explain the family hierarchy. These contain neutrinos that, when integrated out, can modify the usual neutrino…
Since $\mathrm{SO}(10)$ GUTs unify all fermions of the Standard Model plus a right-chiral neutrino in a representation $\mathbf{16}$ per family, they have the potential to be maximally predictive regarding the ratios between the masses (or…
The importance of the mass spectroscopy of the superparticles is emphasized. It will be shown that the gauge coupling constants give us information on the GUT-scale mass spectrum once the superparticle masses are known. The gaugino masses…
We review and compare theoretically and phenomenologically a number of possible family symmetries, which when combined with unification, could be important in explaining quark, lepton and neutrino masses and mixings, providing new results…
We discuss various aspects of the early petite unification (PUT) of quarks and leptons based on the gauge group G_PUT=SU(4)_PS x SU(2)_L x SU(2)_R x SU(2)_H. This unification takes place at the scale M= O(1-2 TeV) and gives the correct…
we study fermion masses and flavor mixing in a supersymmetric SO(10) model, where $\mathbf{10}$, $\mathbf{120}$ and $\mathbf{\bar{126}}$ Higgs multiplets have Yukawa couplings with matter multiplets and give masses to quarks and leptons…
The idea of quark-lepton universality at high energies has recently been explored in unified theories based upon the quartification gauge group SU(3)^4. These schemes encompass a quark-lepton exchange symmetry that results upon the…
The first fermion family might play a key role in understanding the structure of flavour: a role of the mass unification point. The GUT scale running masses $\bar{m}_{e,u,d}$ are rather close, which may indicate an approximate symmetry…
We propose a new mass matrix ansatz: At the grand unified (GU) scale, the standard model (SM) Yukawa coupling matrix elements are integer powers of the square root of the GU gauge coupling constant \varepsilon \equiv…
The fermion mass problem is briefly reviewed. The observed hierarchy of quark and charged lepton masses strongly suggests the existence of an approximately conserved chiral flavour symmetry beyond the Standard Model. It is argued that in…
We present an extension of the Standard Model (SM) without supersymmetry, which we use to calculate order of magnitude values for the elements of the mass matrices in the SM. In our model we can fit the 9 quark and lepton masses and 3…
Different approaches to the fermion mass problem are reviewed. We illustrate these approaches by summarizing recent developments in models of quark and lepton mass matrices. Dynamical calculations of the top quark mass are discussed, based…
We construct a model in which the hierarchies of the quark and lepton masses and mixing are explained by the $\Gamma_6^\prime$ modular flavor symmetry. The hierarchies are realized by the Froggatt-Nielsen-like mechanism due to the residual…
The idea of quark-lepton universality at high energies has been introduced as a natural extension to the standard model. This is achieved by endowing leptons with new degrees of freedom -- leptonic colour, an analogue of the familiar quark…
Different approaches to the quark-lepton mass problem are reviewed. The infrared quasifixed point predictions for the top quark mass are discussed for the Standard Model and its minimal supersymmetric extension, with particular reference to…
In N = 1 super Yang-Mills theories, under certain conditions satisfied by the spectrum and the Yukawa couplings, the beta functions will vanish to all orders in perturbation theory. We address the generation of realistic quark mixing angles…
In this talk, we introduce a new scenario of grand unified theory (GUT) with anomalous $U(1)_A$ gauge symmetry, which can explain doublet-triplet splitting, quark and lepton masses and mixing angles. In neutrino sector, the scenario…
We suggest a simple grand unified theory where the fifth dimensional coordinate is compactified on an $S_1/(Z_2 \times Z_2')$ orbifold. This model is based on the supersymmetric flipped $SU(5) \times U(1)$ grand unified theory, which can…
In orbifold models, gauge, Higgs and the matter fields can be unified in one multiplet from the compactification of higher dimensional supersymmetric gauge theory. We study how three families of chiral fermions can be unified in the gauge…
We analyze some consequences of grand unification of the third-generation Yukawa couplings, in the context of the minimal supersymmetric standard model. We address two issues: the prediction of the top quark mass, and the generation of the…