Related papers: The discrete family symmetry as a possible solutio…
It is shown that realistic models can be constructed in which the Standard Model Higgs field is in a non-trivial multiplet of a non-abelian family group of the quarks and leptons. It is shown that the observed quark and lepton masses and…
We address the question, how general is the gauge sector in extra-dimensional models which explain hierarchies of masses and mixings of quarks, charged leptons and neutrinos in terms of a single family of multidimensional fermions. We give…
The flavour puzzle remains as one of the most intriguing enigmas of particle physics. In this thesis, we propose and study theories of flavour which generically hint to a multi-scale origin of flavour. First we explore the idea of…
The heaviness of the third family fermions and the experimental absence of large flavor violating processes suggest, in supersymmetric theories, that the three families belong to a $2+1$ representation of a horizontal symmetry $G_H$. In…
While solving the supersymmetric flavour problem, a U(2) flavour symmetry might be at the origin of the pattern of fermion masses and mixings. The consequences of this hypothesis are spelled out concerning the parameters of the CKM matrix…
The problem of quark-lepton families is discussed in the "bottom-up" phenomenological approach to the extensions of the Standard model. It provides the possibility of the {\it Horizontal unification} of the three known families on the basis…
We discuss the possibility of obtaining a non-abelian discrete flavor symmetry from an underlying continuous, possibly gauged, flavor symmetry SU(2) or SU(3) through spontaneous symmetry breaking. We consider all possible cases, where the…
We present a family-non-universal extension of the Standard Model where the the first two families feature both quark-lepton and electroweak-flavour unification, via the $SU(4) \times Sp(4)_L \times Sp(4)_R$ gauge group, whereas…
We study $b \to s \ell_1^+ \ell_2^-$ transitions, both for the lepton flavour conserving $\ell_1=\ell_2$ and violating case $\ell_1 \neq \ell_2$, in a minimal extension of the Standard Model proposed in [1]. In this framework, the Standard…
We construct a supersymmetric theory of flavor based on the discrete gauge group (D_6)^2, where D_6 describes the symmetry of a regular hexagon under proper rotations in three dimensions. The representation structure of the group allows one…
We consider a class of discrete flavour symmetries for leptons based on the group S(3) and A(4) with an hybrid breaking pattern. The aim is to construct models in which the same flavon fields producing the mixing pattern are also…
We present a method to identify symmetry groups of the Yukawa sector of the three-Higgs-doublet model and to determine the implication that the symmetry has on the lepton masses and mixing. The method can accommodate different hypotheses…
Motivated by the idea of Comprehensive Unification, we consider a gauged $SO(3)$ flavor extension of the Standard Model, including right-handed neutrinos and a Peccei-Quinn symmetry. The model accommodates the observed fermion masses and…
We study the set of models in which the Standard Model symmetry is extended with the flavour group A4 and there are three copies of the Standard Model Higgs that transform as a triplet under this group. In this setup, new channels for…
We investigate an extension of the Standard Model with a partially flavour non-universal abelian gauge symmetry that enables radiative mass generation for lighter fermions. With flavour-universal charges for the first two generations,…
We propose a new model with flavor-dependent gauged $U(1)_{B-L_1}\times U(1)_{B-L_{2}-L_{3}}$ symmetry in addition to the flavor-blind one in the standard model. The model contains three right-handed neutrinos to cancel gauge anomalies and…
We present a complete, calculable, and phenomenologically viable model of dynamical supersymmetry breaking. The model is a simple extension of the so called 3-2 model, with gauge group SU(3)xSU(2)xG_SM and the MSSM fields directly coupled…
The use of nonabelian discrete groups G as family symmetries is discussed in detail. Out of all such groups up to order g = 31, the most appealing candidates are two subgroups of SU(2): the dicyclic [double dihedral] group G = $Q_6 ={…
We present a supersymmetric flavour model based on the T' discrete group, which explains fermion masses and mixings. The flavour symmetry, acting in the supersymmetric sector, provides well defined sfermion mass matrices and the resulting…
We present an extended 331 model with $T'$ discrete flavor symmetry that simultaneously explains the need to have exactly three generations and provides acceptable quark and lepton masses and mixings. New fermionic states and gauge bosons…