Related papers: Partially flavour non-universal $U(1)$ and radiati…
An effective theory is proposed, combining the standard gauge group $SU(3)_{C}\otimes SU(2)_{L}\otimes U(1)_{Y}$ with a horizontal discrete symmetry. By assigning appropriate charges under this discrete symmetry to the various fermion…
Naturally small neutrino masses can arise in some grand unified models. The mechanism of neutrino mass generation in these models typically requires the existence of neutral heavy leptons. We study the low-energy phenomenology of these new…
In this work we present the results of a numerical investigation of SU(2) gauge theory with N_f = 3/2 flavours of fermions, corresponding to 3 Majorana fermions, which transform in the adjoint representation of the gauge group. At two…
A possible minimal model of the gauge-Higgs unification based on the higher dimensional spacetime M^4 X (S^1/Z_2) and the bulk gauge symmetry SU(3)_C X SU(3)_W X U(1)_X is constructed in some details. We argue that the Weinberg angle and…
Motivated by the growing evidence for the possible lepton flavour universality violation after the first results from Fermilab's muon $(g-2)$ measurement, we revisit one of the most widely studied anomaly free extensions of the standard…
We consider non-universal 'minimal' Z' models, whose additional U(1) charge is a non-anomalous linear combination of the weak hypercharge Y, the baryon number B and the partial lepton numbers (L_e, L_mu, L_tau), with no exotic fermions…
After we study the 6-dimensional ${\cal N} = (1, 1)$ supersymmetry breaking and $R$ symmetry breaking on $M^4\times T^2/Z_n$, we construct two ${\cal N} = (1, 1)$ supersymmetric $E_6$ models on $M^4\times T^2/Z_3$ where $E_6$ is broken down…
We argue in favor of dynamical mass generation in an SU(2)xU(1) electroweak model with two complex scalar doublets with ordinary masses. The masses of leptons and quarks are generated by ultraviolet-finite non-perturbative solutions of the…
The latest measurements of the anomalous muon magnetic moment $a^{}_\mu \equiv (g^{}_\mu - 2)/2$ show a $4.2\sigma$ discrepancy between the theoretical prediction of the Standard Model and the experimental observations. In order to account…
We study a model with $U(1)$ gauged lepton number symmetry in which the active neutrino masses are generated at two-loop level through the spontaneous breaking of the lepton number symmetry. To cancel gauge anomalies some exotic leptons are…
By invoking the existence of a general custodial O(2) symmetry, a minimal Left-Right symmetric model based on the gauge group G=SU(2)L SU(2)R U(1)BL is shown to require the existence of only two physical Higgs bosons. The lighter Higgs is…
A new model for tiny neutrino masses is proposed in the gauge theory of $SU(3)_C \otimes SU(3)_L \otimes U(1)_X$, where neutrino masses are generated via the quantum effect of new particles. In this model, the fermion content is taken to be…
We present a renormalizable fermion mass model based on the symmetry $Q_4$ that accommodates all fermion masses and mixing angles in both the quark and lepton sectors. It requires the presence of only four SU(2) doublet scalar fields…
Degenerate neutrino masses are excluded by experiment. The experimentally measured mass squared differences together with the yet undetermined absolute neutrino mass scale allow for a quasi-degenerate mass spectrum. For the lightest…
The Standard Model is extended minimally with a new flavor-violating family symmetry ${\rm U(1)}_\lambda$, which acts only on leptons including the right-handed neutrinos. The model is anomaly free with family-dependent ${\rm U(1)}_\lambda$…
We construct anomaly-free $U(1)_1\times U(1)_2\times...\times U(1)_m$ gauge extensions of the Standard Model. To perform this construction we put together anomaly-free $U(1)$ extensions of one and two families of fermions. The availability…
We propose a simple $U(2)$ model of flavor compatible with an $SU(5)$ GUT structure. All hierarchies in fermion masses and mixings arise from powers of two small parameters that control the $U(2)$ breaking. In contrast to previous $U(2)$…
We propose a model based on the $SU(5)$ grand unification with an extra $A_{4}\otimes Z_{2}\otimes Z_{2}^{\prime }\otimes Z_{2}^{\prime \prime}\otimes U\left( 1\right) _{f}$ flavor symmetry, which accounts for the pattern of the SM fermion…
We propose a supersymmetric extension of the anomaly-free and three families nonuniversal $U(1)$ model, with the inclusion of four Higgs doublets and four Higgs singlets. The quark sector is extended by adding three exotic quark singlets,…
Neutrino masses and mixings have important implications for models of fermion masses, and, most directly, for the charged lepton sector. We consider supersymmetric Abelian flavor models, where neutrino mass parameters are related to those…