Related papers: Light Mediators in Anomaly Free $U(1)_X$ Models I …
An anomaly-free U(1) gauge extension of the standard model (SM) is presented. Only one Higgs doublet with a nonzero vacuum expectation is required as in the SM. New fermions and scalars as well as all SM particles transform nontrivially…
We identify a class of $U(1)_X$ models which can explain the $R_K$ anomaly and the neutrino mixing pattern, by using a bottom-up approach. The different $X$-charges of lepton generations account for the lepton universality violation…
An alternative left-right model of quarks and leptons, where the $SU(2)_R$ lepton doublet $(\nu,l)_R$ is replaced with $(n,l)_R$ so that $n_R$ is not the Dirac mass partner of $\nu_L$, has been known since 1987. Previous versions assumed a…
We extend the $SU(3)_c \times SU(2)_L \times U(1)_Y$ standard model by a $U(1)_{Y'}$ gauge symmetry. Three right-handed neutrinos are introduced to cancel the gauge anomaly. One Higgs singlet is responsible for spontaneously breaking the…
We construct realistic supergravity models where supersymmetry breaking arises from the $D$-terms of an anomalous $U(1)$ gauge symmetry broken at the Planck scale. The model has the attractive feature that the gaugino masses, the $A$ and…
We present a detailed analysis of how a mixed-anomaly-free U(1) symmetry can be used to both resolve the slepton mass problem associated with Anomaly Mediated Supersymmetry Breaking and generate the fermion mass hierarchy via the…
We extend the Standard Model (SM) by adding a pair of fermionic SU(2)-doublets with opposite hypercharge and a fermionic SU(2)-triplet with zero hypercharge. We impose a discrete Z_2-symmetry that distinguishes the SM fermions from the new…
We propose a predictive model based on the $SU(3)_C\times SU(3)_L\times U(1)_X$ gauge symmetry, which is supplemented by the $D_4$ family symmetry and several auxiliary cyclic symmetries whose spontaneous breaking produces the observed SM…
Several constructions motivate the existence of a dark $U(1)_D$ gauge boson which interacts with the Standard Model only through its kinetic mixing or loop induced processes. We describe two typical examples with specific signatures in…
We construct flavor-dependent chiral U(1)' models with a Z' boson which couples to the right-handed up-type quarks in the standard model (SM). To make the models have realistic renormalizable Yukawa couplings, we introduce new Higgs…
We propose a gauged two-Higgs-doublet model (2HDM) featuring an anomalous Peccei-Quinn symmetry, $U(1)_{PQ}$. Dangerous tree-level flavour-changing neutral currents, common in 2HDMs, are forbidden by the extra gauge symmetry, $U(1)_X$. In…
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…
We study a particular class of Abelian gauged Nambu-Jona-Lasinio models with global U_L(N)xU_R(N) symmetry, where N is the number of fermion flavors. We show, by treating the gauge interaction in the ladder approximation and four-fermion…
In the context of the free-fermionic formulation of the heterotic superstring, we construct a three generation N=1 supersymmetric SU(4)xSU(2)LxSU(2)R model supplemented by an SU(8) hidden gauge symmetry and five Abelian factors. The…
The Standard Model has three generations of fermions and although it does not contain any explicit reason for this, the existence of additional generations is now very constrained by experiment. Present measurements are saturating…
The weak currents with respect to the diagonal neutral bosons $Z$,$Z^{\prime}$, and $Z^{\prime\prime}$ of a specific \textbf{$SU(4)_{L}\otimes U(1)_{Y}$} gauge model are computed in detail for all the fermion families involved therein. Our…
The ${\rm U(1)}_{L_\mu - L_\tau}$ model is anomaly-free with the Standard Model (SM) fermion content, and can make substantial contributions to the muon $(g-2)$ at the level of $\Delta a_\mu \sim O(10) \times 10^{-10}$ for $M_{Z'} \sim…
We present the supersymmetric $SU(5)$ models which provide a simple ``all order'' solution to the doublet-triplet splitting problem through the missing doublet mechanism. The crucial role is played by the anomalous $U(1)_A$ gauge symmetry…
We consider a class of $U(1)^\prime$-extended MSSM in which the $U(1)^{\prime}$ symmetry is broken by vacuum expectation values (VEVs) of four MSSM singlet fields. While one MSSM singlet field interacts with the MSSM Higgs fields, three of…
We consider a string inspired non-supersymmetric extension of the standard model with gauged anomalous U(1) flavor symmetries. Consistency requires the Green-Schwarz mechanism to cancel mixed anomalies. The additional required scalars…