相关论文: Z' Gauge Models from Strings

Present experiments are sensitive to very weakly coupled extra gauge symmetries which motivates further investigation of their appearance in string theory compactifications and subsequent properties. We consider extensions of the standard…

Four-dimensional string theories predict in general the existence of light exotic particles with fractional electric charges. Such particles could escape present observations if they are confined by a gauge group of the "hidden" sector into…

Additional Z' gauge bosons are predicted by a wide variety of extensions of the standard model (SM). Possibilities include TeV-scale bosons with electroweak coupling, very light bosons which nearly decouple from the standard model…

We argue for the existence of additional constraints on SU(2) gauge theories in four dimensions when realized in ultraviolet completions admitting an analog of D-brane nucleation. In type II string compactifications these constraints are…

We present a consistency condition for 8d ${\cal N} = 1$ supergravity theories with non-trivial global structure $G/Z$ for the non-Abelian gauge group, based on an anomaly involving the $Z$ 1-form center symmetry. The interplay with other…

New strong gauge interactions remain a viable source for the electroweak symmetry breaking. However, addressing the generation of fermion masses remains a challenge. A basic observable which provides stringent constraints on the flavor…

We study low energy implications of F-theory GUT models based on $SU(5)$ extended by a $U(1)'$ symmetry which couples non-universally to the three families of quarks and leptons. This gauge group arises naturally from the maximal…

We present a string-inspired/derived supergravity model based on the flipped $SU(5)\times U(1)$ structure supplemented by a minimal set of additional matter representations such that unification occurs at the string scale…

Many extension of the standard model contain an extra U(1)' gauge group with a heavy Z' gauge boson. Perhaps the most clear signal for such a Z' would be a resonance in the invariant mass spectrum of the lepton pairs to which it decays. In…

In the superstring models we have not only the complete {\bf 27} multiplets of $E_6$ but also extra incomplete $({\bf 27}+{\overline {\bf 27}})$ chiral supermultiplets being alive at low energies. Associated with these additional…

We hypothesise that all electroweak symmetry breaking terms such as fermion masses and the W and Z gauge boson masses arise radiatively from just one explicit symmetry breaking term in the Lagrangian. Our hypothesis is motivated by the lack…

We present an overview of the simplest supergravity models which enforce radiative breaking of the electroweak symmetry, namely the minimal $SU(5)$ supergravity model and the class of string-inspired/derived supergravity models based on the…

The ATLAS collaboration reported excesses at around 2 TeV in the di-boson production decaying into hadronic final states. We consider the possibility of explaining the excesses with extra gauge bosons in two simple non-Abelian extensions of…

Spontaneously broken Abelian gauge symmetries can explain the fermion mass hierarchies of the minimal supersymmetric standard model. In most cases it is assumed that the $U(1)_H$ symmetry is anomalous. However, non-anomalous models are also…

We find the spectrum of magnetic monopoles produced in the symmetry breaking SU(5) to [SU(3)\times SU(2)\times U(1)']/Z_6 by constructing classical bound states of the fundamental monopoles. The spectrum of monopoles is found to correspond…

Within the framework of the Standard Model, the scale of electroweak symmetry breaking is unstable to radiative corrections. We discuss two broad classes of models of new physics (one with a strongly interacting and the other with a…

The electroweak (EW) symmetry breaking in the simplest supersymmetric (SUSY) extensions of the standard model (SM), i.e. minimal and next-to-minimal supersymmetric standard models (MSSM and NMSSM), is considered. The spectrum of the Higgs…

In the $SU(6) \times SU(2)_R$ string-inspired model, we evolve the couplings and the masses down from the string scale $M_S$ using the renormalization group equations and minimize the effective potential. This model has the flavor symmetry…

We study gaugino condensation in presence of an anomalous $U(1)$ gauge group and find that global supersymmetry is dynamically broken. An example of particular interest is provided by effective string models with 4-dimensional Green-Schwarz…

In spite of its many successes, the Standard Model makes many empirical assumptions in the Higgs and fermion sectors for which a deeper theoretical basis is sought. Starting from the usual gauge symmetry $u(1) \times su(2) \times su(3)$…