Related papers: A QCD R-Axion
We discuss the role of the U(1) axial symmetry for the phase structure of QCD at finite temperature. In particular, supported by recent lattice results, we analyse a scenario in which a U(1)-breaking condensate survives across the chiral…
It is suggested that various hierarchy problems in supersymmetric standard model, i.e. the Yukawa hierarchies, the \mu problem, and the suppression of dangerous baryon and/or lepton number (B/L) violating couplings, are resolved altogether…
I remark that the weak mixing angle in the standard model may be computed even in the absence of a grand unification symmetry. In particular, if there is an additional gauged $U(1)$ symmetry at some large scale which can be made…
We present a composite QCD axion model where the Peccei--Quinn (PQ) symmetry emerges as a high-quality, accidental symmetry. The axion potential is only modified by eight-fermion, dimension 12 operators, which if present at the Planck…
Non-supersymmetric Grand Unified $SO(10)\times U(1)_{\rm PQ}$ models have all the ingredients to solve several fundamental problems of particle physics and cosmology -- neutrino masses and mixing, baryogenesis, the non-observation of strong…
Space-time parity can solve the strong CP problem and introduces a spontaneously broken $SU(2)_R$ gauge symmetry. We investigate the possibility of baryogenesis from a first-order $SU(2)_R$ phase transition similar to electroweak…
The patterns of $R$ violation resulting from imposition of a gauged U(1) horizontal symmetry on the minimal supersymmetric standard model are systematically analyzed. We concentrate on class of models with integer U(1) charges chosen to…
We provide a simple solution to the $\mu$ and strong CP problems in the context of gauge mediated supersymmetry breaking. The generic appearance of R symmetry in dynamical supersymmetry breaking is used to implement Peccei-Quinn symmetry.…
We propose a new solution to the strong-CP problem. It involves the existence of an unbroken gauged $U(1)_X$ symmetry whose gauge boson gets a Stuckelberg mass term by combining with a pseudoscalar field $\eta (x)$. The latter has…
We investigate the string solutions and cosmological implications of the gauge ${\rm U(1)_Z}\,\times$ global ${\rm U(1)_{PQ}}$ model. With two hierarchical symmetry-breaking scales, the model exhibits three distinct string solutions: a…
The patterns of R violation resulting from imposition of a gauged U(1) horizontal symmetry, on the minimal supersymmetric standard model are systematically analyzed. We concentrate on a class of models with integer U(1) charges chosen to…
We outline some general features of possible extensions of the Standard Model that include anomalous U(1) gauge symmetries, a certain number of axions and their mixings with the CP-odd Higgs sector. As previously shown, after the mixing one…
We present a class of models based on a gauged $U(1)_F$ flavor symmetry that explains the hierarchical structure of fermion masses and mixings via the Froggatt-Nielsen (FN) mechanism, while also solving the strong CP problem by the…
The QCD axion provides an elegant solution to the Strong CP Problem. While the minimal realization is vulnerable to the so-called "Axion Quality Problem", we will consider a more robust realization in the presence of a mirror sector related…
We study the consequences of the existence and breaking of a Peccei--Quinn symmetry within the context of a dynamical model of electroweak symmetry breaking based on broken gauged flavour symmetries. We perform an estimate of the axion mass…
We address the tachyonic slepton problem of anomaly mediated supersymmetry breaking using abelian D-terms. We demonstrate that the most general extra U(1) symmetry that does not disrupt gauge coupling unification has a large set of possible…
We introduce a new class of $U(1)_X$ symmetries where all Standard Model fermions are ``chiral," i.e., the left- and right-handed components have different charges under the $U(1)_X$ symmetry. Gauge anomaly cancellation is achieved by…
We explore a class of axion models where an accidental $\mathrm{U}(1)$ Peccei-Quinn (PQ) symmetry automatically emerges from the interplay of vertical (grand-unified) and horizontal (flavor) gauge symmetries. We study a specific Pati-Salam…
We stress that a natural solution of the $\mu$ problem requires two ingredients: a symmetry that would enforce $\mu = 0$ as well as the occurence of a small breaking parameter that generates a nonzero $\mu$. It is suggested that both the…
The model of the supersymmetrical ball in the supersymmetrical standard model with additional global U(1) fermion symmetry is presented. We show that the supersymmetry breaking scale ( R-parity ), the global U(1) fermion symmetry scale and…