Modern Physics Letters A

The non-Abelian BF theories in arbitrary dimensions are studied in a generalized connection formalism. This gives rise to the off-shell nilpotent BRST operator which permits construction of BRST exact quantum action. A set of operators satisfying the descent equations is derived from the generalized curvature; but it cannot lead to non-trivial observables. An off-shell superalgebra of Wess–Zumino type, containing the vector supersymmetry and the BRST symmetry, is also derived.

The form factors for the weak currents between B and light mesons are studied by relating them to the corresponding D form factors at according to HQET, by evaluating them at q²=0 by QCD sum rules, and by assuming a polar q² dependence. The results found are consistent with the information obtained from exclusive non-leptonic two-body decays and, with the only exception of A₁, with lattice calculations.

The BRST approach is applied to describe the irreducible massless higher spins representation of the Poincaré group in arbitrary dimensions. The total system of constraints in such theory includes both first- and second-class constraints. The corresponding nil-potent BRST charge contains terms up to the seventh degree in ghosts.

A scalar sector of the 3 3 1 model with three Higgs triplets is considered in detail. The mass spectrum, eigenstates and interactions of the Higgs and the SM gauge bosons are derived. We show that one of the neutral scalars can be identified with the standard model Higgs boson, and in the considered potential, there is no mixing between scalars having vev and those without vev.

If one encodes the gravitational degrees of freedom in an orthonormal frame field, there is a very natural first-order action one can write down (which in four dimensions is known as the Goldberg action). In this letter we will show that this action contains a boundary action for certain microscopic degrees of freedom living at the horizon of a black hole, and argue that these degrees of freedom hold great promise for explaining the microstates responsible for black hole entropy, in any number of space–time dimensions. This approach faces many interesting challenges, both technical and conceptual.

We exhibit a resonance mechanism of amplification of density perturbations in inflationary models, using a minimal set of ingredients (an effective cosmological constant, a scalar field minimally coupled to the gravitational field and matter), common to most models in the literature of inflation. This mechanism is based on the structure of homoclinic cylinders, emanating from an unstable periodic orbit in the neighborhood of a saddle-center critical point, present in the phase space of the model. The cylindrical structure induces oscillatory motions of the scales of the universe whenever the orbit visits the neighborhood of the saddle-center, before the universe enters a period of exponential expansion. The oscillations of the scale functions produce, by a resonance mechanism, the amplification of a selected wave number spectrum of density perturbations, and can be used to explain the hierarchy of scales observed in the actual universe. The transversal crossings of the homoclinic cylinders induce chaos in the dynamics of the model — a fact closely connected to the resonance mechanism occuring immediately before the exit to inflation.

In this letter we present a mechanism in which new nonperturbative solutions of quantum electrodynamics in four dimensions is found. Two nonperturbative solutions are found for approximate Schwinger–Dyson equations. The mass ratio of the three solutions (one of them is the ordinary solution) is approximately 1: (8π/α)^2/3 : 8π/α, which is close to the realistic mass ratio of e^-, μ^- and τ^-.

We show that the finite difference, -iπ²m², between quadratic and logarithmic divergent integrals ∫d⁴p[m² (p²-m²)^-2 - (p²-m²)^-1], as encountered in the linear σ-model, is in fact regularization independent.

An interaction of a pseudoscalar particle with two photons induced by an external electromagnetic field is used to study the photon decay γ→γa where a is a pseudoscalar particle associated with the Peccei–Quinn U(1) symmetry. The field-induced axion emission by photon is analyzed as a possible source of energy losses by astrophysical objects.

We derive a set of complex potentials which linearize the action of charging symmetries of the stationary Einstein–Maxwell dilaton–axion theory.