Modern Physics Letters A

Pseudo-Nambu–Goldstone bosons (pNGBs) are simple and elegant candidates for radiatively stable models of quintessence and inflation. In this brief review, we first examine the observational status of pNGB-driven quintessence and inflation. We then discuss the construction of theoretically as well as observationally viable models of cosmological pNGBs. Special emphasis will be given to the constructions of models compatible with the requirements from String Theory.

A class of topological field theories like the BF model and Chern–Simons theory, when quantized in the Landau gauge, enjoys the property of invariance under a vector supersymmetry, which is responsible for their finiteness. We introduce a new type of gauge fixing which makes these theories invariant under an extended BRS symmetry, containing a new type of field, the ghost of diffeomorphisms. The presence of such an extension is naturally related to the vector supersymmetry discussed before.

For non-Abelian tensor gauge fields, we found an alternative form of duality transformation which maps the Lagrangian forms into each other and has the property that the direct and the inverse transformations coincide.

The Pisano–Pleitez–Frampton 3-3-1 model is revisited here within the framework of the general method for solving gauge models with high symmetries. This exact algebraical approach — proposed several years ago by one of us — was designed to include a minimal Higgs mechanism that spontaneously breaks the gauge symmetry up to the universal U(1)_em electromagnetic one and, consequently, to supply the mass spectrum and the couplings of the currents for all the particles in the model. We prove in this paper that this powerful tool, when is applied to the PPF 3-3-1 model, naturally recovers the whole Standard Model phenomenology and, in addition, predicts — since a proper parametrization is employed — viable results such as: (i) the exact expressions for the boson and fermion masses, (ii) the couplings of the charged and neutral currents and (iii) a plausible neutrino mass pattern. A generalized Weinberg transformation is implemented, while the mixing between the neutral bosons Z and Z′ is performed as a necessary step by the method itself. Some phenomenological consequences are also sketched, including the strange possibility that simultaneously m(Z) = m(Z′) and m(W) = m(V) hold.

In continuation of our previous works, we attempt here to understand the nature of data on direct photon and neutral pion production in the latest RHIC experiments at for all the different interactions studied therein from the viewpoint of a nonstandard outlook and approach as described in Refs. 4 and 5 here. It is found that the proposed model could account for the data-sets with a fair degree of success.

Possible single productions of the fourth standard model family charged leptons via anomalous interactions at the future ep colliders are studied. Signatures of such anomalous processes and backgrounds are discussed in detail.

By using the gauge potential decomposition, we discuss the self-dual equation and its solution in Jackiw–Pi model. We obtain a new concrete self-dual equation and find relationship between Chern–Simons vortices solution and topological number which is determined by Hopf indices and Brouwer degrees of Ψ-mapping. To show the meaning of topological number we give several figures with different topological numbers. In order to investigate the topological properties of many vortices, we use five parameters (two positions, one scale, one phase per vortex and one charge of each vortex) to describe each vortex in many vortices solutions in Jackiw–Pi model. For many vortices, we give three figures with different topological numbers to show the effect of the charge on the many vortices solutions. We also study the quantization of flux of those vortices related to the topological numbers in this case.