International Journal of Modern Physics A

The prospects for discovering Higgs particles and studying their fundamental properties at future high-energy electron-positron and hadron colliders are reviewed. Both the Standard Model Higgs boson and the Higgs particles of its minimal supersymmetric extension are discussed. We update various results by taking into account the new value of the top-quark mass obtained by the CDF Collaboration, and by including radiative corrections, some of which have been calculated only recently.

We investigate spinor fields on phase spaces. Under local frame rotations they transform according to the (infinite-dimensional, unitary) metaplectic representation of Sp(2N), which plays a role analogous to the Lorentz group. We introduce a one-dimensional nonlinear sigma model whose target space is the phase space under consideration. The global anomalies of this model are analyzed, and it is shown that its fermionic partition function is anomalous exactly if the underlying phase space is not a spin manifold, i.e. if metaplectic spinor fields cannot be introduced consistently. The sigma model is constructed by giving a path integral representation to the Lie transport of spinors along the Hamiltonian flow.

For any manifold M we introduce a ℤ-graded differential algebra Ξ, which, in particular, is a bimodule over the associative algebra C(M⋃M). We then introduce the corresponding covariant differentials and show how this construction can be interpreted in terms of Yang-Mills and Higgs fields. This is a particular example of noncommutative geometry. It differs from the prescription of Connes in the following way: the definition of Ξ does not rely on a given Dirac-Yukawa operator acting on a space of spinors.

We find a new Hamiltonian formulation of the classical isotropic rotator where left and right SU(2) transformations are not canonical symmetries but rather Poisson Lie group symmetries. The system corresponds to the classical analog of a quantum-mechanical rotator which possesses quantum group symmetries. We also examine systems of two classical interacting rotators having Poisson Lie group symmetries.

We consider the gauging of SL(2, R) and SL(2, R)×U(1) WZNW model by their nilpotent subgroups. The resulting space-times of the corresponding sigma models are seen to collapse to the one-dimensional Liouville theory in the first case, and lead to an extremal three-dimensional black string in the second case. We show that these results are also obtained by boosting the Witten black hole solution and Horne and Horowitz black string solution respectively.

In this paper we calculate the neutrino absorption cross-sections for the reaction ⁷¹Ga(ν, e−)⁷¹Ge using two simple nuclear models to account for the giant GT resonances. In both models the excited state contributions are found to have significant ranges of variation and affect the solar neutrino capture rates. Nonetheless, the regions in the neutrino mixing angle-mass squared difference plane allowed by the data from the Gallium detectors, when taken together with those from the Chlorine and Kamioka experiments, are found to be comparatively stable.