International Journal of Modern Physics A

We find the potential per unit length between two nonintersecting D1-branes as a function of their relative angle.

We analyze the Hilbert space structure of the isomorphic gauge noninvariant and gauge-invariant bosonized formulations of chiral QCD₂ for the particular case of the Jackiw–Rajaraman parameter a=2. The BRST subsidiary conditions are found not to provide a sufficient criterium for defining physical states in the Hilbert space and additional superselection rules must be taken into account. We examine the effect of the use of a redundant field algebra in deriving basic properties of the model. We also discuss the constraint structure of the gauge-invariant formulation and show that there are only primary constraints, and they are first-class.

We construct a bilinear form on the periods of Calabi–Yau spaces. This is used to obtain the prepotentials around conifold singularities in type II strings compactified on Calabi–Yau space. Explicit construction of the bilinear forms is achieved for the one-modulus models as well as two-modulus models with K3 fibrations where the enhanced gauge symmetry is known to be observed at the conifold locus. We also show how these bilinear forms are related with the existence of flat coordinates. We list the resulting prepotentials in two-modulus models around the conifold locus, which contains α′ corrections of 4D N=2 SUSY SU(2) Yang–Mills theory as the stringy effect.

It is suggested that the experimental data on the solar neutrino flux as measured in the existing solar neutrino detectors (e.g. Homestake, Kamiokande II and III, Gallex and Sage) vary with the solar activity cycle to a very high level of statistical significance. We have applied the run test and the change point test to the nine sets of solar neutrino flux that have been generated by the Monte-Carlo simulation with production rate and background parameters that are typical of those in the actual Homestake experiment. Homestake solar neutrino flux data show anticorrelation with sunspot numbers from 1970 to February 1994 at a very high level of statistical significance. However, the Kamiokande solar neutrino flux data show correlation with the sunspot number data at a significant level. Again it is shown that out of nine Monte-Carlo-simulated data only three indicate a variation within the period from 1970 to February 1992, but these three Monte-Carlo-simulated solar neutrino flux data do not show significant anticorrelation with the sunspot number data. The solar neutrino flux data from Gallex and Sage show not only variation within the measurement period, i.e. from January 1990 to October 1995, but are also correlated with the sunspot numbers. The Kamiokande solar neutrino flux data not only show variation from January 1987 to February 1995 but are also correlated with the sunspot number data. The variation of solar neutrino flux data within the solar activity cycle and anticorrelation/correlation indicates that the solar activity cycle is due to the pulsating character of the nuclear energy generation inside the core of the sun.

In this paper we develop a general method for constructing three-point functions in conformal field theory with affine Lie group symmetry, continuing our recent work on two-point functions. The results are provided in terms of triangular coordinates used in a wave function description of vectors in highest weight modules. In this framework, complicated couplings translate into ordinary products of certain elementary polynomials. The discussions pertain to all simple Lie groups and arbitrary integrable representation. An interesting by-product is a general procedure for computing tensor product coefficients, essentially by counting integer solutions to certain inequalities. As an illustration of the construction, we consider in great detail the three cases SL(3), SL(4) and SO(5).

The process of top-quark pair production followed by semileptonic decays at future high-energy e⁺ e^- linear colliders is investigated as a possible test of physics beyond the Standard Model. Assuming the most general nonstandard forms for , and Wtb couplings, the energy spectrum of the single lepton ℓ^± and the energy correlation of ℓ⁺ and ℓ^- emerging from the process are calculated. Expected precision of the nonstandard-parameter determination is estimated adopting the recently-proposed optimal method.

For each N an infinite number of conformal field theories is presented that has the same fusion rules as SO(N) level 2. These new theories are obtained as extensions of the chiral algebra of SO(NM²) level 2, and correspond to new modular invariant partition functions of these theories. A one-to-one map between the c=1 orbifolds of radius R²=2r and D_r level 2 plays an essential role.

We study the one-loop effective action for N 4D conformally invariant scalars on the spherically symmetric background. The main part of the effective action is given by integration of the 4D conformal anomaly. This effective action (in large N approximation and partial curvature expansion) is applied to investigate the quantum evolution of Schwarzschild–de Sitter (SdS) black holes of maximal mass. We find that the effect (recently discovered by Bousso and Hawking for N minimal scalars and another approximate effective action) of antievaporation of nearly maximal SdS (Nariai) black holes also occurs in the model under consideration. Careful treatment of quantum corrections and perturbations modes of Nariai black holes is given, being quite complicated. It is shown that exists also perturbation where the black hole radius shrinks, i.e. the black hole evaporates. We point out that our result holds for a wide class of models, including conformal scalars, spinors and vectors. Hence, antievaporation of SdS black holes is a rather general effect which should be taken into account in quantum gravity considerations.

By exploiting the relation between Fredholm modules and the Segal–Shale–Stinespring version of canonical quantization, and taking as starting point the first-quantized fields described by Connes' axioms for noncommutative spin geometries, a Hamiltonian framework for fermion quantum fields over noncommutative manifolds is introduced. We analyze the ultraviolet behavior of second-quantized fields over noncommutative three-tori, and discuss what behavior should be expected on other noncommutative spin manifolds.