International Journal of Modern Physics A

Invariance under finite conformal transformations in Minkowski space and the Wightman axioms imply strong locality (Huygens principle) and rationality of correlation functions, thus providing an extension of the concept of vertex algebra to higher dimensions. Gibbs (finite temperature) expectation values appear as elliptic functions in the conformal time. We survey and further pursue our program of constructing a globally conformal invariant model of a Hermitian scalar field ℒ of scale dimension four in Minkowski space–time which can be interpreted as the Lagrangian density of a gauge field theory.

We consider orbifolds of two-dimensional unitary toroidal superconformal field theories with target spaces of arbitrary dimensions, where the orbifold group involves the space–time fermion number operator. We construct all so-called superaffine, orbifold prime and super-M-orbifold models by generalizing the constructions of Dixon, Ginsparg and Harvey. We also correct claims made by Dixon, Ginsparg and Harvey about multicritical points among those models with central charge .

The explicit semiclassical treatment of logarithmic perturbation theory for the bound-state problem within the framework of the radial Klein–Gordon equation with attractive screened Coulomb potentials, contained time-component of a Lorentz four-vector and a Lorentz-scalar term, is developed. Based upon ℏ-expansions and new quantization conditions a novel procedure for deriving perturbation expansions is offered. Avoiding disadvantages of the standard approach, new handy recursion formulae with the same simple form both for ground and excited states have been obtained. As an example, the perturbation expansions for the energy eigenvalues for the Hulthén potential containing the vector part as well as the scalar component are considered.

The lifetime differences of bottom hadrons are known to be properly explained within the framework of heavy quark effective field theory (HQEFT) of QCD via the inverse expansion of the dressed heavy quark mass. In general, the spectrum around the endpoint region is not well behaved due to the invalidity of 1/m_Q expansion near the endpoint. The curve fitting method is adopted to treat the endpoint behavior. It turns out that the endpoint effects are truly small and the explanation on the lifetime differences in the HQEFT of QCD is then well justified. The inclusion of the endpoint effects makes the prediction on the lifetime differences and the extraction on the CKM matrix element |V_cb| more reliable.

In this paper we will study quantum field theory of fluctuation modes around the rolling tachyon solution on non-BPS D-brane effective action. The goal of this paper is to study particle production during the decay of non-BPS D-brane and explore possible relation with minisuperspace calculation. We find that the number of particles produced on half S-brane exponentially grows for large time which suggests that linearized approximation breaks down and also that backreaction of fluctuation field on classical solution should be taken into account.

Large scale airshower simulations around the GZK cutoff are performed. An extensive analysis of the behaviour of the various subcomponents of the cascade is presented. We focus our investigation both on the study of total and partial multiplicities along the entire atmosphere and on the geometrical structure of the various cascades, in particular on the lateral distributions. The possibility of detecting new physics in Ultra High Energy Cosmic Rays (UHECR) at AUGER is also investigated. We try to disentangle effects due to standard statistical fluctuations in the first proton impact in the shower formation from the underlying interaction and comment on these points. We argue that theoretical models predicting large missing energy may have a chance to be identified, once the calibration errors in the energy measurements are resolved by the experimental collaborations, in measurements of inclusive multiplicities.

We present a model of a nonlinear electrodynamics with two potentials that allows the signals to propagates with constant velocity, as in linear Maxwell theory, and exhibit dual-symmetry.