Showing papers in "Nuclear Physics in 1992"

TL;DR: In this paper, a detailed derivation of a new and efficient technique based on the technology of four-dimensional heterotic strings, for computing one-loop amplitudes in gauge theories, along with expressions for the dimensionally regularized helicity amplitudes for the process with four external gluons.

TL;DR: In this paper, the authors consider string theory in the background of the two-dimensional black hole as described by the SL(2, R )/U(1) coset theory recently untroduced by Witten.

TL;DR: In this article, the authors presented a calculation of the fully exclusive parton cross sections for heavy-quark production at order O( α S 3 ) in QCD, where α is the number of quarks in the system.

TL;DR: The generalization of R → 1/R duality to arbitrary conformally invariant σ-models with an isometry was studied in this paper, where it was shown that any pair of dual σ models can be represented as quotients of a self-dual σ model obtained by gauging different combinations of chiral currents.

TL;DR: In this paper, the Schrodinger functional in lattice gauge theories without matter fields has a well-defined continuum limit and can be used to study the scaling properties of the theory and in particular the evolution of the renormalized gauge coupling.

TL;DR: In this article, a reinterpretation of the universal cover of the) recently studied two-dimensional black hole solution as a conformal realization of cosmological solutions found previously by Mueller is presented.

TL;DR: In this paper, the total τ hadronic width can be accurately calculated using analyticity and the operator product expansion, and the theoretical analysis of this observable is updated to include all available perturbative and nonperturbative corrections.

TL;DR: In this article, the structure of QCD Green functions with one external nucleon, treated as a very massive field, was analyzed and the matching conditions and relations of various nucleon matrix elements of quark currents to the relativistic approach were discussed.

TL;DR: In this paper, a general classification of all possible modular weights of massless fields in Abelian orbifolds is presented, and a general analysis of the possible relevance of those threshold corrections to the computation of sin 2 θW and α3 for all Abelian ABJ-like 4-D strings is presented.

TL;DR: In this article, a general classification of discrete Z N symmetries (and R-symmetries) is given and the number of independent possibilities is substantially reduced by equivalences.

TL;DR: In this paper, the connection between standard perturbation theory techniques and the new Bern-Kosower calculational rules for gauge theory is clarified, and the effective actions of scalars, Dirac spinors, and vector bosons in a background gauge field are derived without the use of either string theory or Feynman diagrams.

TL;DR: In this paper, a cosmological constant Λ was used to classify the cold black holes and, for positive Λ, the "lukewarm" black holes at the same temperature as the de Sitter thermal background.

TL;DR: In this article, the background fields of the SO(32) superstring were shown to be genuine moduli, since their amplitudes vanish when the momenta are all scaled to zero.

TL;DR: In this paper, the integrability of the system of PDE for dependence on coupling parameters of the (tree-level) primary partition function in massive topological field theories, being imposed by the associativity of the perturbed primary chiral algebra, is proved.

TL;DR: In this paper, the authors studied the twist-two and twist-three chiral-odd parton distributions, h 1 ( x ), h L ( x ) and e( x ), which appear in the quark density matrix of the nucleon.

TL;DR: In this paper, a ground ring of operators of spin (0, 0) is characterized by the existence of an area-preserving diffeomorphism of a two-dimensional phase space that preserves the Fermi surface of the matrix model.

TL;DR: In this article, it was shown that certain one-loop corrections to superstring effective four-dimensional lagragians, involving non-harmonic field-dependent renormalization of gauge couplings, can be consistently written in a standard N = 1 supergravity form, preserving target-space duality.

TL;DR: In this paper, it was shown that Tr(−1) F F e βH is an index for N = 2 supersymmetric theories in two dimensions, in the sense that it is independent of almost all deformations of the theory.

TL;DR: In this paper, the authors re-evaluate the constraints on such particles from the possible effects of their decays on the spectrum of the microwave background-radiation and the primordially synthesised abundances of the light elements, from observations of the diffuse gamma-ray background radiation, and from searches for muons and neutrinos in nucleondecay and cosmic-ray detectors.

TL;DR: In this paper, the existence of a non-renormalizable infinity in the two-loop effective action of perturbative quantum gravity by means of an explicit calculation was proved, and the background-field method in coordinate space, combined with dimensional regularization and a heat kernel representation for the propagators, was used.

TL;DR: In this paper, the authors set the framework for a model-independent analysis of the data on electroweak precision tests, starting from three basic observables, the mass ratio m w / m z, the Z partial width and the forward-backward asymmetry for changed leptons, they define three dimensionless parameters ϵ 1, ϵ 2 and ϵ 3 which contain the snall radiative correction effects one is interested in, with large m t -effects only appearing in ϵ1.

TL;DR: In this paper, the energy levels required for the calculations are obtained from the folded-Yukawa single-particle model for ground-state shapes obtained in the macroscopic-microscopic approach by minimizing the total potential energy with respect to ϵ 2 and ϵ 4 shape degrees of freedom.

TL;DR: In this paper, the authors present simple algorithmic Feynman rules for fermion-number-violating interactions, which do not involve explicit charge-conjugation matrices and resemble closely the familiar Dirac fermions.

TL;DR: In this article, a modified perturbative expression for the pion electromagnetic form factor in perturbive QCD was given, which includes Sudakov suppression of the elastic scattering of quarks that are isolated in space.

TL;DR: In this article, the effects of next-to-leading corrections on the Wilson coefficients of current-current and QCD penguin operators are analyzed. But the results are restricted to the case of γ5 and γ4.

TL;DR: In this paper, it has been shown that the N matrix model of two-dimensional gravity is related to certain topological field theories obtained by twisting the N = 2 minimal models, which leads to an algebrogeometric description of the topological correlation functions from which many of their standard properties can be recovered.

TL;DR: In this paper, a new method of regularization is developed in which singular functions are written as derivatives of less singular functions which contain a logarithmic mass scale, and the Fourier transform is then defined by formal integration by parts.

TL;DR: In this article, the massless limit of the eikonal approximation is compared to other approximations for the same process, specifically the semiclassical calculation due to G. 't Hooft and the topological field theory due to H. and E. Verlinde.

TL;DR: In this paper, it is shown that the behavior of these extreme-dilation black holes, which from the point of view of traditional black-hole theory seems quite bizarre, can reasonably be interpreted as the holes doing their best to behave like normal elementary particles.