Showing papers in "Nuclear Physics in 1988"

TL;DR: By disentangling the hamiltonian constraint equations, 2 + 1 dimensional gravity (with or without a cosmological constant) is shown to be exactly soluble at the classical and quantum levels.

TL;DR: In this paper, the cosmological constant problem in the light of dilatation symmetry and its possible anomaly is discussed, and it is shown that the energy-momentum tensor in the vacuum is purely anomalous and that deviations from the standard hot big bang cosmology are possible.

TL;DR: In this paper, the authors studied conformal field theories with a finite number of primary fields with respect to some chiral algebra and showed that the fusion rules are completely determined by the behavior of the characters under the modular group.

TL;DR: In this article, the authors consider scale invariant theories which couple gravity to Maxwell fields and antisymmetric tensor fields with a dilaton field, and they exhibit in a unified way solutions representing black hole, space-time membrane, vortex and cosmological solutions.

TL;DR: In this paper, the authors studied the high-energy behavior of string scattering amplitudes to all orders in perturbation theory, with the aim of exploring the short distance structure of string theory.

TL;DR: In this paper, upper bounds on all superparticle masses as functions of the top quark mass are derived based on the "naturalness" criterion, which gives an objective criterion to test (or disprove) the idea of low energy supersymmetry, as implemented in supergravity models.

TL;DR: The supermembrane can be viewed as a limiting case of a class of models in supersymmetric quantum mechanics and its ground state can be examined in this article, where the complexity of the ground state and various truncations of these models are examined.

TL;DR: In this paper, a method is presented in which multigluon processes are calculated recursively, explicitly developed for processes where only gluons are produced and processes where in addition to the Gluons also a quark-antiquark pair with or without a vector boson or e + e − pair are present.

TL;DR: In this article, it was shown that the k-loop contribution to the free energy at temperatures far above the Hagedorn temperature leads to a number of interesting speculations about the underlying degrees of freedom in string theory.

TL;DR: In this paper, the authors present the results of a full calculation of the QCD O(a$) radiative corrections to the total cross-aection for the production of a heavy quark pair.

TL;DR: In this article, it was shown that wormholes can have the effect of making the cosmological constant vanish, and that wormhole topology changing configurations in euclidean quantum gravity have been advocated by several authors.

TL;DR: In this paper, the authors extended the analysis of the low-energy structure of Green functions in QCD to processes with one external nucleon and determined the elastic π N scattering amplitude T π n for off-shell pions to one loop.

TL;DR: In this paper, the authors extended their previous work on the simulation of coherent soft-gluon radiation to hard collisions that involve incoming as well as outgoing coloured partons, and proposed a new Monte Carlo program which incorporates this procedure, together with other new features such as azimuthal correlations due to gluon polarization and interference.

TL;DR: The topological fluctuations recently suggested by Hawking, by Giddings and Strominger, and by Lavrelashvili, Rubakov, and Tinyakov do not lead to an observable loss of quantum coherence as discussed by the authors.

TL;DR: In this paper, it was shown that the anomalies arise from the tadpole of an unphysical field, and cannot be removed by any choice of background, and that the spacetime anomalies are due to a world-sheet superconformal anomaly of topological origin.

TL;DR: In this paper, the wave function of an interacting family of one large parent and many Planck-sized "baby" universes is computed in a semiclassical approximation using an adaptation of Hartle-Hawking initial conditions.

TL;DR: In this article, instantons are found which describe the nucleation of a Planck-sized baby Robertson-Walker universe and an estimate of the magnitude of this effect on particle propagation is made in the semi-classical approximation.

TL;DR: In this paper, the consequences of extended spacetime supersymmetry for classical superstring vacua with four dimensions uncompactified were examined, and it was shown that the effective field theories for classical vacua of superstring theories have no continuous global symmetries.

TL;DR: In this paper, the QCD evolution of initial jets (corresponding to space-like partons) is analyzed for small Bjorken x. Coherent effects are described by a gluon emission current which also embodies internal line insertions to double log accuracy.

TL;DR: In this paper, the authors considered the quantum creation of closed membranes by totally antisymmetric tensor and gravitational fields in arbitrary space-time dimension, and described the creation event by instanton tunneling.

TL;DR: In this article, the authors present predictions of random cascading models for multiparticle production at high energy, using the central limit theorem to test directly for the existence of a cascading process.

TL;DR: In this article, the authors investigated a class of Calabi-Yau spaces for which the manifold may be represented as a complete intersection of polynomials in a product of projective spaces.

TL;DR: In this paper, the relation between invariance under rigid and local changes of length scale was studied in two dimensions and three dimensions, and it was shown that the rigid invariance implies the local under broad conditions.

TL;DR: In this paper, the authors show how to compute one-loop corrections to these relations for any four-dimensional model based on a classical vacuum of the heterotic string, which can be used to calculate both sin2θW and ΛQCD in terms of αQCD and MPlanck.

TL;DR: In this article, the authors present a non-equilibrium method for studying anomalous B -nonconservation in the electroweak theory at finite temperature, and derive formally the equation of B -evolution advocated previously on physical grounds.

TL;DR: In this article, the O(32) superstring has been renormalized by cancelling BRST anomalies between different genus worldsheets, and the loop-order source terms which necessarily break conformal invariance are added to these equations.

TL;DR: In this article, complex fragments of 3 Z ⪅35 have been detected in reverse-kinematics reactions of 93 Nb plus 9 Be, 12 C and 27 Al at bombarding energies of E / A = 11.4, 14.7 and 18.0 MeV.

TL;DR: The mass dependence of the spherical harmonic moments provided clear evidence for the production of the complete leading orbitally excited K∗ series up through JP = 5− as discussed by the authors, and also provided new evidence for underlying states.

TL;DR: In this paper, the authors investigate the interaction of neutrinos with a thermal background in the framework of the standard model of weak interactions and calculate the lowest order contribution to the refractive index, including the imaginary part and corrections from the finite gauge boson masses.