July 1994 arXiv papers — page 6

L. V. Avdeev, M. V. Chizhov

The classical dynamics of antisymmetric second-rank tensor matter fields is analyzed. The conformally invariant action for the tensor field leads to a positive-definite hamiltonian on the class of the solutions that are bounded at the time infinity (plane waves). Only the longitudinal waves contribute to the energy and momentum. The helicity proves to be equ

R. Emparan

We point out that using the heat kernel on a cone to compute the first quantum correction to the entropy of Rindler space does not yield the correct temperature dependence. In order to obtain the physics at arbitrary temperature one must compute the heat kernel in a geometry with different topology (without a conical singularity). This is done in two ways, w

Zhi-zhong Xing

Considering that the existing experimental limit for $CPT$ violation is still poor, we explore various possible ways to test $CPT$ symmetry in $CP$-violating $B$ decays at $e^{+}e^{-}$ $B$ factories. We find that it is difficult to distinguish between the effect of direct $CP$ violation and that of $CPT$ violation in the time-integrated measurements of neutr

Dongsheng DU, Zhi-zhong XING

We make a further study of $CP$ asymmetries in the pure penguin-induced decay modes $B^{-}_{u}\rightarrow K^{(*)0} + K^{(*)-}$ and $B^{-}_{u} \rightarrow \bar{K}^{(*)0} + (π^{-}, ρ^{-}, a^{-}_{1})$ by using the two-loop renormalization-group-improved effective Hamiltonian and factorization approximation. Different from the previous results obtained without Q

Huazhong Zhang

One of the interesting features in unification models and supersymmetric unification models is that the chiral states of quarks and leptons in a family including a right-handed neutrino can be fitted neatly into a fundamental spinor representation (f.s) of dimension 16 for the SO(10) gauge group. However, it is shown in this paper that such a fundamental spi

Q. Haider, L. C. Liu

The dynamical content of rho-N-N and rho-N-Delta vertex functions is studied with a mesonic model. A set of coupled integral equations satisfied by these vertex functions were solved self-consistently. These soulutions indicate that the dominant mesonic content arises from di-pion dynamics. With the experimentally determined pion-baryon-baryon coupling const

N. S. Ananikian, R. R. Lusiniants, K. A. Oganessyan

The Feigenbaum constants $α$ and $δ$ for the three-site antiferromagnetic Ising spin model on Husimi tree are calculated. It is shown that the numerical values of these constants for this real physical system coincide with the famous universal Feigenbaum constants with high accuracy. The quantitative description from ordering to chaos is also obtained.

A. S. Cattaneo, P. Cotta-Ramusino, M. Martellini

We study 3-dimensional BF theories and define observables related to knots and links. The quantum expectation values of these observables give the coefficients of the Alexander-Conway polynomial.

S. Penati, D. Zanon

We consider a class of non-unitary Toda theories based on the Lie superalgebras $A^{(1)}(n,n)$ in two-dimensional Minkowski spacetime, which can be twisted into a topological sector. In particular we study the simplest example with $n=1$ and real fields, and show how this theory can be treated as an integrable perturbation of the $A(1,0)$ superconformal mode

R. Blumenhagen, R. Huebel

We investigate the representation theory of some recently constructed N=2 super W-algebras with two generators. Except for the central charges in the unitary minimal series of the N=2 super Virasoro algebra we find no new rational models. However, from our results it is possible to arrange all known N=2 super W-algebras with two generators and vanishing self

R. L. Mkrtchyan

The algebra of volume-preserving vector fields is considered. The potentials for that fields are introduced, and induced algebra of potentials is considered. It is shown, that this algebra fails to satisfy the Jacoby identity. Analogy with hamiltonian mechanics is developed, as well as 3-cocycle interpretation of corresponding expressions.

M. Kibler, C. Campigotto, Yu. F. Smirnov

We report in this article three- and four-term recursion relations for Clebsch-Gordan coefficients of the quantum algebras $U_q(su_2)$ and $U_q(su_{1,1})$. These relations were obtained by exploiting the complementarity of three quantum algebras in a $q$-deformation of $sp(8, \gr)$.

R. Brustein, M. Faux, B. Ovrut

We present a summary of the results of an explicit calculation of the strength of non-perturbative interactions in matrix models and string effective Lagrangians. These interactions are induced by single eigenvalue instantons in the $d=1$ bosonic matrix model. A well defined approximation scheme is used to obtain induced operators whose exact form we exhibit

Robert A. Weston, A. H. Bougourzi

We perform a spectral decomposition of the dynamical correlation function of the spin $1/2$ XXZ model into an infinite sum of products of form factors. Beneath the four-particle threshold in momentum space the only non-zero contributions to this sum are the two-particle term and the trivial vacuum term. We calculate the two-particle term by making use of the

John Ellis, Marek Karliner

New data on polarized $μ-p$ and $e-p$ scattering permit a first determination of $α_s$ using the Bjorken sum rule, as well as higher precision in determining the nucleon spin decomposition. Using perturbative QCD calculations to $O(α_s^4)$ for the non-singlet combination of structure functions, we find $α_s(2.5 GeV^2) = 0.375^{+0.062}_{-0.081}$, correspondin

G. Lazarides, C. Panagiotakopoulos

We construct a supersymmetric model based on the semi-simple gauge group $SU(3)_c \times SU(3)_L \times SU(3)_R$ with the relation $tanβ\simeq m_t/m_b$ automatically arising from its structure. The model below a scale $\sim 10^{16}$ GeV gives naturally rise just to the minimal supersymmetric standard model and therefore to the presently favored values for $s

G. Lazarides, C. Panagiotakopoulos

We construct a supersymmetric SO(10) model with the asymptotic relation tan$β\simeq m_t/m_b$ automatically arising from its structure. The model retains the significant Minimal Supersymmetric Standard Model predictions for $sin^2 θ_w$ and $α_s$ and contains an automatic $Z_2$ matter parity. Proton decay through $d=5$ operators is sufficiently suppressed. It

Jeroen C. Vink

The Laplacian gauge on the lattice is investigated numerically using U(1) and SU(2) gauge fields. The problem of Gribov ambiguities is addressed and to asses the smoothness of the gauge fixed configurations, they are compared to configurations fixed to the Landau gauge. The results of these comparisons with the Landau gauge indicate that Laplacian gauge fixi

Wolfhard Janke, Stefan Kappler

Inspired by the multicanonical approach to simulations of first-order phase transitions we propose for $q$-state Potts models a combination of cluster updates with reweighting of the bond configurations in the Fortuin-Kastelein-Swendsen-Wang representation of this model. Numerical tests for the two-dimensional models with $q=7, 10$ and $20$ show that the aut

C. B. Lang, T. Neuhaus

We study the pure gauge model on a lattice manifold with trivial fundamental homotopy group, homotopically equivalent to an $S_4$. Monopole loops may fluctuate freely on that lattice without restrictions due to the boundary conditions. For the original Wilson action on the hypertorus there is an established two-state signal in energy distribution functions w

Daksh Lohia

In theories of gravitation in which dimensional parameters are dynamically induced, one can have non - topological - soliton solutions. This article reviews related topics connected with such solutions. The existence of such solutions in curved spacetime can give rise to halos of gravity (g-) balls with gravitational ``constant" having different values i

Daksh Lohia

The existence of non trivial, non topological solutions in a class of induced, effective gravity models arising out of a non minimally coupled scalar field is established. We shall call such solutions ``Gravity Balls'' as the effective gravitational constant inside the soliton differs from its effective value outside.

Vladimir Cherepanov

Freezing of the classical spin liquid of the Heisenberg kagomé antiferromagnet is studied. At low temperature, the coplanar spin configurations are known to dominate among all possible three-dimensional low-energy states because of the fluctuation interaction. It is shown that the statistical weight of ${\bf q} =0$ domains is negligible. This allows one to d

C. Vermeulen, W. Barford, E. R. Gagliano

The phase diagram of the copper-oxide chain as a function of density and the nearest-neighbour Coulomb interaction, V, is determined. Phase separation takes place above a critical value of $V$ when the Cu2+ to Cu+ valence fluctuations dominate. In the proximity of the phase separation boundary the superconducting correlations are the most divergent. We ident

Francisco Dominguez-Adame, Enrique Diez, Angel Sanchez

We study electronic transport properties of disordered polymers in the presence of both uncorrelated and short-range correlated impurities. In our procedure, the actual physical potential acting upon the electrons is replaced by a set of nonlocal separable potentials, leading to a Schrödinger equation that is exactly solvable in the momentum representation.

W. Barford, M. W. Long

We consider the effect of the nearest neighbour copper-oxygen repulsion, V, when coupled to the charge transfer resonances Cu2+ to Cu3+ and Cu2+ to Cu+ in the high temperature cuprate superconductors. This is done by deriving effective low energy Hamiltonians correct to second order in the copper-oxygen hybridisation. Only hole doping is considered. When Cu2

C. Vermeulen, W. Barford, E. R. Gagliano

The phase diagram of the copper-oxide chain as a function of density and the nearest-neighbour Coulomb interaction, V, is determined. Phase separation takes place above a critical value of $V$ when the Cu2+ to Cu+ valence fluctuations dominate. In the proximity of the phase separation boundary the superconducting correlations are the most divergent. We ident

G. Giugliarelli, A. L. Stella

We study a $d=2$ discrete solid--on--solid model of complete wetting of a rough substrate with random self--affine boundary, having roughness exponent $ζ_s$. A suitable transfer matrix approach allows to discuss adsorption isotherms, as well as geometrical and thermal fluctuations of the interface. For $ζ_s\leq 1/2$ the same wetting exponent $ψ=1/3$ as for f

Jorge V. José, Cristian Rojas

We study the competition between Josephson and charging energies in two-dimensional arrays of ultrasmall Josephson junctions, when the mutual capacitance is dominant over the self-capacitance. Our calculations involve a combination of an analytic WKB renormalization group approach plus nonperturbative Quantum Monte Carlo simulations. We consider the zero fru

D. F. B. ten Haaf, P. W. Brouwer, P. J. H. Denteneer, J. M. J. van Leeuwen

We derive low-temperature properties of the large-U Hubbard model in two and three dimensions from exact series-expansion results for high temperatures. Convergence problems and limited available information prevent a direct or Pade'-type extrapolation. We propose a new method of extrapolation, which is restricted to large U and low hole densities, for w

Nora Menyhárd

Nonequilibrium kinetic Ising models evolving under the competing effect of spin flips at zero temperature and nearest neighbour spin exchanges at $T=\infty$ are investigated numerically from the point of view of a phase transition. Branching annihilating random walk of the ferromagnetic domain boundaries determines the steady state of the system for a range

Jean DESBOIS, Christine HEINEMANN, Stéphane OUVRY

The computation of the $N$-cycle brownian paths contribution $F_N(α)$ to the $N$-anyon partition function is adressed. A detailed numerical analysis based on random walk on a lattice indicates that $F_N^{(0)}(α)= \prod_{k=1}^{N-1}(1-{N\over k}α)$. In the paramount $3$-anyon case, one can show that $F_3(α)$ is built by linear states belonging to the bosonic,

Imre Varga, Etienne Hofstetter, Michael Schreiber, János Pipek

We present a new method for the numerical treatment of second order phase transitions using the level spacing distribution function $P(s)$. We show that the quantities introduced originally for the shape analysis of eigenvectors can be properly applied for the description of the eigenvalues as well. The position of the metal--insulator transition (MIT) of th

Craig J. Hogan

The observed cosmic abundances of light elements are most consistent with each other, and with the predictions of big bang nucleosynthesis,if, contrary to the usual assumption, galactic chemical evolution reduces $(D+\ ^3He)/H$ with time. Chemical evolution models which do this require that low mass stars destroy $^3He$ in the envelope gas that they return t

J. W. Moffat, D. C. Tatarski

A local void in the globally Friedmann-Robertson-Walker (FRW) cosmological model is studied. The inhomogeneity is described using the Lema\^ıtre-Tolman-Bondi (LTB) solution with the spherically symmetric matter distribution based on the faint galaxies number counts. We investigate the effects this has on the measurement of the Hubble constant and the redshif

A. Buium, J. F. Voloch

For an abelian variety $A$ over a function field $K$ of characteristic zero, Manin defined a remarkable additive map $A(K) \ra V$, where $V$ is a vector space over $K$. We define an analogue of this map in the case of function fields of characteristic $p$. We then prove that the reduction modulo $p$ of the Manin map in characteristic zero is the derivative o

K. Tsushima, S. W. Huang, Amand Faessler

The long mean free path of $K^+$ mesons in nuclear matter makes this particle a suitable messenger for the dynamics of nucleus-nucleus reactions at intermediate energies (100 MeV to 3 GeV per nucleon). A prerequisite for this is the knowledge of the elementary production cross sections $πN \rightarrow ΣK$. Here these cross sections are studied for the first

Yu. I. Manin

We calculate generating functions for the Poincare polynomials of moduli spaces of pointed curves of genus zero and of Configuration Spaces of Fulton and MacPherson. We also prove that contributions of multiple coverings of curves in a Calabi-Yau threefold calculated via Kontsevich's compactification coincide with the prediction of Candelas et al., and A

K. Tsushima, S. W. Huang, Amand Faessler

The elementary production cross sections $πΔ\rightarrow Y K$ $(Y=Σ,\,\, Λ)$ and $πN \rightarrow Y K$ are needed to describe kaon production in heavy ion collisions. The $πN \rightarrow Y K$ reactions were studied previously by a resonance model. The model can explain the experimental data quite well \cite{tsu}. In this article, the total cross sections $πΔ\r

R. G. Mints, I. B. Snapiro

We consider the Josephson vortex motion in a long one--dimensional Josephson junction in a thin film. We show that this Josephson vortex is similar to a mesoscopic capacitor. We demonstrate that a single Cooper pair tunneling results in nonlinear Bloch--type oscillations of a Josephson vortex in a current-biased Josephson junction. We find the frequency and

Jorge G. Hirsch, O. Castaños, P. O. Hess

The zero neutrino mode of the double beta decay in heavy deformed nuclei is investigated in the framework of the pseudo SU(3) model, which has provided an accurate description of collective nuclear structure and predicted half-lives for the two neutrino mode in good agreement with experiments. In the case of $^{238}U$ the calculated zero neutrino half-life i

Andreas Blass

We discuss two general aspects of the theory of cardinal characteristics of the continuum, especially of proofs of inequalities between such characteristics. The first aspect is to express the essential content of these proofs in a way that makes sense even in models where the inequalities hold trivially (e.g., because the continuum hypothesis holds). For th

Daniel Lieman

This paper surveys the connection between the elliptic curve E_D: x^3 + y^3 = D and a certain metaplectic form on the cubic cover of GL(3) which has the property that its m,n^{th} Whittaker--Fourier coefficient is essentially the L--series of the curve E_{m^2n}. One may obtain information about the collective behavior the curves E_D by exploiting this connec

Friedemann Brandt, Walter Troost, Antoine Van Proeyen

We present results of a computation of the BRST-antibracket cohomology in the space of local functionals of the fields and antifields for a class of 2d gravitational theories which are conformally invariant at the classical level. In particular all classical local action functionals, all candidate anomalies and all BRST--invariant functionals depending nontr

A. J. Niemi, V. V. Sreedhar

We investigate a modification of the 2+1 dimensional abelian Chern-Simons theory, obtained by adding a Proca mass term to the gauge field. We are particularly interested in the infrared limit, which can be described by two {\it a priori} different "topological" quantum mechanical models. We apply methods of equivariant cohomology and the ensuing supe

G. Jorjadze L. O'Raifeartaigh I. Tsutsui

A quantum theory is constructed for the system of a relativistic particle with mass m moving freely on the SL(2,R) group manifold. Applied to the cotangent bundle of SL(2,R), the method of Hamiltonian reduction allows us to split the reduced system into two coadjoint orbits of the group. We find that the Hilbert space consists of states given by the discrete

Yoshiyuki Watabiki

We study the non-critical string field theory with non-orientable string interactions by using the transfer matrix formalism in the dynamical triangulation. For any value of $c$ (total central charge of matter), we have constructed the non-orientable string field theory at the discrete level. Two coupling constants $G$ and $\Gx$ which satisfy the relation $(

Ashok Das, Marcelo Hott

In this short note, we indicate the origin of nonanalyticity in the method of derivative expansion at finite temperature and discuss some of its consequences.

S. Voloshin, Y. Zhang

We propose a new method to study transverse flow effects in relativistic nuclear collisions by Fourier analysis of the azimuthal distribution on an event-by-event basis in relatively narrow rapidity windows. The distributions of Fourier coefficients provide direct information on the magnitude and type of flow. Directivity and two dimensional sphericity tenso

D. Matalliotakis, H. P. Nilles

We give a short introduction to the concept of low energy supersymmetric models and their phenomenological predictions. In view of the future LEP II results we have to parametrize these predictions in a model independent way without too many simplifying assumptions. The study must therefore include models with {\it non--universal} soft supersymmetry breaking

Sergei Voloshin

A method for an evaluation of fluctuations in the mixed event technique is proposed. It is shown, that, generally, the magnitude of the fluctuations is proportional to $N^{3/4}$, where $N$ is the number of produced events, which should be compared with $N^{1/2}$ for the case of independent events. The formula eligible for the use in an analysis of experiment

D. Kalafatis

In this talk I concentrate on the role of chiral symmetry realisation by spin-1 fields in the low energy QCD effective lagrangian. I assume that chiral symmetry is nonlinearly realised and that spin-1 fields transform homogeneously under chiral rotations, which is in sharp contrast to previous works where the $ρ$ and the $a_1$ mesons were treated as approxim

F. Buccella, O. Pisanti, F. Sannino

We relate the asymmetries in the charged pions energy in the decay into $π^+π^-π^0$ of $K_L$ and of the tagged neutral kaons. The former asymmetry is a given combination of $\Re(ε)$, $\Im(ε)$, and $|ε'|$. Moreover, the non-violating CP asymmetry allows a test for the $χ$PT predictions within the Zel'dovich approach for the final state interaction.

Marc Baillargeon, Paula Franzini

We estimate the experimental accuracies to which the Ke4 parameters will be measured at DAPHNE. We consider the accuracies obtainable using asymmetries, and the maximum likelihood method. We find the current determinations of the relevant parameters will be improved by a factor of five to ten after a year of running at the anticipated luminosity of DAPHNE.

Stefan Pokorski

We summarize the expectations for the top quark mass in supersymmetric models and discuss the potential implications of its value measured by the CDF group in Fermilab.

S. V. Goloskokov, O. V. Selyugin

The spin effects in nucleon-nucleon scattering are calculated in the framework of the dynamic model taking into account interactions at large distances and the strong form factors; the model factorization of the $NN$ amplitude into the spin-dependent hadron-pomeron vertex and high-energy spinless pomeron is obtained. Theoretical predictions for polarization

L. L. Frankfurt, G. A. Miller, M. Strikman

CONTENTS. 1.Introduction, 1.1 QCD ideas to be tested; 2. Coherence phenomena in QED, 2.1 Charge transparency, 2.2 Charge filtering, 2.3 Charge opacity; 3. Color transparency in perturbative QCD, 3.1 Coherence length in QCD, 3.2 Bjorken scaling for deep inelastic processes, 3.3 Hard Coherent Diffraction {}From Nucleons and Nuclei; 4. Soft Diffractive Physics

Stuart Boersma, Tevian Dray

A parametric manifold is a manifold on which all tensor fields depend on an additional parameter, such as time, together with a parametric structure, namely a given (parametric) 1-form field. Such a manifold admits natural generalizations of Lie differentiation, exterior differentiation, and covariant differentiation, all based on a nonstandard action of vec

Stuart Boersma, Tevian Dray

A parametric manifold can be viewed as the manifold of orbits of a (regular) foliation of a manifold by means of a family of curves. If the foliation is hypersurface orthogonal, the parametric manifold is equivalent to the 1-parameter family of hypersurfaces orthogonal to the curves, each of which inherits a metric and connection from the original manifold v

Philip D. Mannheim

We review the current status and prospects for the conformal invariant fourth order theory of gravity which has recently been advanced by Mannheim and Kazanas as a candidate alternative to the standard second order Einstein theory. We examine how it is possible in principle to replace the Einstein theory at all while retaining its tested features, and we app

Othmar Brodbeck, Norbert Straumann

We prove that static, spherically symmetric, asymptotically flat, regular solutions of the Einstein-Yang-Mills equations are unstable for arbitrary gauge groups, at least for the ``generic" case. This conclusion is derived without explicit knowledge of the possible equilibrium solutions.

Jysoo Lee, Joel Koplik

As a first step in the first passage problem for passive tracer in stratified porous media, we consider the case of a two-dimensional system consisting of two layers with different convection velocities. Using a lattice generating function formalism and a variety of analytic and numerical techniques, we calculate the asymptotic behavior of the first passage

Wolfdieter Lang

Fibonacci chains are special diatomic, harmonic chains with uniform nearest neighbour interaction and two kinds of atoms (mass-ratio $r$) arranged according to the self-similar binary Fibonacci sequence $ABAABABA...$, which is obtained by repeated substitution of $A \to AB$ and $B \to A$. The implications of the self-similarity of this sequence for the assoc

R. J. Bursill

In this paper we study the thermodynamics of the one dimensional continuum analogue of the Falicov-Kimball model in the strongly correlated limit using a method developed by Salsburg, Zwanzig and Kirkwood for the Takahashi gas. In the ground state it is found that the $f$ electrons form a cluster. The effect of including a Takahashi repulsion between $f$ par

Giulia Galli, Francesco Mauri

We present tight binding molecular dynamics simulations of C_60 collisions on the reconstructed diamond(111) surface, carried out with an O(N) method and with cells containing 1140 atoms. The results of our simulations are in very good agreement with experiments performed under the same impact conditions. Furthermore our calculations provide a detailed chara

Nobuo Furukawa

The Kondo lattice model with Hund's ferromagnetic spin coupling is investigated as a microscopic model of the perovskite-type 3d transition-metal oxide La$_{1-x}$Sr$_x$MnO$_3$. In the classical spin limit $S=\infty$ and the infinite-dimensional limit $D=\infty$, the one-body Green's function is calculated exactly. Transport properties of the system i

Ronald Dickman

A numerical method is devised for study of stochastic partial differential equations describing directed percolation, the contact process, and other models with a continuous transition to an absorbing state. Owing to the heightened sensitivity to fluctuationsattending multiplicative noise in the vicinity of an absorbing state, a useful method requires discre

F. C. Alcaraz, A. L. Malvezzi

The phase diagram of the $XXZ$ chain under the influence of homogeneous and staggered magnetic fields is calculated. The model has a rich phase structure with three types of phases. A fully ferromagnetic phase, an antiferromagnetic phase and a massless phase with partial ferromagnetic and antiferromagnetic order. This massless phase has its critical fluctuat

Manny Rayner, David Carter, Vassilios Digalakis, Patti Price

A simple and general method is described that can combine different knowledge sources to reorder N-best lists of hypotheses produced by a speech recognizer. The method is automatically trainable, acquiring information from both positive and negative examples. Experiments are described in which it was tested on a 1000-utterance sample of unseen ATIS data.

Manny Rayner, David Carter, Patti Price, Bertil Lyberg

Most spoken language translation systems developed to date rely on a pipelined architecture, in which the main stages are speech recognition, linguistic analysis, transfer, generation and speech synthesis. When making projections of error rates for systems of this kind, it is natural to assume that the error rates for the individual components are independen

K. Jedamzik, G. J. Mathews, G. M. Fuller

We show that a class of inhomogeneous big bang nucleosynthesis models exist which yield light-element abundances in agreement with observational constraints for baryon-to-photon ratios significantly smaller than those inferred from standard homogeneous big bang nucleosynthesis (HBBN). These inhomogeneous nucleosynthesis models are characterized by a bimodal

G. M. Fuller, K. Jedamzik, G. J. Mathews, A. Olinto

Primordial nucleosynthesis calculations are shown to be able to provide constraints on electroweak baryogenesis which produce a highly inhomogeneous distribution of the baryon-to-photon ratio. Such baryogenesis scenarios overproduce 4He and/or 7Li and can be ruled out whenever a fraction f<3*10e-6(100 GeV/T)^3 of nucleated bubbles of broken-symmetry phase co

G. Yepes, A. Klypin, A. Campos, R. Fong

We estimate the angular correlation function for the standard CDM, tilted $n=0.7$ CDM and hybrid (CHDM) models, and compare with observations. When compared with the APM observational results scaled to the Lick depth, there appears to be fair agreement with the estimate from the CHDM model. But a more detailed comparison using the unscaled APM data for the f

Peter Schneider, Carolin Seitz

The distortion of images of faint, high-redshift galaxies by light deflection at foreground clusters of galaxies can be used to determine the (projected) mass distribution of the clusters. In the case of strong distortions, which lead to arcs in clusters, the position of the arc and/or its radius of curvature yields an estimate for the total mass inside a ci

D. A. Frail, W. M. Goss, J. B. Z. Whiteoak

We have made VLA images of the fields around three young pulsars which have resulted in the discovery of two new supernova remnants and confirmation of a third. We argue that, in at least two cases and perhaps the third, the pulsars are physically associated with these supernova remnants. A review of all known young pulsars shows that the majority are associ

Nguyen Ai Viet

An unified structure of noncommutative space-time for both gravity and particle physics is presented. This gives possibilities of testing the idea of noncommutative space-time at the currently available energy scale. There are several arguments indicating that noncommutative space-time is visible already at the electroweak scale. This noncommutative space-ti

Robert J. Perry

Light-front coordinates offer a scenario in which a constituent picture of hadron structure can emerge from QCD, after several difficulties are addressed. Field theoretic difficulties force us to introduce cutoffs that violate Lorentz covariance and gauge invariance, and a new renormalization group formalism based on a similarity transformation is used with

J. David Brown

The connection is established between two different action principles for perfect fluids in the context of general relativity. For one of these actions, $S$, the fluid four--velocity is expressed as a sum of products of scalar fields and their gradients (the velocity--potential representation). For the other action, ${\bar S}$, the fluid four--velocity is pr

C. N. Lovett-Turner, C. J. Maxwell

We explicitly determine the residues and orders of all the ultra-violet (UV) and infra-red (IR) renormalon poles in the Borel plane for the QCD vacuum polarization function (Adler D-function), to leading order in an expansion in the number of quark flavours, $N_{f}$. The singularity structure is precisely as anticipated on general grounds. In particular, the

Arif Akhundov, Dima Bardin, Lida Kalinovskaya, Tord Riemann

We give an exhaustive presentation of the semi-analytical approach to the model independent leptonic QED corrections to deep inelastic neutral current lepton-nucleon scattering. These corrections include photonic bremsstrahlung from and vertex corrections to the lepton current of the order ${\cal O}(α)$ with soft photon exponentiation. % A common treatment o

Hiroshi Kunitomo

The nonlinear realization of the superconformal symmetry in two dimensions is considered. The superconformal symmetry is realized by means of dimension $-1/2$\ Nambu-Goldstone fermion $ξ$\ and its dimension 3/2 conjugate $η$. A matter coupling of these Nambu- Goldstone fermions reproduce the realization found by Berkovits and Vafa to show the equivalence bet

Victor G. Kac, Minoru Wakimoto

In the first part of the paper we give the denominator identity for all simple finite-dimensional Lie super algebras $\frak g\/$ with a non-degenerate invariant bilinear form. We give also a character and (super) dimension formulas for all finite-dimensional irreducible $\frak g\/$-modules of atypicality $\leq 1\/$ . In the second part of the paper we give t

Terry Gannon, Mark A. Walton

We relate in a novel way the modular matrices of GKO diagonal cosets without fixed points to those of WZNW tensor products. Using this we classify all modular invariant partition functions of $su(3)_k\oplus su(3)_1/su(3)_{k+1}$ for all positive integer level $k$, and $su(2)_k\oplus su(2)_\ell/su(2)_{k+\ell}$ for all $k$ and infinitely many $\ell$ (in fact, f

R. Barbier, J. Meyer, M. Kibler

A rotational model is developed from a new version of the two-parameter quantum algebra $U_{qp}({\rm u}_2)$. This model is applied to the description of some recent experimental data for the rotating superdeformed nuclei $^{192-194-196-198}{\rm Pb}$ and $^{192-194 }{\rm Hg}$. A comparison between the $U_{qp}({\rm u}_2)$ model presented here and the Raychev-R

Bo-Yu Hou, Bo-Yuan Hou, Zhong-Qi Ma

In this paper, we introduce an $N\times N$ matrix $ε^{a\bar{b}}$ in the quantum groups $SU_{q}(N)$ to transform the conjugate representation into the standard form so that we are able to compute the explicit forms of the important quantities in the bicovariant differential calculus on $SU_{q}(N)$, such as the $q$-deformed structure constant ${\bf C}_{IJ}^{~K

V. Barger, M. S. Berger, P. Ohmann, R. J. N. Phillips

The top-quark Yukawa infrared fixed-point solution of the renormalization group equations, with minimal supersymmetry and GUT unification, defines a low-energy spectrum of supersymmetric particle masses in terms of a few GUT-scale parameters assuming universal boundary conditions. We give predictions in this model for the inclusive $b\to sγ$ branching fracti

S. Liuti, R. Vogt

We study nuclear shadowing in $J/ψ$ and $Υ$ production in hadron-nucleus interactions and in nucleus-nucleus collisions at the Relativistic Heavy Ion Collider and the Large Hadron Collider. %We define the regions in $x_f$ where nuclear shadowing begins %to set in for \jp\ and \up. As a consequence of the perturbative $Q^2$-dependence of gluon shadowing, we p

K. G. Chetyrkin, J. H. Kühn, A. Kwiatkowski

Radiative QCD corrections significantly influence the theoretical predictions for the decay rates of the $Z$ and the Higgs boson. The status of the QCD calculations to the hadronic $Z$ width is reviewed. The role of mass corrections from bottom quark final states is emphasized. An estimate of the theoretical uncertainties is given. New results for quartic ma

V. Gribov

In this short note I present a simple calculation of the top quark and Higgs masses, based on the idea that in the standard model without elementary Higgs, the fact that the $U(1)_Y$ coupling becomes of the order of unity at the Landau scale $λ$ leads to spontaneous symmetry breaking and generation of masses.

D. Litim, C. Wetterich, N. Tetradis

We perform a non-perturbative study of the Coleman-Weinberg phase transition in scalar QED. Our method permits a consistent treatment of the effective potential near the origin, a region not accessible to perturbation theory. As a result, we establish reliably the first order character of the phase transition for arbitrary values of the scalar coupling.

Zurab G. Berezhiani, Anna Rossi

It is well known that the matter can significantly alter the picture of neutrino oscillation \cite{W} or neutrino decay \cite{BV}. Here we show that the presence of dense matter induces also the decay of {\it massless} majoron, a Goldstone boson associated with the spontaneous lepton number violation, into a couple of neutrinos with the same (or in some case

Zurab G. Berezhiani

We present a new predictive approach based on SUSY $SO(10)$ theory. The inter-family hierarchy is first generated in the sector of hypothetical superheavy fermions and then transfered inversely to ordinary quarks and leptons by means of the universal seesaw mechanism. The obtained mass matrices are simply parametrized by two small complex coefficients $\eps_

M. Sadzikowski

Using the (modified) MIT bag model we calculated formfactors and decay widths for pseudoscalar - pseudoscalar and pseudoscalar - vector semileptonic decays of heavy to light mesons. We discuss the physical phenomena which are important in these processes and their influence on the measurable quantities. Our results are consistent with the available experimen

Dominik J. Schwarz

All regular and singular cosmological perturbations in a radiation dominated Einstein-de Sitter Universe with collisionless particles can be found by a generalized power series ansatz. Talk given at &#34;Birth of the Universe and Fundamental Physics&#34;, May 1994 (Rome).

Daniel Domínguez, Jorge V. José

This is a review of recent work on the dynamic response of Josephson junction arrays driven by dc and ac currents. The arrays are modeled by the resistively shunted Josephson junction model, appropriate for proximity effect junctions, including self-induced magnetic fields as well as disorder. The relevance of the self-induced fields is measured as a functio

R. D. Parmentier

Discrete arrays of Josephson junction elements differ from their continuum counterparts in two essential ways: i) localized dynamic states in discrete arrays, which are not present in the corresponding continuum system, can interact with other excitations that are present; ii) fluxoid quantization for the non-superconducting `holes&#39; provides a constraint

A. D. Bolatto, E. E. Falco

We discuss a possible method for detection of dark companions of galactic objects of stellar mass. Such binary systems are likely to occur in the galactic disk and possibly also in the halo. The high incidence of binary and higher-multiplicity systems in the solar neighborhood, if indicative of the galactic disk at large, implies that current searches for th

David F. Crawford

In principle the geometry of the universe can be investigated by measuring the angular size of known objects as a function of distance. Thus the distribution of angular sizes provides a critical test of the stable and static model of the universe described by Crawford (1991,1993) that has a simple and explicit relationship between the angular size of an obje

David F. Crawford

A crucial test of any cosmological model is the distribution of distant objects such as quasars. Because of well defined selection criteria quasars found by a ultraviolet excess (UVX) survey are ideal candidates for testing the model out to a redshift of z = 2.2. The static cosmology proposed by Crawford (1993) is used to analyse a recent quasar survey (BOYL

T. Becker, H. de Vries, B. Eckhardt

We analyze in detail a one-dimensional stochastically driven running sandpile. The dynamics shows three different phases, depending on the on-site relaxation rate and stochastic driving rate. Two phases are characterized by the presence of travelling waves. The third shows algebraic relaxation.