October 1994 arXiv papers — page 4

C. R. Hagen

A recent suggestion has been made that the hydrogen bound state spectrum should not depend on the number of spatial dimensions. It is pointed out here that the uncertainty principle implies that such differences must exist and that a perturbation expansion in the dimensionality parameter yields a precise quantitative confirmation of the effect.

K. Sveshnikov

It is shown, that extended particle-like objects should infinitely long collapse into some discontinuous configurations of the same topology, but vanishing mass. Analytic results concerning the general properties and asymptotic rates of such a process are given for 1+1-dimensional soliton models.

A. J. Gill, R. J. Rivers

Our understanding of the mechanism by which topological defects are formed in symmetry breaking phase transitions has recently changed. We examine the non-equilibrium dynamics of defect formation for weakly-coupled global O(N) theories possessing vortices (strings) and monopoles. It is seen that, as domains form and grow, defects are swept along on their bou

Amihay Hanany, Yaron Oz

The discrete states of $c=1$ string theory at the self-dual radius are associated with modes of $W_{1+\infty}$ currents and their genus zero correlators are computed. An analogy to a recent suggestion based on the integrable structure of the theory is found. An iterative method for deriving the dependence of the currents on the full space of couplings is pre

Wen-Jui Huang, J. C. Shaw, H. C. Yen

We examine the conformal property of the second Hamiltonian structure of constrained KP hierarchy derived by Oevel and Strampp. We find that it naturallygives a family of nonlocal extended conformal algebras. We give two examples of such algebras and find that they are similar to Bilal's V algebra. By taking a gauge transformation one can map the constra

Tze-Dan Chung

By analytically continuing the time variable in a black hole background, and requiring unitary evolution, it is found that quantum mechanical states at the horizon develop a thermal factor under suitable identification of the physical time. The thermal factor is found to be determined exactly by the Hawking's temperature. This can be interpreted as the H

S. Mallik

It is shown that the chiral nonanalytic terms generated by $Δ_{33}$ resonance in the nucleon self-energy is reproduced in chiral perturbation theory by perturbing appropriate local operators contained in the pion-nucleon effective Lagrangian itself.

L. Clavelli

We discuss the anomaly in the $b$ branching ratio of the $Z$ in the context of the light gluino scenario.

Katri Huitu, Jukka Maalampi

We study the symmetry breaking sector of a supersymmetric left-right model based on the gauge group $SU(2)_L\times SU(2)_R\times U(1)_{B-L}$. The explicit mass matrices of neutral, singly charged and doubly charged scalars are constructed. In the minimum the $R$-parity is found to be spontaneously broken. An experimentally interesting feature of the model is

Vittorio Del Duca, Carl R. Schmidt

In this contribution we examine the transverse momentum distributions in dijet production at large rapidity intervals at the Tevatron, using the BFKL resummation.

R. Ugoccioni, A. Giovannini, S. Lupia

It is shown that the ratio of factorial cumulant moments to factorial moments for a multiplicity distribution truncated in the tail reveals oscillations in sign similar to those observed in experimental data. It is suggested that this effect be taken into account in the analysis of data in order to obtain correct physical information on the multiplicity dist

C. R. Allton

We present an analysis of the continuum extrapolation of $f_B$ in the static approximation from lattice data. The method described here aims to uncover the systematic effects which enter in this extrapolation and has not been described before. Our conclusions are that we see statistical evidence for scaling of $f_B^{stat}$ for inverse lattice spacings $\gtap

I. Montvay

The N=2 supersymmetric Yang-Mills theory is formulated on the lattice. The feasibility of numerical simulations is discussed.

U. Kasper, S. Kluske, M. Rainer, S. Reuter

We discuss the instabilities appearing in the cosmological model with a quasi de Sitter phase following from a fourth-order gravity theory. Both the classical equation as well as the quantization in form of a Wheeler - De Witt equation are conformally related to the analogous model with Einstein's theory of gravity with a minimally coupled scalar field.

D. Giulini, C. Kiefer, H. D. Zeh

We discuss the applicability of the programme of decoherence -- emergence of approximate classical behaviour through interaction with the environment -- to cases where it was suggested that the presence of symmetries would lead to exact superselection rules. For this discussion it is useful to make a distinction between pure symmetries and redundancies, whic

A. Kadigrobov, A. Zagoskin, R. I. Shekhter, M. Jonson

A theoretical explanation of giant conductance oscillations observed in normal mesoscopic rings with superconducting ``mirrors" is proposed. The effect is due to resonant tuning of Andreev levels to the Fermi level, which enhances the transparency of the system to the normal current. The mechanism is demonstrated for a one-dimensional model system.

B. Srinivas, Dania Egedi, Christy Doran, Tilman Becker

In this paper we present a fully lexicalized grammar formalism as a particularly attractive framework for the specification of natural language grammars. We discuss in detail Feature-based, Lexicalized Tree Adjoining Grammars (FB-LTAGs), a representative of the class of lexicalized grammars. We illustrate the advantages of lexicalized grammars in various con

Dania Egedi, Patrick Martin

This paper presents a syntactic lexicon for English that was originally derived from the Oxford Advanced Learner's Dictionary and the Oxford Dictionary of Current Idiomatic English, and then modified and augmented by hand. There are more than 37,000 syntactic entries from all 8 parts of speech. An X-windows based tool is available for maintaining the lex

David Elworthy

A technique for detecting errors made by Hidden Markov Model taggers is described, based on comparing observable values of the tagging process with a threshold. The resulting approach allows the accuracy of the tagger to be improved by accepting a lower efficiency, defined as the proportion of words which are tagged. Empirical observations are presented whic

Hans Karlgren, Jussi Karlgren, Magnus Nordström, Paul Pettersson

Dilemma is intended to enhance quality and increase productivity of expert human translators by presenting to the writer relevant lexical information mechanically extracted from comparable existing translations, thus replacing - or compensating for the absence of - a lexicographer and stand-by terminologist rather than the translator. Using statistics and cr

L. Tresse, C. Rola, F. Hammer, G. Stasinska

We present the first detailed spectroscopic study of field galaxies up to z=0.3 from the I-magnitude limited CFRS sample. In this complete sample, we find that about half of the objects are blue emission-line galaxies. Using line ratio diagram and photoionization models, we show that in roughly half of these emission-line galaxies, ionization by hot stars ca

Atsushi Moriwaki

In this short note, we will gives several remarks on rational points of varieties whose cotangent bundles are generated by global sections. For example, we will show that if the sheaf of differentials of a projective variety X over a number field k is ample and generated by global sections, then the set of k-rational points of X is finite.

S. Brivio, A. Verra

Let $X$ be the moduli space of semistable rank 2 vector bundles over a smooth curve C of genus $g \ge 2$ and $θ: X \to PH^0(L)^*$ be the map associated to the generalized theta divisor L on X. We prove that for C not hyperelliptic, the map $θ$ is injective and the differential of $θ$ is injective at smooth points of X.

G. S. Kanner, J. Tinka Gammel, S. P. Love, S. R. Johnson

We report the pressure dependence up to 95 kbar of Raman active stretching modes in the quasi-one-dimensional MX chain solid $Pt_2Br_6(NH_3)_4$. The data indicate that a predicted pressure-induced insulator-to-metal transition does not occur, but are consistent with the solid undergoing either a three-dimensional structural distortion, or a transition from a

Hugo Garcia-Compean, Laura E. Morales, Jerzy F. Plebanski

The two-dimensional non-linear sigma model approach to Self-dual Yang-Mills theory and to Self-dual gravity given by Q-Han Park is an example of the deep interplay between two and four dimensional physics. In particular, Husain's two-dimensional chiral model approach to Self-dual gravity is studied. We show that the infinite hierarchy of conservation law

Paul P. Budnik

Franson showed that Aspect's experiment to test Bell's inequality did not rule out local realistic theories with delayed determinism. A class of local, deterministic discrete mathematical models with delayed determinism is described that may be consistent with existing experiments. These are not hidden variables theories in the sense that they are no

A. Denner, S. Dittmaier, G. Weiglein

Application of the background-field method yields a gauge-invariant effective action for the electroweak Standard Model, from which simple QED-like Ward identities are derived. As a consequence of these Ward identities, the background-field Green functions are shown to possess very desirable theoretical properties. The renormalization of the Standard Model i

T. Blum, Steven Gottlieb, Leo Karkkainen, D. Toussaint

We measure the pressure and energy density of two flavor QCD in a wide range of quark masses and temperatures. The pressure is obtained from an integral over the average plaquette or psi-bar-psi. We measure the QCD beta function, including the anomalous dimension of the quark mass, in new Monte Carlo simulations and from results in the literature. We use it

A. D. Rutenberg, A. J. Bray

The one-dimensional $O(2)$ model is the simplest example of a system with topological textures. The model exhibits anomalous ordering dynamics due to the appearance of two characteristic length scales: the phase coherence length, $L \sim t^{1/z}$, and the phase winding length, $L_{w} \sim L^χ$. We derive the scaling law $z=2+μχ$, where $μ=0$ ($μ=2$) for nonc

M. R-Monteiro, I. Roditi, L. M. C. S. Rodrigues, S. Sciuto

We consider the Quantum Inverse Scattering Method with a new R-matrix depending on two parameters $q$ and $t$. We find that the underlying algebraic structure is the two-parameter deformed algebra $SU_{q,t}(2)$ enlarged by introducing an element belonging to the centre. The corresponding Hamiltonian describes the spin-1/2 XXZ model with twisted periodic boun

P. Marenzoni, G. Martinelli, N. Stella

We present the results of a high statistics lattice study of the gluon propagator, in the Landau gauge, at $β=6.0$. As suggested by previous studies, we find that, in momentum space, the propagator is well described by the expression $G(k^2)= \Big[ M^2 + Z\cdot k^2(k^2/Λ^2)^η\Big]^{-1} $. By comparing $G(k^2)$ on different volumes, we obtain a precise determ

A. Datta, S. Chakravarti, M. Guchait

Relatively light sneutrinos which are experimentally allowed and are not theoretically disfavoured may significantly affect the currently popular search strategies for supersymmetric particles by decaying dominantly into an invisible channel. In certain cases the second lightest neutralino may also decay invisibly leading to two extra carriers of missing ene

B. Siebert, G. Tian

The authors learnt that similar results have been independently found by D.Zagier, V.Baranovsky and V.Balaji/A.King/P.Newstead. The corresponding references have been added (and some typos corrected).

M. M. Sharma, G. A. Lalazissis, J. Koenig, P. Ring

The isospin dependence of the spin-orbit potential is investigated for an effective Skyrme like energy-functional suitable for density-dependent Hartree-Fock calculations. The magnitude of the isospin dependence is obtained from a fit to experimental data on finite spherical nuclei. It is found to be close to that of relativistic Hartree models. Consequently

Daniel Bump, Solomon Friedberg, Masaaki Furusawa

In this paper we will study certain models of irreducible admissible representations of the split special orthogonal group $SO(2n+1)$ over a nonarchimedean local field. If $n=1$, these models were considered by Waldspurger. If $n=2$, they were considered by Novodvorsky and Piatetski-Shapiro \cite{NP}, who called them {\it Bessel models}. They arise from a va

E. D'Hoker, D. H. Phong

In theories of closed oriented superstrings, the one loop amplitude is given by a single diagram, with the topology of a torus. Its interpretation had remained obscure, because it was formally real, converged only for purely imaginary values of the Mandelstam variables, and had to account for the singularities of both the box graph and the one particle reduc

R. Jackiw

25th anniversary and new building dedication Centre de Recherches Mathématiques Montréal, Canada, October 1994

S. James Gates, L. Rana

By utilizing a new procedure (the RADIO method) for deriving on-shell 2D, 2N-extended multiplets from off-shell 2D, N-extended multiplets, we derive a new on-shell 2D, N = 8 representation; the ultra-multiplet. By twisting with respect to parity, we show that many variant versions of this supermultiplet also exist.

S. James Gates

We demonstrate the existence of three off-shell distinct N = 4 superstrings at the level of manifest locally supersymmetric Lagrangian field theories on the world sheet.

Mans Henningson

(Talk given at the Oskar Klein centenary symposium 19-21 September 1994 in Stockholm, Sweden, to appear in the proceedings.) The first half of this talk is a non-technical discussion of some general aspects of string theory, in particular the problem of compactification. We also give an introduction to mirror symmetry. The second half is a brief account of t

Ch. Devchand, V. Ogievetsky

There exist many four dimensional integrable theories. They include self-dual gauge and gravity theories, all their extended supersymmetric generalisations, as well the full (non-self-dual) N=3 super Yang-Mills equations. We review the harmonic space formulation of the twistor transform for these theories which yields a method of producing explicit connectio

Vadim B. Kuznetsov

We construct a class of representations of the quadratic R-matrix algebra, given by the reflection equation with the spectral parameter, in terms of certain ordinary difference operators. These operators turn out to act as parameter shifting operators on the 3_F_2(1) hypergeometric function and its limit cases and on classical orthogonal polynomials. The rel

J. Van der Jeugt, R. Jagannathan

We consider the algebra $R$ generated by three elements $A,B,H$ subject to three relations $[H,A]=A$, $[H,B]=-B$ and $\{A,B\}=f(H)$. When $f(H)=H$ this coincides with the Lie superalgebra $osp(1/2)$; when $f$ is a polynomial we speak of polynomial deformations of $osp(1/2)$. Irreducible representations of $R$ are described, and in the case $°(f)\leq 2$ we ob

Kun Chen, Gary R. Goldstein, R. L. Jaffe, Xiangdong Ji

We study the measurement of the quark fragmentation functions for spin-1/2 baryon production ($Λ$ and $\bar Λ$, in particular) in unpolarized $e^+e^-$ annihilation. The spin-dependent fragmentation functions $\hat g_1(z)$ and $\hat h_1(z)$ can be probed in the process as a result of quark-antiquark spin correlation and the weak decay of the baryons. The rele

W. Grimus, H. Neufeld

We study Cherenkov and transition radiation of neutral spin 1/2 particles which carry magnetic moments or electric dipole moments. In particular, we estimate the radiation caused by the solar neutrino flux in dielectric media.

A. W. Thomas

We review recent progress in the understanding of the spin structure of the nucleon. For the free nucleon the issues addressed include the status of the Bjorken and Ellis-Jaffe sum-rules and the role of the axial anomaly. We outline recent work connecting the quark models familiar from hadron spectroscopy to the spin and flavour dependence of the parton dist

Marek Jezabek

Compact analytic expressions have been obtained for the first order perturbative QCD corrections to the inclusive spectra of the leptons in the semileptonic decays of polarised heavy quarks. Charmed and beautiful $Λ$ baryons from $Z^0$ decays can be viewed as sources of highly polarised charm and bottom quarks. Charged leptons and neutrinos from $Λ_b$ and $Λ

Thomas Mannel, Gerhard A. Schuler

We formulate a QCD-based effective theory approach to heavy quarkonia-like systems as $\bar{c} c$ and $\bar{b} b$ resonances and $B_c$ states. We apply the method to inclusive decays, working out a few examples in detail.

Andrzej Czarnecki

A recently proposed method of calculating scalar two-loop propagator and vertex functions with massive particles is illustrated with simple examples. A double integral representation is derived with the example of a propagator function. An analogous representation is used to compute the vertex function for space-like external momenta. Ways of dealing with di

Bernd A. Kniehl

We review recent theoretical progress in the computation of radiative corrections beyond one loop within the standard model of electroweak interactions, both in the gauge and Higgs sectors. In the gauge sector, we discuss universal corrections of $Ø(G_F^2M_H^2M_W^2)$, $Ø(G_F^2m_t^4)$, $Ø(α_sG_FM_W^2)$, $Ø(α_s^2G_Fm_t^2)$, and those due to virtual $t\bar t$ t

J. M. Eisenberg

A system is studied in which initially a strong classical electric field exists within an infinitely-long cylinder and no charges are present. Subsequently, within the cylinder, pairs of charged particles tunnel out from the vacuum and the current produced through their acceleration by the field acts back on the field, setting up plasma oscillations. This yi

A. Brandenburg, V. V. Khoze, D. Müller

We calculate azimuthal asymmetries and the Callan-Gross $R$-ratio for semi-exclusive pion production in deep inelastic scattering taking into account higher twist effects. Our results are qualitatively different from the QCD-improved parton model predictions for semi-inclusive deep inelastic scattering.

UKQCD Collaboration

We use a method recently suggested for evaluating the slope of the Isgur-Wise function, at the zero-recoil point, on the lattice. The computations are performed in the quenched approximation to lattice QCD, on a $24^3 \times 48$ lattice at $β=6.2$, using an $O(a)$-improved action for the fermions. We have found unexpectedly large finite-volume effects in suc

UKQCD Collaboration

We present results of a lattice computation of the matrix elements of the vector and axial-vector currents which are relevant for the semi-leptonic decays $D \rightarrow K$ and $D \rightarrow K^*$. The computations are performed in the quenched approximation to lattice QCD on a $24^3 \times 48$ lattice at $β=6.2$, using an $O(a)$-improved fermionic action. I

G. Horwitz, O. Fonarev

Multibubble solutions for a cosmological model which lead to thermal inflationary states due to a semi-classical tunneling of gravity are calculated.

Nigel B. Wilding, Marcus Mueller

Monte Carlo simulations within the grand canonical ensemble are used to obtain the joint distribution of density and energy fluctuations $p_L(ρ,u)$ for two model fluids: a decorated lattice gas and a polymer system. In the near critical region the form of $p_L(ρ,u)$ is analysed using a mixed field finite-size-scaling theory that takes account of liquid-vapou

P. W. Brouwer, C. W. J. Beenakker

The effect of an invasive voltage probe on the phase-coherent conduction through a ballistic chaotic cavity is investigated by random-matrix theory. The entire distribution P(G) of the conductance G is computed for the case that the cavity is coupled to source and drain by two point contacts with a quantized conductance of 2 e^2/h, both in the presence (beta

Christy Doran, Dania Egedi, Beth Ann Hockey, B. Srinivas

This paper presents the XTAG system, a grammar development tool based on the Tree Adjoining Grammar (TAG) formalism that includes a wide-coverage syntactic grammar for English. The various components of the system are discussed and preliminary evaluation results from the parsing of various corpora are given. Results from the comparison of XTAG against the IB

Dirk Heylen, Kerry G. Maxwell, Marc Verhagen

This paper discusses the lexicographical concept of lexical functions and their potential exploitation in the development of a machine translation lexicon designed to handle collocations.

Jussi Karlgren, Douglass Cutting

A simple method for categorizing texts into predetermined text genre categories using the statistical standard technique of discriminant analysis is demonstrated with application to the Brown corpus. Discriminant analysis makes it possible use a large number of parameters that may be specific for a certain corpus or information stream, and combine them into

B. Fernandez

We examine the problem of the dynamics of interfaces in a one-dimensional space-time discrete dynamical system. Two different regimes are studied : the non-propagating and the propagating one. In the first case, after proving the existence of such solutions, we show how they can be described using Taylor expansions. The second situation deals with the assump

Vladimir V. Lebedev, Victor S. L'vov

It is shown that statistical properties of developed hydrodynamic turbulence are characterized by an infinite set of independent anomalous exponents which describes the scaling behavior of hydrodynamic fields constructed from the second and larger powers of the velocity derivatives. A physical mechanism responsible for anomalous scaling, ``telescopic multi-s

V. S L'vov, I. Procaccia

A synopsis of an analytical theory of scaling in developed turbulence is proposed on the basis of the Navier-Stokes equations. It is shown that corrections to the normal Kolmogorov 1941 scaling behavior of the $n$-th order velocity structure functions are finite Re effects which disappear when the inertial interval exceeds 5-6 decades. These corrections orig

Henry E. Kandrup, M. Elaine Mahon

This paper proposes an alternative characterisation of the degree of stochasticity exhibited by orbits in a fixed galactic potential. This differs from earlier work involving Liapounov exponents by focusing on the statistical properties of ensembles of trajectories, rather than individual orbits, and by restricting attention to the properties of these ensemb

Edward L. Wright

The Quasi-Steady-State Cosmology as proposed by Hoyle, Burbidge and Narlikar does not fit the observed facts of the Universe. In particular, it predicts that 75-90\% of the radio sources in the brightest sample that shows steeper than Euclidean source counts should be blueshifted.

Jerome W. Elbert, Paul Sommers

The 320 EeV air shower detected by the Fly's Eye poses an important problem. Careful analysis of pathlength limitations for the possible particle types due to cosmic background radiation verifies that the particle very likely traveled less than 50 Mpc from its source. The best candidates for accelerating particles to such high energies are the very power

Michael S. Vogeley

The power spectrum of density fluctuations measured from galaxy redshift surveys provides important constraints on models for the formation of large-scale structure. I present new results for a redshift sample of 15,000 galaxies, and review the limitations of current measurements. To span the decade of wavelength between the scales probed by galaxy surveys a

D. J. Bird et al.

We report the detection of a 51-joule (320 +/- 90 EeV) cosmic ray by the Fly's Eye air shower detector in Utah. This is substantially greater than the energy of any previously reported cosmic ray. A Greisen-Zatsepin-Kuz'min cutoff of the energy spectrum (due to pion photoproduction energy losses) should occur below this energy unless the highest ener

L. N. da Costa, M. S. Vogeley, M. J. Geller, J. P. Huchra

We compute the power spectrum of galaxy density fluctuations in a recently completed redshift survey of optically-selected galaxies in the southern hemisphere (SSRS2). The amplitude and shape of the SSRS2 power spectrum are consistent with results of the Center for Astrophysics redshift survey of the northern hemisphere (CfA2), including the abrupt change of

Geza Gyuk, Michael S. Turner

Terrestrial and ``Heavenly'' experiments severely constrain the mass and lifetime of an MeV tau neutrino. Irrespective of decay mode, for $τ_ν\ga 300\sec$ the mass of the tau neutrino must be either approximately $30\MeV$ or less than $0.4\MeV$ (Majorana), $15\keV$ (Dirac). If the dominant decay mode includes electromagnetic daughter products, the ma

Devendra Ojha

We try here to find new constraints on thick disk population using samples at intermediate latitude and North Galactic Pole, which include photometry and proper motions. The algorithm SEM (Stochastic-Estimation-Maximization; Celeux \& Deibolt 1986) was used to deconvolve the stellar components up to large distances above the plane, allowing to study of their

H. Falcke, O. M. Heinrich

The low accretion rate inferred for the GC source Sgr A* requires a distinct type of accretion disk -- a starving disk. We investigate the structure of this type of disk within the framework of thin Keplerian disk models taking into account relativistic effects, detailed opacitiy tables and turbulent heat transport. It appears as if starving disks are the pe

Bas Edixhoven

This article improves certain results of Dino Lorenzini concerning the groups of connected components of special fibres of Néron models of abelian varieties. Lorenzini has shown the existence of a four step filtration on the prime-to-$p$ part ($p$ is the residue characteristic), and proved certain bounds for the successive quotients. We improve these bounds

M. E. J. Newman, B. W. Roberts

We present a new model for extinction in which species evolve in bursts or `avalanches', during which they become on average more susceptible to environmental stresses such as harsh climates and so are more easily rendered extinct. Results of simulations and analytic calculations using our model show a power-law distribution of extinction sizes which is

C. P. Burgess, R. C. Myers, F. Quevedo

We reconsider here the problem of finding the general 4D spherically symmetric, asymptotically flat and time-independent solutions to the lowest-order string equations in the $\ap$ expansion. Our construction includes earlier work, but differs from it in three ways. (1) We work with general background metric, dilaton, axion and $U(1)$ gauge fields. (2) Much

J. P. Rodriguez, J. Bonca, J. Ferrer

The square lattice spin-1/2 antiferromagnet containing a dilute concentration, $δ$, of randomly placed ferromagnetic nearest-neighbor bonds is studied at low-temperature via non-linear $σ$-model techniques and by exact diagonalization. We generally find that long-range N\' eel order is destroyed above a critical strength in the defective ferromagnetic ex

D. J. Millener, C. B. Dover, A. Gal

The $Λ$ and neutron decay widths of $Ξ$ hypernuclear states, based on calculated $ΞN \to \lala$ mixing amplitudes, are estimated. The widths which result from using the Nijmegen Model D interaction are sufficiently small, of order 1.5 MeV, that experiments to observe $Ξ$ hypernuclear states using the $(K^-,K^+)$ reaction may be feasible.

Philip R. Page

We have examined decays of low-lying gluonic excitations of mesons (hybrids) by chromoelectric flux-tube breaking. An analytical calculation of non-relativistic flux-tube model decay amplitudes is performed in an harmonic oscillator approximation. Specific decay signatures of all $J^{PC}$ charmonium hybrids are identified and the widths predicted. We introdu

J. Schechter, H. Weigel

We formulate the particle conjugation operation and its convenient realization as $G$--parity in the framework of several chiral soliton models. The Skyrme model, the Skyrme model with vector mesons and the chiral quark model are specifically treated. The vector and axial vector currents are classified according to their behavior under $G$--parity. In the so

J. L Vazquez-Bello

{ This letter discusses the BRST cohomology of superparticles type I and II. It was used an extended super-space to construct $S0(9,1)$ superparticle actions that lead to super-wave functions whose spinor components satisfy $S0(9,1)$ covariant constraints. Their BRST charges were found by using BV methods, since the models present a large number of symmetrie

Tim R. Morris

Direct verification of the existence of an infinite set of multicritical non-perturbative FPs (Fixed Points) for a single scalar field in two dimensions, is in practice well outside the capabilities of the present standard approximate non-perturbative methods. We apply a derivative expansion of the exact RG (Renormalization Group) equations in a form which a

N. N. Nikolaev, B. G. Zakharov, V. R. Zoller

We demonstrate that the diffraction slope of the generalized BFKL pomeron amplitude has the conventional Regge growth $B(s) = B(0) + 2α_{\Pom}'\log(s)$. This proves that the generalized BFKL pomeron is described by the moving $j$-plane singularity. We give an estimate for the slope $α_{\Pom}'$ in terms of the correlation radius for the perturbative g

V. Braun, P. Górnicki, L. Mankiewicz

We argue that parton distributions in coordinate space provide a more natural object for nonperturbative methods compared to the usual momentum distributions in which the physics of different longitudinal distances is being mixed. To illustrate the advantages of the coordinate space formulation, we calculate the coordinate space distributions for valence qua

B. B. Levchenko

New properties of the multiplicity distributions predicted by higher order QCD and their physical origin are discussed briefly. Several studies which can be performed at HERA are proposed.

K. Saito, A. W. Thomas

Using a self-consistent quark model for nuclear matter we investigate variations of the masses of the non-strange vector mesons, the hyperons and the nucleon in dense nuclear matter (up to four times the normal nuclear density). We find that the changes in the hadron masses can be described in terms of the value of the scalar mean-field in matter. The model

C. R. Chinn, A. S. Umar, M. Vallières, M. R. Strayer

{Full three dimensional static and dynamic mean field calculations using collocation basis splines with a Skyrme type Hamiltonian are described. This program is developed to address the difficult theoretical challenges offered by exotic nuclei. Ground state and deformation properties are calculated using static Hartree-Fock, Hartree-Fock+BCS and constrained

C. R. Chinn, J. Dechargé, J. -F. Berger

A many-body calculation of $^{11}$Li is presented where the only input is the well-tested, finite-range {\it D1S} effective interaction of {\it Gogny}. Pairing correlations are included in a constrained Hartree-Fock-Bogolyubov calculation, while long-range collective correlations are introduced using a GCM derived calculation. Correlations are found to play

A. Gil, E. Oset

We have studied the pion^{-} capture in nuclei leading to two photons, using improved many body methods which have been tested with success in one photon pion^{-} radiative capture, muon^{-} capture and neutrino scattering. The qualitative features of the experimental data are reproduced but there are still some disagreement at small relative photon angles.

C. R. Chinn, Ch. Elster, R. M. Thaler, S. P. Weppner

Measurements of neutron total cross-sections are both extensive and extremely accurate. Although they place a strong constraint on theoretically constructed models, there are relatively few comparisons of predictions with experiment. The total cross-sections for neutron scattering from $^{16}$O and $^{40}$Ca are calculated as a function of energy from $50-70

H. Gustafsson, U. Lindström, P. Saltsidis, B. Sundborg

We present a new formulation of the tensionless string ($T= 0$) where the space-time conformal symmetry is manifest. Using a Hamiltonian BRST scheme we quantize this {\em Conformal String} and find that it has critical dimension $D=2$. This is in keeping with our classical result that the model describes massless particles in this dimension. It is also consi

Nicholas Dorey, Timothy J. Hollwood

The scattering of charged solitons in the complex sine-Gordon field theory is investigated. An exact factorizable S-matrix for the theory is proposed when the renormalized coupling constant takes the values $λ^{2}_{R}=4π/k$ for any integer $k>1$: the minimal S-matrix associated with the Lie algebra $a_{k-1}$. It is shown that the proposed S-matrix reproduces

M. Bonini, M. D'Attanasio, G. Marchesini

In the exact renormalization group (RG) flow in the infrared cutoff $Λ$ one needs boundary conditions. In a previous paper on $SU(2)$ Yang-Mills theory we proposed to use the nine physical relevant couplings of the effective action as boundary conditions at the physical point $Λ=0$ (these couplings are defined at some non-vanishing subtraction point $μ\ne 0$

Mark Rakowski

Lattice gauge theory with gauge group $Z_{P}$ is reconsidered in four dimensions on a simplicial complex $K$. One finds that the dual theory, formulated on the dual block complex $\hat{K}$, contains topological modes which are in correspondence with the cohomology group $H^{2}(\hat{K},Z_{P})$, in addition to the usual dynamical link variables. This is a gene

E. J. Copeland, Amitabha Lahiri, David Wands

We present a class of exact solutions for homogeneous, anisotropic cosmologies in four dimensions derived from the low-energy string effective action including a homogeneous dilaton $ϕ$ and antisymmetric tensor potential $B_{μν}$. Making this potential time-dependent produces an anisotropic energy-momentum tensor, and leads us to consider a Bianchi I cosmolo

A. Aghamohammadi, M. Khorrami, A. Shariati

We show that $h$-deformation can be obtained, by a singular limit of a similarity transformation, from $q$-deformation; to be specefic, we obtain $\GL_h(2)$, its differential structure, its inhomogenous extension, and $\Uh{\sl(2)}$ from their $q$-deformed counterparts.

Sherman Frankel

The claims for production of high energy densities and possible new states of matter in collisions of nuclei by George F. Bertsch (Science, {\bf 265} (1994) 480-481) are examined and compared with simple explanations of the data which have appeared in the literature.

K. S. Babu, R. N. Mohapatra

We give a general prescription for deriving quark and lepton mass matrices with ``texture'' zeros in the framework of superstring inspired $SO(10)$ models. The key to our approach is a new way to naturally implement the doublet--triplet splitting which enables us to obtain symmetric quark and lepton mass matrices which have different structures in th

Robert Bluhm, Alan Kostelecky

We show that a theoretical description of radial Rydberg wave packets in alkali-metal atoms based solely on hydrogenic wave functions and energies is insufficient to explain data that could be obtained in pump-probe experiments with current technology. The modifications to long-term revival times induced by quantum defects cannot be obtained by direct scalin

M. Sutherland, B. Holdom, S. Jaimungal, Randy Lewis

A relativistic quark model is extended to incorporate chiral and gauge symmetries. We obtain the DD*pi and DD*gamma couplings and find that the ratio Gamma(D*0->D0pi0)/Gamma(D*0->D0gamma) constrains the charm-quark mass close to 1.45 GeV. Large 1/mc corrections appear in the heavy-quark contribution to the DD*gamma coupling. The model is extended further to

F. Caravaglios, G. G. Ross

We consider whether a discrepancy between the SLAC and LEP measurements of $\Sw$ can be explained by new physics. We find that only the contribution of a new neutral gauge boson, $Z^\prime$, nearly degenerate with the Z can affect the SLAC measurement while leaving the LEP observables almost unaffected. We briefly discuss possible signals for this new gauge