August 1995 arXiv papers — page 10

M. Göckeler, R. Horsley, E. -M. Ilgenfritz, H. Perlt

We report on a high statistics quenched lattice QCD calculation of the deep-inelastic structure functions $F_1$, $F_2$, $g_1$ and $g_2$ of the proton and neutron. The theoretical basis for the calculation is the operator product expansion. We consider the moments of the leading twist operators up to spin four. Using Wilson fermions the calculation is done fo

David A. Craig

This paper examines an observable consequence for the diffuse extragalactic background radiation (EGBR) of the hypothesis that if closed, our universe possesses time symmetric boundary conditions. For simplicity, attention is focused on optical wavelengths. The universe is modeled as closed Friedmann- Roberston-Walker. It is shown that, over a wide range of

I. Aranson, B. Ya. Shapiro, V. Vinokur

We investigate the kinetics of normal phase nucleation and flux line condensation in the type-II superconductors by numerical study of the time-dependent Ginzburg-Landau equation. We have shown that under the sufficient transport current the normal phase nucleates in the superconducting strips in a form of the macroscopic droplets having the multiple topolog

Joseph I. Kapusta, Axel P. Vischer

We estimate the probability that a hard nucleon-nucleon collision is able to nucleate a seed of quark--gluon plasma in the surrounding hot and dense hadronic matter formed during a central collision of two large nuclei at AGS energies. The probability of producing at least one such seed is on the order of 1-100\%. We investigate the influence of quark--gluon

Sanjay Reddy, Madappa Prakash

Neutrino processes in dense matter play a key role in the dynamics, deleptonization and early cooling of hot protoneutron stars formed in the gravitational collapse of massive stars. Here we calculate neutrino mean free paths from neutrino-hyperon interactions in dense matter containing hyperons. Significant contributions to the neutrino opacity arise from s

T. Kubo, E. Lehmann, Amand Faessler, Rajeev K. Puri

We study the effect of the density dependence of the scalar and the vector part of the nucleonic self-energy in Relativistic Quantum Molecular Dynamics (RQMD) on observables like the transversal flow and the rapidity distribution. The stability of nuclei in RQMD is greatly improved if the density dependence is included in the self-energies compared to a calc

G. F. Filippov, I. Yu. Rybkin, S. V. Korennov

By using the method of hyperspherical functions within the appropriate for this method $K_{\min}$ approximation, the simple three-cluster model for description of the ground state and the continuous spectrum states of \6He is developed. It is shown that many properties of \6He (its large rms radius and large values of the matrix elements of electromagnetic t

Iris Inbar, R. E. Cohen

This paper explains the origin of the ferroelectric instability in LiNbO3 and LiTaO3 and compares the electronic structures and energetics of the two materials.

Vipul Periwal

The flow of couplings under anisotropic scaling of momenta is computed in $ϕ^3$ theory in 6 dimensions. It is shown that the coupling decreases as momenta of two of the particles become large, keeping the third momentum fixed, but at a slower rate than the decrease of the coupling if all three momenta become large simultaneously. This effect serves as a simp

Stefano De Leo

We reformulate Special Relativity by a quaternionic algebra on reals. Using {\em real linear quaternions}, we show that previous difficulties, concerning the appropriate transformations on the $3+1$ space-time, may be overcome. This implies that a complexified quaternionic version of Special Relativity is a choice and not a necessity.

Stefano De Leo

We develop a relativistic free wave equation on the complexified quaternions, linear in the derivatives. Even if the wave functions are only one-component, we show that four independent solutions, corresponding to those of the Dirac equation, exist. A partial set of translations between complex and complexified quaternionic quantum mechanics may be defined.

M. Anazawa, A. Ishikawa, H. Itoyama

From the computation of three-point singlet correlators in the two-matrix model, we obtain an explicit expression for the macroscopic three-loop amplitudes having boundary lengths $\ell_{i}$ $(i = 1\sim 3)$ in the case of the unitary series $(p,q)= (m+1,m)$ coupled to two-dimensional gravity. The sum appearing in this expression is found to conform to the st

G. Lazarides, N. D. Vlachos

We estimate the contribution of a class of multiinstanton ladder graphs to baryon and lepton number violating processes in the standard model. We find that this contribution is negligible and does not alter the high energy behavior of the leading semiclassical approximation.

D. Coulson, Z. Lalak, B. Ovrut

Non-equilibrium phase transitions of a scalar field in an expanding spacetime are discussed. These transitions are shown to lead, for appropriate potential energy functions, to a biased choice of vacuum structure which can be analytically described using percolation theory. The initial domain wall networks, which form between different vacua, are evolved in

M. R. Frank, C. D. Roberts

A one parameter, model confined-gluon propagator is employed in a phenomenological application of the Dyson-Schwinger and Bethe-Salpeter equations to the calculation of a range of $π$- and $ρ$-meson observables. Good agreement is obtained with the data. The calculated quark propagator does not have a singularity on the real-$p^2$ axis. A mass formula for the

A. Edin, G. Ingelman, J. Rathsman

We present a new mechanism for the creation of large rapidity gaps in DIS events at HERA. Soft colour interactions between perturbatively produced partons and colour-charges in the proton remnant, modifies the colour structure for hadronization giving colour singlet systems that are well separated in rapidity. An explicit model is presented that, although th

Arild Skjold, Per Osland

In a more general electroweak theory, there could be Higgs particles that are odd under $CP$. Correlations among momenta of the initial electron and final-state fermions are in the Bjorken process sensitive to the $CP$ parity. Monte Carlo data on the expected efficiency demonstrate that it should be possible to verify the scalar character of an intermediate-

C. Hamzaoui, M. E. Pospelov

The pure electroweak three-loop mechanism for the induced electric and chromoelectric dipole moments of quarks is studied in the Kobayashi-Maskawa model with three and four generations. In the standard three generation case, this mechanism is found to produce a negligible contribution to the electric dipole moment of neutron. In the presence of the fourth he

CLEO Collaboration, T. Bergfeld et al

We have observed two new decay modes of the charmed baryon $Ξ_c^+$ into $Σ^+ K^-π^+$ and $Σ^+ \bar{K}^{*0}$ using data collected with the CLEO II detector. We also present the first measurement of the branching fraction for the previously observed decay mode $Ξ_c^+\toΛK^-π^+π^+$. The branching fractions for these three modes relative to $Ξ_c^+\toΞ^-π^+π^+$ a

CLEO Collaboration, J. Alexander et al

We report the observation of the Cabibbo-suppressed decays \lcpkk\ and \lcpphi\ using data collected with the CLEO II detector at CESR. The latter mode, observed for the first time with significant statistics, is of interest as a test of color-suppression in charm decays. We have determined the branching ratios for these modes relative to \lcpkpi\ and compar

CLEO Collaboration, D. M. Asner et al

We have searched for two-body charmless hadronic decays of $B$ mesons. Final states include $ππ$, $K π$, and $KK$ with both charged and neutral kaons and pions; $πρ$, $K ρ$, and $K^*π$; and $Kϕ$, $ K^*ϕ$, and $ϕϕ$. The data used in this analysis consist of 2.6~million $B\bar{B}$~pairs produced at the $Υ(4S)$ taken with the CLEO-II detector at the Cornell Ele

J. A. Nieto

Using a classical action associated to a point-particle in (1+1)-dimensions the classical string theory is derived. In connection with this result two aspects are clarified: First, the point particle in (1+1)-dimensions is not an ordinary relativistic system, but rather a some kind of a relativistic top; and second, through the quantization of such a kind of

C. G. Torre

Many important features of a field theory, {\it e.g.}, conserved currents, symplectic structures, energy-momentum tensors, {\it etc.}, arise as tensors locally constructed from the fields and their derivatives. Such tensors are naturally defined as geometric objects on the jet space of solutions to the field equations. Modern results from the calculus on jet

Man Chun Leung

Comparisons on $L^{n\over 2}$-norms of scalar curvatures between Riemannian metrics and standard metrics are obtained. The metrics are restricted to conformal classes or under certain curvature conditions.

G. Gomez-Santos

Numerical analysis of the spectrum of large finite size Luttinger liquids (g<1) in the presence of a single source of 2k_f scattering has been made possible thanks to an effective integration of high degrees of freedom. Presence of irrelevant operators and their manifestation in transport are issues treated independently. We confirm the existence of two irre

Takashi Yamamoto

A new one-dimensional model, the multicomponent Calogero model of $B_N$-type confined in the harmonic potential, is introduced. The Lax pair of this model is determined, and then a set of functionally independent conserved operators are constructed. Moreover, the energy spectrums of the above model are obtained by three different methods.

Aris L. Moustakas, Daniel S. Fisher

It has been claimed that an impurity hopping between two sites in a metal can lead to non--Fermi liquid behavior if the bias between the two sites is tuned to zero. Here it is shown that several extra tunnelling processes are allowed; those involving bare impurity tunnelling as well as two--electron--assisted tunnelling play important roles. These terms gene

B. A. Shadwick, John C. Bowman, P. J. Morrison

Traditional numerical discretizations of conservative systems generically yield an artificial secular drift of any nonlinear invariants. In this work we present an explicit nontraditional algorithm that exactly conserves these invariants. We illustrate the general method by applying it to the three-wave truncation of the Euler equations, the Lotka--Volterra

John C. Bowman

Inertial-range scaling laws for two- and three-dimensional turbulence are re-examined within a unified framework. A new correction to Kolmogorov&#39;s $k^{-5/3}$ scaling is derived for the energy inertial range. A related modification is found to Kraichnan&#39;s logarithmically corrected two-dimensional enstrophy-range law that removes its unexpected diverge

Ramesh Narayan, Jeffrey E. McClintock, Insu Yi

We present models of the soft X-ray transients, A0620-00, V404 Cyg, and X-ray Nova Mus 1991, in quiescence. In each source, we postulate that there is an outer region, extending outward from about 3000 Schwarzschild radii, where the accretion flow is in the form of a standard thin disk. The outer disk produces most of the radiation we observe in the infrared

C. Hagmann, W. Stoeffl, K. van Bibber, E. Daw

An experiment is described to detect dark matter axions trapped in the halo of our galaxy. Galactic axions are converted into microwave photons via the Primakoff effect in a static background field provided by a superconducting magnet. The photons are collected in a high Q microwave cavity and detected by a low noise receiver. The axion mass range accessible

O. Lahav, A. Naim, L. Sodre, M. C. Storrie-Lombardi

We apply and compare various Artificial Neural Network (ANN) and other algorithms for automatic morphological classification of galaxies. The ANNs are presented here mathematically, as non-linear extensions of conventional statistical methods in Astronomy. The methods are illustrated using different subsets Artificial Neural Network (ANN) and other algorithm

William B. Latter, Douglas M. Kelly, Joseph L. Hora, Lynne K. Deutsch

We present the results of a near-infrared narrowband imaging survey of planetary nebulae. Objects were selected in a way that complements similar surveys done at visible and near-infrared wavelengths. No new detections of molecular hydrogen emission were made. The H2 is frequently found to be extended, except in young, visibly compact objects. Our results ar

Martin White, Douglas Scott, Joe Silk, Marc Davis

The Cold Dark Matter (CDM) model has an elegant simplicitly which makes it very predictive, but when its parameters are fixed at their `canonical&#39; values its predictions are in conflict with observational data. There is, however, much leeway in the initial conditions within the CDM framework. We advocate a re-examination of the CDM model, taking into acc

F. L. Bezrukov, M. V. Libanov, S. V. Troitsky

We solve the classical euclidean boundary value problem for tree-level multiparticle production in $ϕ^4$ theory at arbitrary energies in the case of $O(4)$ symmetric field configurations. We reproduce known low-energy results and obtain a lower bound on the tree cross sections at arbitrary energies.

H. C. Rosu, M. A. Reyes, O. Obregón

Using a simple factorization scheme we obtain the recurrence-shift relations of the polynomial functions of Aldaya, Bisquert and Navarro-Salas (ABNS), F_n^N(\fracωc\sqrtN x), i.e., one-step first-order differential relations referring to N, as follows. Firstly, we apply the scheme to the polynomial degree confirming the recurrence relations of Aldaya, Bisque

Matteo Beccaria

The $(g_2^{(1)}, d_4^{(3)})$\ pair of non simply laced affine Toda theories is studied from the point of view of non perturbative duality. The classical spectrum of each member is composed of two massive scalar particles. The exact S-matrix prediction for the dual behaviour of the coupling dependent mass ratio is found to be in strong agreement with Monte Ca

Anne-Marie Mineur, Paul Buitelaar

We discuss an extension of the standard logical rules (functional application and abstraction) in Categorial Grammar (CG), in order to deal with some specific cases of polysemy. We borrow from Generative Lexicon theory which proposes the mechanism of {\em coercion}, next to a rich nominal lexical semantic structure called {\em qualia structure}. In a previou

G. Bélanger

The physics potential of a high-energy photon collider is reviewed. The emphasis is put on aspects related to the symmetry breaking sector, including Higgs searches and production of longitudinal vector bosons.

C. F. Baillie, D. A. Johnston

We discuss the utility of analytical and numerical investigation of spin models, in particular spin glasses, on ordinary ``thin&#39;&#39; random graphs (in effect Feynman diagrams) using methods borrowed from the ``fat&#39;&#39; graphs of two dimensional gravity. We highlight the similarity with Bethe lattice calculations and the advantages of the thin graph

A. M. Green, J. Lukkarinen, P. Pennanen, C. Michael

The energies of four-quark states are calculated for geometries in which the quarks are situated on the corners of a series of tetrahedra and also for geometries that correspond to gradually distorting these tetrahedra into a plane. The interest in tetrahedra arises because they are composed of {\bf three } degenerate partitions of the four quarks into two t

Edwin Langmann

Consistent Yang--Mills anomalies $\int\om_{2n-k}^{k-1}$ ($n\in\N$, $ k=1,2, \ldots ,2n$) as described collectively by Zumino&#39;s descent equations $δ\om_{2n-k}^{k-1}+\dd\om_{2n-k-1}^{k}=0$ starting with the Chern character $Ch_{2n}=\dd\om_{2n-1}^{0}$ of a principal $\SU(N)$ bundle over a $2n$ dimensional manifold are considered (i.e.\ $\int\om_{2n-k}^{k-1}

Koji Niita, Satoshi Chiba, Toshiki Maruyama, Tomoyuki Maruyama

We propose a model based on quantum molecular dynamics (QMD) incorporated with statistical decay model (SDM) to describe various nuclear reactions in an unified way. In this first part of the work, the basic ingredients of the model are defined and the model is applied systematically to the nucleon($N$)-induced reactions. It has been found that our model can

A. Zujewski

We consider the semidirect product of diffeomorphisms of the circle $D={Diff}_+(S^1)$ and $C^{\infty}(S^{1}, {\bf R})$ functions, classify its coadjoint orbits and prove the integrability of hamiltonian (Generalized Dispersive Water Waves (DWW) and KdV-type) systems related to corresponding Lie algebra centrally extended by Kac-Moody, Virasoro and semidirect

Domenico Giulini

We reinvestigate Bargmann&#39;s superselection rule for the overall mass of $n$ particles in ordinary quantum mechanics with Galilei invariant interaction potential. We point out that in order for mass to define a superselection rule it should be considered as a dynamical variable. We present a minimal extension of the original dynamics in which mass it trea

J. Grunhaus, S. Popescu, D. Rohrlich

We present a possible scheme to tamper with non-local quantum correlations in a way that is consistent with relativistic causality, but goes beyond quantum mechanics. A non-local ``jamming&#34; mechanism, operating within a certain space-time window, would not violate relativistic causality and would not lead to contradictory causal loops. The results presen

A. N. Antonov, M. V. Stoitsov, M. K. Gaidarov, S. S. Dimitrova

A method to calculate the hole spectral function in the discrete part of the spectrum is suggested within the natural orbital representation of the one-body density matrix of $A$-nucleon system using its relationship with the overlap functions of the eigenstates in the $(A-1)$-nucleon system.

C. Hanhart, J. Haidenbauer, A. Reuber, C. Schütz

We perform a momentum-space calculation of the reaction $pp \rightarrow ppπ^0$ near threshold. Direct production and pion rescattering are taken into account. For the latter a T-matrix obtained from a microscopic model of the $πN$ interaction is employed. The effects of some approximations commonly used in studies of $ pp \rightarrow ppπ^0$ \ are discussed.

Walter R. L. Lambrecht, Benjamin Segall

The band structures of 6H and 4H SiC calculated by means of the FP-LMTO method are used to determine the effective mass tensors for their conduction-band minima. The results are shown to be consistent with recent optically detected cyclotron resonance measurements and predict an unusual band filling dependence for 6H-SiC.

A. G. Petukhov, W. R. L. Lambrecht, B. Segall

Resonant tunneling through semimetallic ErAs quantum wells embedded in GaAs structures with AlAs barriers was recently found to exhibit an intriguing behavior in magnetic fields which is explained in terms of tunneling selection rules and the spin-polarized band structure including spin-orbit coupling.

Christopher J. Bishop, Peter Jones, Robin Pemantle, Yuval Peres

Consider a planar Brownian motion run for finite time. The frontier or ``outer boundary&#39;&#39; of the path is the boundary of the unbounded component of the complement. Burdzy (1989) showed that the frontier has infinite length. We improve this by showing that the Hausdorff dimension of the frontier is strictly greater than 1. (It has been conjectured tha

Bjorn Poonen

Let $C$ be an algebraically closed field containing the finite field $F_q$ and complete with respect to an absolute value $|\;|$. We prove that under suitable constraints on the coefficients, the series $f(z) = \sum_{n \in \Z} a_n z^{q^n}$ converges to a surjective, open, continuous $F_q$-linear homomorphism $C \rightarrow C$ whose kernel is locally compact.

Bjorn Poonen, Michael Rubinstein

We give a formula for the number of interior intersection points made by the diagonals of a regular $n$-gon. The answer is a polynomial on each residue class modulo 2520. We also compute the number of regions formed by the diagonals, by using Euler&#39;s formula $V-E+F=2$.

Vladimir Kanovei

We prove that if every real belongs to a set generic extension of the constructible universe then every Σ_1^1 equivalence E on reals either admits a Delta_1^HC reduction to the equality on the set 2^{<\om_1} of all countable binary sequences, or continuously embeds E_0, the Vitali equivalence. The proofs are based on a topology generated by OD sets.

Roelof W. Bruggeman

We consider invariant hyperfunctions associated to automorphic forms on the upper half plane. We give two interpretations of the period function of Maass forms introduced by Lewis. The first interpretation shows that the period function arises from the explicit description of a representative of the hyperfunction associated to the Maass form. Under certain c

Karabegov Alexander

We give a simple geometric description of all formal deformation quantizations on a Kähler manifold $M$ which enjoy the following property of separation of variables into holomorphic and antiholomorphic ones. For each open subset $U\subset M$, $\star$-multiplication from the left by a holomorphic function and from the right by an antiholomorphic function on

Suemi Rodríguez-Romo

We present a real space renormalization-group map for probabilities of random walks on a hierarchical lattice. From this, we study the asymptotic behavior of the end-to-end distance of a weakly self- avoiding random walk (SARW) that penalizes the (self-)intersection of two random walks in dimension four on the hierarchical lattice.

A. Armoni, J. Sonnenschein

We discuss bosonized two-dimensional QCD with massless fermions in the adjoint and multi-flavor fundamental representations. We evaluate the massive mesonic spectra of several models by using the light-front quantization and diagonalizing the mass operator $M^2=2P^+P^- $. We recover previous results in the case of one flavor adjoint fermions and we find the

Marco Bertola, Vittorio Gorini, Mauro Zeni

We consider the thermal properties of a scalar field theory on curved spacetimes. In particular, we argue for the existence in the de Sitter, Kruskal and Rindler manifolds of a discrete spectrum of allowed temperatures (the odd multiples of a fundamental one). For each temperature we give an explicit construction of the relative two point function in terms o

Manuel Drees, Rohini M. Godbole

We review the present level of knowledge of the hadronic structure of the photon, as revealed in interactions involving quarks and gluons ``in&#34; the photon. The concept of photon structure functions is introduced in the description of deep--inelastic $e γ$ scattering, and existing parametrizations of the parton densities in the photon are reviewed. We the

Damien Pierce

We apply the full one-loop corrections to the masses, gauge couplings, and Yukawa couplings in the minimal supersymmetric standard model. We focus on predictions for the strong coupling and the bottom-quark pole mass in the context of SU(5) supersymmetric grand unification. We discuss our results in both the small and large $\tanβ$ regimes. We demonstrate th

E. Quack, D. K. Srivastava

Direct photon production data at fixed target and collider experiments from $pp$ and $\bar{p}p$ collisions are analysed in NLO QCD. The results are grouped into three sets having $\sqrt{s}=20-30$ GeV, 630 GeV and 1.8 TeV. It is seen that at the lowest energies considered, the theory systematically underpredicts the results for all the values of the transvers

Pietro Colangelo

I discuss QCD sum rules determinations of the form factors governing the decay $B \to π(ρ) \ell ν$. For some of these form factors the computed dependence on the momentum transferred does not agree with the expectation from the nearest pole dominance hypothesis. Relations are observed among the form factors, that seem to be compatible with equations recently

Pankaj Jain

We show that composite fermions with masses much smaller than the scale of confinement arise naturally in certain models which admit dynamical breakdown of chiral symmetry. The models are such that to leading order some of the fermions remain massless but pick up small dynamical masses at subleading order.

K. Tamvakis

We study Radiative Electroweak Symmetry Breaking in the Minimal Supersymmetric Standard Model (MSSM). We employ the 2-loop Renormalization Group equations for running masses and couplings taking into account sparticle threshold effects. The decoupling of each particle below its threshold is realized by a step function in all one-loop Renormalization Group eq

Mohammad R. Ahmady

We analyse the long-distance contribution to $B\to X_s\ell^+\ell^-$ differential decay rate when the momentum dependence of $ψ$ and $ψ&#39;$-$γ$ conversion strength is taken into account. The results indicate that the resonance to nonresonance interference in the dilepton invariant mass distribution is substantially reduced.

S. Willenbrock

I discuss some of the physics of the top quark which will be explored in the near and more-distant future at the Tevatron.

C. Glenn Boyd, Benjamin Grinstein, Richard F. Lebed

We present nonperturbative, model-independent parametrizations of the individual QCD form factors relevant to B -> D* l nu and B -> D l nu decays. These results follow from dispersion relations and analyticity, without recourse to heavy quark symmetry. To describe a form factor with two percent accuracy, three parameters are necessary, one of which is its no

O. A. Borisenko, V. K. Petrov, G. M. Zinovjev, J. Boháčik

In the context of reviewing noncompact lattice gauge models at zero and finite temperature we study in detail a contribution of the invariant measure and the time-like plaquette configurations to correlation functions, analyze the problem of the compactness of the potentials in respect to the confinement and indicate the essential features to deal with the W

H. Jeon, M. Longo

There have been many searches for magnetic monopoles in flight, but few for monopoles in matter. We have searched for magnetic monopoles in meteorites, schists, ferromanganese nodules, iron ores and other materials. The detector was a superconducting induction coil connected to a SQUID (Superconducting Quantum Interference Device) with a room temperature bor

Nemanja Kaloper

A no-go theorem pertaining to the graceful exit problem in Pre-Big-Bang inflation is reviewed. It is shown that dilaton self-interactions and string fluid sources fail to facilitate branch changing necessary to avoid singularities. A comment on the failure of the higher genus corrections to induce graceful exit is also included.

Rafael D. Sorkin

We treat two aspects of the physics of stationary black holes. First we prove that the proportionality, d(energy) ~ d(area) for arbitrary perturbations (``extended first law&#39;&#39;), follows directly from an extremality theorem drawn from earlier work. Second we consider quantum fluctuations in the shape of the horizon, concluding heuristically that they

Johannes Kellendonk

The local structure of a tiling is described in terms of a multiplicative structure on its pattern classes. The groupoid associated to the tiling is derived from this structure and its integer group of coinvariants is defined. This group furnishes part of the $K_0$-group of the groupoid $C^*$-algebra for tilings which reduce to decorations of $\Z^d$. The gro

T. V. Shahbazyan, M. E. Raikh

We study the effect of interactions on the zero-temperature a.c. conductivity of 2D Anderson insulator at low frequencies. We show that the enhancement of the real part of conductivity due to the Coulomb correlations in the occupation numbers of localized states results in the change of the sign of imaginary part within a certain frequency range. As a result

Daniel D. K. Sleator, Davy Temperley

We develop a formal grammatical system called a link grammar, show how English grammar can be encoded in such a system, and give algorithms for efficiently parsing with a link grammar. Although the expressive power of link grammars is equivalent to that of context free grammars, encoding natural language grammars appears to be much easier with the new system

Dennis Grinberg, John Lafferty, Daniel Sleator

In this paper we present a robust parsing algorithm based on the link grammar formalism for parsing natural languages. Our algorithm is a natural extension of the original dynamic programming recognition algorithm which recursively counts the number of linkages between two words in the input sentence. The modified algorithm uses the notion of a null link in

Johan Bos, Paul Buitelaar, Anne-Marie Mineur

In this paper we discuss the notion of &#34;bridging&#34; in Discourse Representation Theory as a tool to account for discourse referents that have only been established implicitly, through the lexical semantics of other referents. In doing so, we use ideas from Generative Lexicon theory, to introduce antecedents for anaphoric expressions that cannot be &#34

Aurel Bulgac, Caio Lewenkopf, Vadim Mickrjukov

A new method to obtain a local parameterization for the exchange term in the many--body electronic problem is presented. The approach amounts to the introduction of a coordinate dependent electron effective mass. Numerical results for metallic clusters in the jellium model are compared with other standard methods.

David Schade, David Crampton, F. Hammer, O. Le Fevre

Six objects with broad emission lines and redshifts from 0.48 to 2.07 were discovered among 736 extragalactic objects in the Canada-France Redshift Survey (CFRS). Although the luminosities of half of the objects are such that they are in the Seyfert regime (M_B > -23), all would be designated as quasars in traditional surveys. Since the only selection criter

Bruce Hunt

Arithmetic quotients are quotients of bounded symmetric domains by arithmetic groups, and modular subvarieties of arithmetic quotients are themselves arithmetic quotients of lower dimension which live on arithmetic quotients, by an embedding induced from an inclusion of groups of hermitian type. We show the existence of such modular subvarieties, drawing on

Thorsten Poeschel, Volkhard Buchholtz

We propose a new model for the description of complex granular particles and their interaction in molecular dynamics simulations of granular material in two dimensions. The grains are composed of triangles which are connected by deformable beams. Particles are allowed to be convex or concave. We present first results of simulations using this particle model.

D. Gabrielli, G. Jona-Lasinio, C. Landim

In this paper we show that Onsager--Machlup time reversal properties of thermodynamic fluctuations and Onsager reciprocity relations for transport coefficients can hold also if the microscopic dynamics is not reversible. This result is based on the explicit construction of a class of conservative models which can be analysed rigorously.

Sh. Fujita, H. Nishimura

A locally iterative learning (LIL) rule is adapted to a model of the associative memory based on the evolving recurrent-type neural networks composed of growing neurons. There exist extremely different scale parameters of time, the individual learning time and the generation in evolution. This model allows us definite investigation on the interaction between

Adam K. Leibovich, Aneesh V. Manohar, Mark B. Wise

We predict differential decay distributions for phi->rho gamma gamma and phi -> omega gamma gamma using chiral perturbation theory. We also consider the isospin violating decay phi -> omega pi^0. Experimental information on these decays can be used to determine couplings in the heavy vector meson chiral Lagrangian.

M. S. Berger

The beam energy spread is a major issue in future attempts to study the $t\overline{t}$ threshold at $e^+e^-$ colliders. Muon colliders are expected to naturally have narrow band beams making them an ideal place to study the excitation curve. We present the parameter determinations that are possible from measuring the total cross section near threshold at a

Dan Edidin, William Graham

The purpose of this paper is to prove the localization theorem for torus actions in equivariant intersection theory. Using the theorem we give another proof of the Bott residue formula for Chern numbers of bundles on smooth complete varieties. In addition, our techniques allow us to obtain residue formulas for bundles on a certain class of singular schemes w

Nick Evans, Stephen D. H. Hsu, Myckola Schwetz, Stephen B. Selipsky

We give an explicit formalism connecting softly broken supersymmetric gauge theories (with QCD as one limit) to $N=2$ and $N=1$ supersymmetric theories possessing exact solutions, using spurion fields to embed these models in an enlarged $N=1$ model. The functional forms of effective Lagrangian terms resulting from soft supersymmetry breaking are constrained

Changhyun Ahn, E. Ivanov, A. Sorin

We construct N=2 affine current algebras for the superalgebras sl(n|n-1)^{(1)} in terms of N=2 supercurrents subjected to nonlinear constraints and discuss the general procedure of the hamiltonian reduction in N=2 superspace at the classical level. We consider in detail the simplest case of N=2 sl(2|1)^{(1)} and show how N=2 superconformal algebra in N=2 sup

Juan Garcia-Bellido, Andrew R Liddle, David H Lyth, David Wands

The Grishchuk--Zel&#39;dovich effect is the contribution to the microwave background anisotropy from an extremely large scale adiabatic density perturbation, on the standard hypothesis that this perturbation is a typical realization of a homogeneous Gaussian random field. We analyze this effect in open universes, corresponding to density parameter $Ω_0<1$ wi

J. Ambjørn, A. Krasnitz

Results of a large scale numerical simulation show that the high temperature Chern-Simons number diffusion rate in the electroweak theory has a classical limit $Γ= κ(α_w T)^4$, where $κ= 1.09\pm 0.04$ and $α_w$ is the weak fine structure constant.

E. Quack, P. A. Henning

In-medium interactions of a particle in a hot plasma are considered in the framework of thermal field theory. The formalism to calculate gauge invariant rates for photon and dilepton production from the medium is given. In the application to a QED plasma, astrophysical consequences are pointed out. The photon production rate from strongly interacting quarks

Hisao Suzuki

Recently proposed mechanism of the black hole condensation at conifold singularity in type II string is an interesting idea from which we can interpret the phase of the universal moduli space of the string vacua. It might also be expected that the true physics is on the conifold singularity after supersymmetry breaking. We derive a mass formula for the extre

Bob Bailey

New distributions are presented which allow di-photon + jet events to be clearly separated into three classes of events based on the $p_{T}$ of the final state particles and their separation $R$ = $\sqrt{(Δy)^{2} + (Δϕ)^{2}}$. The analysis used can easily be extended to the case of di-jet + photon.

Vincent Pasquier

We construct the scattering matrices for an arbitrary Weyl group in terms of elementary operators which obey the generalised Yang-Baxter equation. We use this construction to obtain the affine Hecke algebras. The center of the affine Hecke algebras coincides with commuting Hamiltonians. These Hamiltonians have q-deformed affine Lie algebras as symmetry algeb

B. Jurco, M. Schlieker

Integrable systems on quantum groups are investigated. The Heisenberg equations possessing the Lax form are solved in terms of the solution to the factorization problem on the corresponding quantum group.

K. Kubodera, F. Myhrer, Th. Meissner, R. Morones

We discuss two topics concerning the application of chiral perturbation theory to nuclear physics: (1) the latest developments in the study of possible kaon condensation in dense baryonic systems; (2) nuclear responses to electro-weak probes.

P. A. Henning, Ch. Hoelbling, M. Blasone, L. V. Razumov

Two-particle correlation functions are calculated for bosons emitted from a localized thermal source (the ``glow&#39;&#39; of a ``hot spot&#39;&#39;). In contrast to existing work, non-equilibrium effects up to first order in gradients of the particle distribution function are taken into account. The spectral width of the bosons is shown to be an important q

K. Hagino, N. Takigawa, M. Abe

Using Langer&#39;s $Im F$ method, we discuss the temperature dependence of nuclear fission width in the presence of dissipative environments. We introduce a low cut-off frequency to the spectral density of the environmental oscillators in order to mimic the pairing gap. It is shown that the decay width rapidly decreases at the critical temperature, where the

H. Kouno, T. Mitsumori, K. Koide, N. Noda

The relation among the volume coefficient $K$(=incompressibility of the nuclear matter), the Coulomb coefficient $K_c$, and the volume-symmetry coefficient $K_{vs}$ of the nucleus incompressibility are studied in the framework of the relativistic mean field theory with the excluded volume effects of the nucleons, under the assumption of the scaling model. It

Zhu-Pei Shi, Barry M. Klein

The Anderson model of local-state conduction electron mixing is applied to the p roblem of interlayer magnetic coupling in metallic multilayered structures with palladium (Pd) spacer layers. An oscillation period of $5$ spacer monolayers and the tendency towards ferromag netic bias of the interlayer magnetic coupling that we obtain are consistent with the ex