August 1997 arXiv papers — page 2

Jarmo Hietarinta

The correspondence between the integrability of classical mechanical systems and their quantum counterparts is not a 1-1, although some close correspondencies exist. If a classical mechanical system is integrable with invariants that are polynomial in momenta one can construct a corresponding commuting set of differential operators. Here we discuss some 2- o

E. J. Copeland, James E. Lidsey, David Wands

We discuss the symmetry properties of the low-energy effective action of the type IIB superstring that may be employed to derive four-dimensional solutions. A truncated effective action, compactified on a six-torus, but including both Neveu/Schwarz-Neveu/Schwarz and Ramond-Ramond field strengths, can be expressed as a non-linear sigma model which is invarian

T. Feuster, U. Mosel

In an effective Lagrangian model employing the K-matrix approximation we extract nucleon resonance parameters. To this end we analyze simultaneously all available data for reactions involving the final states $πN$, $ππN$, $ηN$ and $K Λ$ in the energy range $m_N + m_π \le \sqrt s \le 1.9$ GeV. The background contributions are generated consistently from the r

Yas-Hiro Quano

We present new expressions of form factors of the XXZ model which satisfy Smirnov's three axioms. These new form factors are obtained by acting the affine quantum group $U_q (\hat{\frak s \frak l_2})$ to the known ones obtained in our previous works. We also find the relations among all the new and known form factors, i.e., all other form factors can be

Paul Benioff

Quantum Turing machines are discussed and reviewed in this paper. Most of the paper is concerned with processes defined by a step operator $T$ that is used to construct a Hamiltonian $H$ according to Feynman's prescription. Differences between these models and the models of Deutsch are discussed and reviewed. It is emphasized that the models with $H$ con

J. Audretsch, M. Mensky, V. Namiot

The previously proposed visualization of Rabi oscillations of a single atom by a continuous fuzzy measurement of energy is specified for the case of a single transition between levels caused by a $π$-pulse of a driving field. An analysis in the framework of the restricted-path-integral approach (which reduces effectively to a Schrödinger equation with a comp

Ramandeep S. Johal

We cast the $q$-rotor in the framework of Barnett-Pegg theory for rotation angle, whose underlying algebra is $SU_q(2)$. A new method to fix the deformation parameter from the theory is suggested. We test our ideas by fitting rotational spectra in deformed even-even and superdeformed nuclei. The results are in good agreement with the previous phenomenologica

R. L. Bates, M. Campbell, C. Da'Via, S. D'Auria

The present understanding of the charge collection in GaAs detectors with respect to the materials used and its processing are discussed. The radiation induced degradation of the charge collection efficiency and the leakage current of the detectors are summarised. The status of strip and pixel detectors for the ATLAS experiment are reported along with the la

R. L. Bates, C. Da'Via, S. D'Auria, V. O'Shea

Semi-insulating, undoped, Liquid Encapsulated Czochralski (SI-U LEC) GaAs detectors have been irradiated with 1MeV neutrons, 24GeV/c protons, and 300MeV/c pions. The maximum fluences used were 6, 3, and 1.8~10$^{14}$ particles/cm$^{2}$ respectively. For all three types of irradiation the charge collection efficiencies (cce) of the detector are reduced due to

R. L. Bates, C. Da'Via, V. O'Shea, C. Raine

GaAs Schottky diode detectors have been fabricated upon Low Pressure Vapour Phase Epitaxial GaAs. The devices were characterised before and after a $1.25 \times 10^{14}$~cm$^{-2}$ 24GeV/c proton fluence. The as fabricated Ti-GaAs barrier height was measured, via two electrical methods, to be $0.81\pm0.005$ and $0.85\pm0.01$~eV and a space charge density of $

Bin Zhang, Yang Pang, Miklos Gyulassy

Kinetic theory is used to check the applicability of parton cascade in 1 dimensional expansion. Using the information provided by 3 dimensional parton cascade, we model the transverse expansion by an effective area. With this model, kinetic theory is able to give prediction of the time development of transverse energy which is in good agreement with the part

Simon Capstick, D. Robson

We report on the contributions to the nucleon weak magnetic and electric form factors arising from isospin-breaking form factors. The relativized quark model used in the calculations includes isospin impurities in the large basis nucleon wavefunctions and uses constituent quark currents with both Pauli and Dirac components. Significant contributions are foun

S. G. Matinyan, B. Mueller, D. H. Rischke

We investigate the space-time structure of the classical gluon field produced in an ultrarelativistic collision between color charges. The classical solution which was computed previously in a perturbative approach is shown to become unstable on account of the non-Abelian self-interaction neglected in the perturbative solution scheme. The time scale for grow

R. Bijker, A. Leviatan

We consider an algebraic treatment of a three-body system. We develop the formalism for a system of three identical objects and show that it provides a simultaneous description of the vibrational and rotational excitations of an oblate symmetric top.

G. Kälbermann

The energy levels of a skyrmion in nucleus are calculated in a field theory of skyrmions coupled to the dilaton field and the $ω$ meson . The central potential fits well with expectations. The nucleon spin-orbit interaction derived from the omega meson in a rotating frame gives the correct level splittings. The same interaction originating from the Thomas pr

Akihiko Yukie

In this note, we prove that if $(G,V)$ is a prehomogeneous vector space over any field $k$ such that the stabilizer of a generic point is reductive, the set of semi-stable points is a single orbit over the separable closure of $k$.

Haskell P. Rosenthal

In 1955, A.~Grothendieck proved a basic inequality which shows that any bounded linear operator between $L^1(μ)$-spaces maps (Lebesgue-) dominated sequences to dominated sequences. An elementary proof of this inequality is obtained via a new decomposition principle for the lattice of measurable functions. An exposition is also given of the M.~Lévy extension

Matthew G. Brin, Fernando Guzman

We look at the automorphisms of Thompson type groups of piecewise linear homeomorphisms of the real line or circle that use slopes that are integral powers of a fixed integer n with n>2. We show that large numbers of "exotic" automorphisms appear---automorphisms that are represented as conjugation by non-PL homeomorphisms of the real line or circle.

Liviu Tatar, Radu Tatar

The anti-BRST transformation, in its Sp(2)-symmetric version, for the general case of any stage-reducible gauge theories is implemented in the usual BV approach. This task is accomplished not by duplicating the gauge symmetries but rather by duplicating all fields and antifields of the theory and by imposing the acyclicity of the Koszul-Tate differential. In

J. A. Briginshaw

The aim of this article is to calculate (to first order in $\hbar$) the renormalized effective action of a self interacting massive scalar field propagating in the space-time due to a cylindrically symmetric, rotating body. The vacuum (exterior space-time) contribution is model independent, we also consider the simplest case of a core (interior space-time) m

V. D. Ivashchuk, V. N. Melnikov

Multidimensional cosmological model describing the evolution of n+1 Einstein spaces in the theory with several scalar fields and forms is considered. When a (electro-magnetic composite) p-brane Ansatz is adopted the field equations are reduced to the equations for Toda-like system. The Wheeler-De Witt equation is obtained. In the case when n "internal&#3

Guang-Jiong Ni

Basing on the fundamental symmetry that the space-time inversion is equivalent to particle-antiparticle transformation, a relativistic modification on the stationary Schrodinger equation for many-particle system is made. The eigenvalue in the center of mass system is no longer equal to the negative of binding energy simply. The possible applications in vario

Guang-jiong Ni, Su-qing Chen

The effective potential of $λϕ^4_{1+3}$ model with both sign of parameter $m^2$ is evaluated at T=0 by means of a simple but effective method for regularization and renormalization. Then at $T\ne 0$, the effective potential is evaluated in imaginary time Green Function approach, using the Plana formula. A critical temperature for restoration of symmetry brea

E. J. Copeland, James E. Lidsey, David Wands

The continuous and discrete symmetries of a dimensionally reduced type IIB superstring action are employed to generate four-dimensional cosmological solutions with non-trivial Neveu-Schwarz/Neveu-Schwarz and Ramond-Ramond form-fields from the dilaton-moduli-vacuum solutions.

Anton E. M. van de Ven

Using index-free notation, we present the diagonal values of the first five heat kernel coefficients associated with a general Laplace-type operator on a compact Riemannian space without boundary. The fifth coefficient appears here for the first time. For a flat space with a gauge connection, the sixth coefficient is given too. Also provided are the leading

S. M. Klishevich

In this paper, for massive fields of spins 2 and 3 with non-canonical Lagrangians, we build Hamiltonians and full systems of constraints and show that the use of derivatives in a redefinition of fields can give rise to a change of number of physical degrees of freedom.

S. M. Klishevich, Yu. M. Zinoviev

In this work we construct a gauge invariant description of free massive particle with an arbitrary integer spin. Such description allows one to investigate the problem of consistent interactions for massive high spin particles using the requirement that the whole interaction Lagrangian must be gauge invariant. As a first example of such approach, we consider

Dongsu Bak, Choonkyu Lee, Kimyeong Lee

Based on a detailed analysis of nonlinear field equations of the SU(2) Yang-Mills-Higgs system, we obtain the effective field theory describing low-energy interaction of BPS dyons and massless particles (i.e., photons and Higgs particles). Our effective theory manifests electromagnetic duality and spontaneously broken scale symmetry, and reproduces the multi

Francesco Vissani

Motivated by cosmological considerations, and by the atmospheric and solar neutrino flux deficits, we consider the scenario in which the three Standard Model neutrinos are endowed with a nearly equal Majorana mass in the eV range. Combined constraints coming from (1) direct search for electron neutrino mass, (2) absence of neutrinoless double beta decay, and

Peter Van Alstine, Horace W. Crater

G.Breit's original paper of 1929 postulates the Breit equation as a correction to an earlier defective equation due to Eddington and Gaunt, containing a form of interaction suggested by Heisenberg and Pauli. We observe that manifestly covariant electromagnetic Two-Body Dirac equations previously obtained by us in the framework of Relativistic Constraint

D. V. Shirkov

We discuss the model $\barα_{an}(Q^2)$ recently proposed for the QCD running coupling $\barα_s(Q^2)$ in the Euclidean domain on the basis of the "asymptotic-freedom" expression and on causality condition in the form of the $Q^2$-analyticity. The model contains no adjustable parameters and obeys the important features: (i) Finite ghost-free behavior i

Sourendu Gupta, Prakash Mathews

We study the unpolarised and polarised hadro-production of charmonium in non-relativistic QCD (NRQCD) at low transverse momentum, including sufficiently higher orders in the relative velocity, $v$, so as to study the ratio of $χ_{c1}$ and $χ_{c2}$ production rates.

UKQCD Collaboration, L Del Debbio, J M Flynn, L Lellouch

We describe the form factors for semileptonic B to rho l nu and radiative B to K* gamma decays with just two parameters and the two form factors for semileptonic B to pi l nu decays with three parameters. The parametrizations are constrained by lattice results and are consistent with heavy quark symmetry, kinematic constraints and light cone sum rule scaling

E791 Collaboration

This paper presents measurements of the production of Ds- mesons relative to Ds+ mesons as functions of x_F and square of p_t for a sample of 2445 Ds decays to phi pi. The Ds mesons were produced in Fermilab experiment E791 with 500 GeV/c pi- mesons incident on one platinum and four carbon foil targets. The acceptance-corrected integrated asymmetry in the x_

L. P. Grishchuk

The quantum gravity processes that have taken place in the very early Universe are probably responsible for the observed large-scale cosmological perturbations. The comparison of the theory with the detected microwave background anisotropies favors the conclusion that the very early Universe was not driven by a scalar field with whichever scalar field potent

Sebastiano Sonego, Marco Bruni

Diffeomorphism freedom induces a gauge dependence in the theory of spacetime perturbations. We derive a compact formula for gauge transformations of perturbations of arbitrary order. To this end, we develop the theory of Taylor expansions for one-parameter families (not necessarily groups) of diffeomorphisms. First, we introduce the notion of knight diffeomo

Ying Shen, Rugang Ye

We introduce some new curvature quantities such as conformal Ricci curvature and bi-Ricci curvature and extend the classical Myers theorem under these new curvature conditions. Moreover, we are able to obtain the Myers type theorem for minimal submanifolds in ambient manifolds with positive bi-Ricci curvature. Some topological applications are discussed. We

Per Jögi, Didier Sornette, Michael Blank

Discrete scale invariance (DSI) has recently been documented in time-to-failure rupture, earthquake processes and financial crashes, in the fractal geometry of growth processes and in random systems. The main signature of DSI is the presence of log-periodic oscillations correcting the usual power laws, corresponding to complex exponents. Log-periodic structu

C. Solterbeck, W. Schattke, J. -W. Zahlmann-Nowitzki, K. -U. Gawlik

Angle-resolved ultraviolet photoemission spectra are interpreted by combining the energetics and spatial properties of the contributing states. One-step calculations are in excellent agreement with new azimuthal experimental data for GaAs(110). Strong variations caused by the dispersion of the surface bands permit an accurate mapping of the electronic struct

Stefan Schinzer, Wolfgang Kinzel

Solid-On-Solid (SOS) computer simulations are employed to investigate the sublimation of surfaces. We distinguish three sublimation regimes: layer-by-layer sublimation, free step flow and hindered step flow. The sublimation regime is selected by the morphology i.e. the terrace width. To each regime corresponds another effective energy. We propose a systemati

C. -H. Pao, H. -B. Schüttler

We have studied the d-wave pairing-instability in the two-dimensional Holstein-Hubbard model at the level of a full fluctuation exchange approximation which treats both Coulomb and electron-phonon (EP) interaction diagrammatically on an equal footing. A generalized numerical renormalization group technique has been developed to solve the resulting self-consi

U. Bastolla, G. Parisi

The statistical properties of the length of the cycles and of the weights of the attraction basins in fully asymmetric neural networks (i.e. with completely uncorrelated synapses) are computed in the framework of the annealed approximation which we previously introduced for the study of Kauffman networks. Our results show that this model behaves essentially

U. Bastolla, G. Parisi

This is the second paper of a series of two about the structural properties that influence the asymptotic dynamics of Random Boolean Networks. Here we study the functionally independent clusters in which the relevant elements, introduced and studied in our first paper, are subdivided. We show that the phase transition in Random Boolean Networks can also be d

U. Bastolla, G. Parisi

This is the first of two papers about the structure of Kauffman networks. In this paper we define the relevant elements of random networks of automata, following previous work by Flyvbjerg and Flyvbjerg and Kjaer, and we study numerically their probability distribution in the chaotic phase and on the critical line of the model. A simple approximate argument

Peter Hoppe, Gernot Münster

In liquid mixtures and other binary systems at low temperatures the pure phases may coexist, separated by an interface. The interface tension vanishes according to $σ= σ_0 (1 - T/T_c)^μ$ as the temperature T approaches the critical point from below. Similarly the correlation length diverges as $ξ= f_- (1 - T/T_c)^{-ν}$ in the low temperature region. For thre

Jean M. Quashnock, Daniel E. Vanden Berk

We have analyzed the clustering of C IV and Mg II absorption-line systems on comoving scales from 1 to 16 \hMpc, using an extensive catalog of heavy-element QSO absorbers with mean redshift 2.2 (C IV) and 0.9 (Mg II). For the C IV sample as a whole, the absorber line-of-sight correlation function is well fit by a power law of the form $ξ(r)=(r_0/r)^γ$, with

Andrew Ulmer

Geometrically thick disks may form after tidal disruption events, and rapid accretion may lead to short flares followed by long-term, lower-level emission. Using a novel accretion disk code which relies primarily on global conservation laws and the assumption that viscosity is everywhere positive, a broad range of physically allowed evolutionary sequences of

Andrew Ulmer, Edward L. Fitzpatrick

We have determined the location of the line-opacity modified Eddington limit for stars in the LMC using the most recent atmosphere models combined with a precise mapping to the HR Diagram through up-to-date stellar evolution calculations. While we find, in agreement with previous studies, that the shape of the modified Eddington limit qualitatively correspon

Timothy M. Heckman

Starbursts are episodes of intense star-formation that occur in the central regions of galaxies, and dominate the integrated emission from the galaxy. They are a significant component of the present- day universe, being the site of $\sim$ 25% of the high-mass star- formation. They offer unique `laboratories' for testing our ideas about star-formation, th

J. M. Marcaide, A. Alberdi, E. Ros, P. Diamond

A rarity among supernova, SN 1993J in M81 can be studied with high spatial resolution. Its radio power and distance permit VLBI observations to monitor the expansion of its angular structure. This radio structure was previously revealed to be shell-like and to be undergoing a self-similar expansion at a constant rate. From VLBI observations at the wavelength

Marek Sikora, Greg Madejski, Mitchell Begelman

Simultaneous observations of blazars in different spectral regimes imply that the amplitude of variability depends on the observational band. Both in the low energy spectral component and in the high energy spectral component, the amplitude increases with the photon energy. We show that such behavior can be explained in terms of a two-component model, where

M. Guainazzi, L. Piro

In the following paper, some first Beppo-SAX results on AGN are presented. Main on-flight calibration features and observational properties are discussed at the light of possible future AGN studies

Helen Tadros, George Efstathiou, Gavin Dalton

We present an analysis of the redshift-space power spectrum, $P(k)$, of rich clusters of galaxies based on an automated cluster catalogue selected from the APM Galaxy Survey. We find that $P(k)$ can be approximated by a power law, $P(k)\proptok^{n}$, with $n\approx-1.6$ over the wavenumber range $0.04\hr<k<0.1\hr$. Over this range of wavenumbers, the APM clu

Marek Sikora

We present an overview of the current theoretical models attempting to describe the structure and radiative processes operating in blazars and discuss the observational constraints that these models must confront.

Michael R. Meyer, S. V. W. Beckwith, T. M. Herbst, M. Robberto

We report mid--IR observations of two young stars found in the Taurus dark cloud spatially resolving for the first time their 10 $μ$m emission. The weak-emission T Tauri star DI Tau, tentatively identified by Skrutskie et al. (1990) on the basis of 12 $μ$m IRAS data as an object in the process of dissipating its circumstellar disk, is found to have no infrar

Maxim Kontsevich, Yuri I. Manin

We prove a new recursive relation between the correlators $< τ_{d_1}γ_1...τ_{d_n}γ_n >_{g,β}$, which together with known relations allows one to express all of them through the full system of Gromov-Witten invariants in the sense of Kontsevich-Manin and the intersection indices of tautological classes on $\bar{M}_{g,n}$, effectively calculable in view of ear

Hirotachi Abo, Wolfram Decker, Nobuo Sasakura

In this note we show the existence of a family of elliptic conic bundles in P^4 of degree 8. This family has been overlooked and in fact falsely ruled out in a series of classification papers. Our surfaces provide a counterexample to a conjecture of Ellingsrud and Peskine. According to this conjecture there should be no irregular m-ruled surface in P^4 for m

Curtis G. Callan,, Juan M. Maldacena

We use the abelian Born-Infeld action for the worldvolume gauge field and transverse displacement scalars to explore new aspects of D-brane structure and dynamics. We study several classic gauge field configurations, including point charges in any worldvolume dimension and vortices in two worldvolume dimensions, and show that, with an appropriate excitation

Meinrad Hafner, Johann Summhammer

A neutron interferometric test of interaction-free detection of the presence of an absorbing object in one arm of a neutron interferometer has been performed. Despite deviations from the ideal performance characteristics of a Mach-Zehnder interferometer it could be shown that information is obtained without interaction.

Johann Summhammer

The scheme of Clauser and Dowling (Phys. Rev. A 53, 4587 (1996)) for factoring $N$ by means of an N-slit interference experiment is translated into an experiment with a single Mach-Zehnder interferometer. With dispersive phase shifters the ratio of the coherence length to wavelength limits the numbers that can be factored. A conservative estimate permits $N

De-Hone Lin

The path integral for relativistic three-dimensional spinless Aharonov-Bohm-Coulomb system is solved, and the energy spectra are extracted from the resulting amplitude.

Fabian H. L. Essler, Alexei M. Tsvelik

Recent experiments on the quasi 1-D antiferromagnet Cu Benzoate revealed a magentic field induced gap coexisting with (ferro)magnetic order. A theory explaining these findings has been proposed by Oshikawa and Affleck. In the present work we discuss consequences of this theory for inelastic neutron scattering experiments by calculating the dynamical magnetic

Tomoya Isoshima, Kazushige Machida

Various widely-used mean-field type theories for a dilute Bose gas are critically examined in the light of the recent discovery of Bose-Einstein condensation of atomic gases in a confined geometry. By numerically solving the mean-field equations within the framework of the Bogoliubov approximation both stationary non-uniform case and the vortex case under ro

Pedro T P Viana, Andrew R Liddle

Structure formation models with a cosmological constant are successful in explaining large-scale structure data, but are threatened by the magnitude-redshift relation for Type Ia supernovae. This has led to discussion of models where the cosmological `constant' decays with time, which might anyway be better motivated in a particle physics context. The simple

Andre Rouge

The construction of the complete isospin relations and inequalities between the possible charge configurations of a $τ\to K\bar Knπν$ decay mode is presented. Detailed applications to the cases of two and three pions are given.

Masaaki Nakamura, Kiyohide Nomura, Atsuhiro Kitazawa

We study the spin-gap phase in the one-dimensional t-J model, assuming that it is caused by the backward scattering process. Based on the renormalization group analysis and symmetry, we can determine the transition point between the Tomonaga-Luttinger liquid and the spin-gap phases, by the level crossing of the singlet and the triplet excitations. In contras

Jean-Pierre Eckmann, Itamar Procaccia

Irreversible thermodynamics of simple fluids have been connected recently to the theory of dynamical systems and some interesting assumptions have been made about the nature of the associated invariant measures. We show that the tests of validity of these assumptions are insufficient by exhibiting observables that are incorrectly sampled with the proposed in

I. A. Batalin, K. Bering, P. H. Damgaard

We present a superfield formulation of the quantization program for theories with first class constraints. An exact operator formulation is given, and we show how to set up a phase-space path integral entirely in terms of superfields. BRST transformations and canonical transformations enter on equal footing, and they allow us to establish a superspace analog

N. K. Fedorov

Increasing of electronic thermal conductivity of superconductor in the model with nontrivial density of states was considered. The electronic thermal conductivity K(T) of SC in the presence of external magnetic field was investigated. It was shown that if symmetrical part of quasiparticle scattering rate less than cyclotron energy observed mechanism of incre

EOS Collaboration, M. Justice, S. Albergo, F. Bieser

A sample of Lambda&#39;s produced in 2 A*GeV Ni + Cu collisions has been obtained with the EOS Time Projection Chamber at the Bevalac. Low background in the invariant mass distribution allows for the unambiguous demonstration of Lambda directed flow. The transverse mass spectrum at mid-rapidity has the characteristic shoulder-arm shape of particles undergoin

R. J. Hughes, D. F. V. James, J. J. Gomez, M. S. Gulley

The development and theory of an experiment to investigate quantum computation with trapped calcium ions is described. The ion trap, laser and ion requirements are determined, and the parameters required for quantum logic operations as well as simple quantum factoring are described.

S. Chaturvedi, R. MacKenzie, P. K. Panigrahi, V. Srinivasan

It is shown that the grand partition function of an ideal Bose system with single particle spectrum $ε_i = (2n+k+3/2)\hbarω$ is identical to that of a system of particles with single particle energy $ε_i =(n+1/2)\hbarω$ and obeying a particular kind of statistics based on the permutation group.

A. S. Holevo

The more than thirty years old issue of the information capacity of quantum communication channels was dramatically clarified during the last period, when a number of direct quantum coding theorems was discovered. To considerable extent this progress is due to an interplay between the quantum communication theory and quantum information ideas related to more

Gyula Bene

A new interpretation offers a consistent conceptual basis for nonrelativistic quantum mechanics. The Einstein-Podolsky-Rosen (EPR) paradox is solved and the violation of Bell&#39;s inequality is explained by maintaining realism, inductive inference and Einstein separability.

Constantinos Tzanakis, Alkis P. Grecos

The probabilistic description of finite classical systems often leads to linear kinetic equations. A set of physically motivated mathematical requirements is accordingly formulated. We show that it necessarily implies that solutions of such a kinetic equation in the Heisenberg representation, define Markov semigroups on the space of observables. Moreover, a

Martin J. Savage, Roxanne P. Springer

We calculate the leading contribution to the weak $ΛΛK$ coupling in heavy baryon chiral perturbation theory, including the SU(3) breaking terms arising at one-loop. This coupling gives the leading one-boson exchange amplitude for the process $ΛΛ\toΛn$ and is an important component in understanding the decay of $ΛΛ$-hypernuclei. We find the S-wave and P-wave

Simon Capstick, W. Roberts

The decays of excited nonstrange baryons into the final states Delta eta and Delta omega are examined in a relativized quark pair creation model. The wavefunctions and parameters of the model are fixed by previous calculations of N pi and N pi pi, etc., decays through various quasi-two body channels including N eta and N omega. Our results show that the comb

V. S. Uma Maheswari, C. Fuchs, Amand Faessler, Z. S. Wang

The importance of a isospin dependent nuclear mean field (IDMF) in regard to the pion production mechanism is studied for the reaction $Au+Au$ at 1 GeV/nucleon using the Quantum Molecular Dynamics (QMD) model. In particular, the effect of the IDMF on pion spectra and the charged pion ratio are analyzed. It is found that the inclusion of a IDMF considerably s

Gerald. A. Miller

A light front field theory treatment of a chiral lagrangian is applied to pion-nucleon and nucleon-nucleon scattering.

N. N. Scoccola, D. R. Bes

We study a model for two-dimensional skyrmions on a sphere of radius L. Such model simulates a skyrmion lattice of density W/(2 \pi L^2), where W is the skyrmion winding number. We show that, to a very good approximation, physical results depend only on the product \alpha L^4, where \alpha is the strength of potential term. In the range \alpha L^4 approx. or

Anastasia Doikou, Luca Mezincescu, Rafael I. Nepomechie

We compute by means of the Bethe Ansatz the boundary S matrix for the open anisotropic spin-1/2 chain with diagonal boundary magnetic fields in the noncritical regime (Delta > 1). Our result, which is formulated in terms of q-gamma functions, agrees with the vertex-operator result of Jimbo et al.

S. James Gates,

We show how the usual chiral perturbation theory description of phenomenological pion physics admits an interpretation as a low-energy string-like model associated with QCD. By naive and straightforward generalization within the context of a new class of supersymmetrical models, it is shown that this string-like structure admits a 4D, N = 1 supersymmetrical

J. C. Breckenridge

The black hole solutions to Einstein&#39;s vacuum field equations are also solutions to the equations of motion of the low energy limit of superstring theory. At the same time, string theory boasts a much broader and richer collection of black hole solutions. Fortunately, string theories also possess a remarkable set of duality symmetries relating states wit

J. Fuchs, C. Schweigert

We introduce a finite-dimensional algebra that controls the possible boundary conditions of a conformal field theory. For theories that are obtained by modding out a Z_2 symmetry (corresponding to a so-called D_odd-type, or half-integer spin simple current, modular invariant), this classifying algebra contains the fusion algebra of the untwisted sector as a

Shin&#39;ichi Nojiri, Sergei D. Odintsov

We construct the theory of 2d dilatonic supergravity(SG) with matter and dilaton supermultiplets coupled to dilaton functions. Trace anomaly and induced effective action for matter supermultiplet are calculated (what gives also large-N effective action for dilatonic SG). Study of black holes and Hawking radiation which turns out to be zero in supersymmetric

Susan Cartwright, Michael H Seymour, Klaus Affholderbach, Frank Close

The working group on two photon physics concentrated on three main subtopics: modelling the hadronic final state of deep inelastic scattering on a photon; unfolding the deep inelastic scattering data to obtain the photon structure function; and resonant production of exclusive final states, particularly of glueball candidates. In all three areas, new results

G. Hiller, E. O. Iltan

The B_{s} --> ϕψdecay is modeled through the inclusive b --> sψdecay. Using the Vector Meson Dominance model, the amplitude for the chain process B_{s} --> ϕψ--> ϕγ--> γγis estimated and it is found to be at most 4 % of the corresponding amplitude from the O_7 type LD contribution. The intermediate amplitude for the process B_{s} --> ϕγis compared with the c

David London

After reviewing the present experimental constraints on the unitarity triangle, I discuss the various ways in which new physics can manifest itself in measurements of the parameters of the unitarity triangle. Apart from one exception, which I describe, new physics enters principally through new contributions to B0-B0(bar) mixing. Different models of new phys

H. P. Shanahan

The classical transitions between topologically distinct vacua in a SU(2)-Higgs model, using a Higgs field of mass approximately 120 GeV, is examined to probe the crossover region between the symmetric and broken phase. For the volumes used, this crossover is approximately 10 GeV wide.

G. Bottazzi

We examine the effect of using an angular ordered evolution equation for the unintegrated gluon distribution at small x.

K. J. Eskola

I discuss how the initial conditions for QGP-production in ultrarelativistic heavy ion collisions at the LHC and RHIC can be computed from perturbative QCD.

Lorenzo Magnea, Rodolfo Russo

We briefly review the technology involved in extracting the field-theory limit of multiloop bosonic string amplitudes, and we apply it to the evaluation of simple two-loop diagrams involving scalars and gauge bosons.

Mihoko M. Nojiri

In the case with a large splitting between the squark and slepton masses, the supersymmetric identities which enforce the equality of the gauge and gaugino couplings are violated in the effective theory below the squark mass threshold. We compute the full one-loop (s)quark corrected slepton production cross-sections. We find that the one-loop corrected slept

Ivan Horvath, A. D. Kennedy

We analyze the autocorrelations for the LHMC algorithm in the context of free field theory. In this case this is just Adler&#39;s overrelaxation algorithm. We consider the algorithm with even/odd, lexicographic, and random updates, and show that its efficiency depends crucially on this ordering of sites when optimized for a given class of operators. In parti

L. Del Debbio, M. Faber, J. Greensite, S. Olejnik

We present a variety of numerical data supporting the Center Vortex theory of confinement. A method is introduced for identifying the location of center vortices, in thermalized gauge-field configurations generated by lattice Monte Carlo. Fluctuations in the number of such vortices, linked to fundamental representation Wilson loops, appear to be responsible

R. Battiston

The AMS is a state of the art detector for extraterrestrial study of antimatter, matter and missing matter. After a precursor flight on STS91 in May 1998, AMS will be installed on the International Space Station where it will operate for three years. In this paper the AMS experiment is described and is physics potential reviewed.

ZEUS Collaboration

Events containing an isolated prompt photon with high transverse energy, together with a balancing jet, have been observed for the first time in photoproduction at HERA.The data were taken with the ZEUS detector, in a $γp$ centre of mass energy range 120--250 GeV. The fraction of the incoming photon energy participating in the production of the prompt photon

Mark A. Scheel, Thomas W. Baumgarte, Gregory B. Cook, Stuart L. Shapiro

We describe a numerical code that solves Einstein&#39;s equations for a Schwarzschild black hole in spherical symmetry, using a hyperbolic formulation introduced by Choquet-Bruhat and York. This is the first time this formulation has been used to evolve a numerical spacetime containing a black hole. We excise the hole from the computational grid in order to

Thorsten Brotz

We discuss black hole quantization in the Wheeler-DeWitt approach. Our consideration is based on a detailed investigation of the canonical formulation of gravity with special considerations of surface terms. Since the phase space of gravity for non-compact spacetimes or spacetimes with boundaries is ill-defined unless one takes boundary degrees of freedom in

C. -T. Liang, J. E. F. Frost, M. Pepper, D. A. Ritchie

We have measured the low-temperature transport properties of a T-shaped quantum dot. Replicated oscillations superimposed on one-dimensional conductance steps are observed. These structures are consistent with electron phase-coherent length resonance effects in the ballistic regime. Using a simple model, we suggest that both one-dimensional and two-dimension