November 1995 arXiv papers — page 12

M. Hasenbusch, R. R. Horgan

We investigate the continuum limit in $SO(N)$ Principal Chiral Models concentrating in detail on the $SO(4)$ model and its covering group SU(2)xSU(2). We compute the mass gap in terms of Lambda_MS and compare with the prediction of Hollowood of $m/Ł_\MS = 3.8716$. We use the finite-size scaling method of Lüscher et al. to deduce $m/Ł_\MS$ and find that for t

UKQCD Collaboration, presented by Peer Ueberholz

We present the calculation of the spectrum of baryons containing one heavy quark. Heavy baryon and meson mass splittings are computed and compared with experiment. We give preliminary results for the form factor $G_1$ for the semileptonic decay $ Λ_b \rightarrow Λ_c l \barν $ and investigate its flavour symmetry.

Steve Rippl, Henk van Elst, Reza Tavakol, David Taylor

We generalise the equations governing relativistic fluid dynamics given by Ehlers and Ellis for general relativity, and by Maartens and Taylor for quadratic theories, to generalised $f(R)$ theories of gravity. In view of the usefulness of this alternative framework to general relativity, its generalisation can be of potential importance for deriving analogou

M. O. Katanaev, W. Kummer, H. Liebl

Two dimensional gravity with torsion is proved to be equivalent to special types of generalized 2d dilaton gravity. E.g. in one version, the dilaton field is shown to be expressible by the extra scalar curvature, constructed for an independent Lorentz connection corresponding to a nontrivial torsion. Elimination of that dilaton field yields an equivalent tor

G. Giachetta, G. Sardanashvily

In case of the Einstein's gravitation theory and its first order Palatini reformulation, the stress-energy-momentum of gravity has been proved to reduce to the Komar superpotential. We generalize this result to the affine-metric theory of gravity in case of general connections and arbitrary Lagrangian densities invariant under general covariant transform

Sean A. Hayward

Imaginary time is often used in quantum tunnelling calculations. This article advocates a conceptually sounder alternative: complex lapse. In the ``3+1'' action for the Einstein gravitational field minimally coupled to a Klein-Gordon field, allowing the lapse function to be complex yields a complex action which generates both the usual Lorentzian the

J. A. S. Lima, A. S. M. Germano, L. R. W. Abramo

Some properties of cosmological models with matter creation are investigated in the framework of the Friedman-Robertson-Walker (FRW) line element. For adiabatic matter creation, as developed by Prigogine and coworkers, we derive a simple expression relating the particle number density $n$ and energy density $ρ$ which holds regardless of the matter creation r

M. C. Chang, Q. Niu

We have derived a new set of semiclassical equations for electrons in magnetic Bloch bands. The velocity and energy of magnetic Bloch electrons are found to be modified by the Berry phase and magnetization. This semiclassical approach is used to study general electron transport in a DC or AC electric field. We also find a close connection between the cyclotr

K. Moon, S. M. Girvin

In a recent experiment, Milliken {\em et al.} demonstrated possible evidence for a Luttinger liquid through measurements of the tunneling conductance between edge states in the $ν=1/3$ quantum Hall plateau. However, at low temperatures, a discrepancy exists between the theoretical predictions based on Luttinger liquid theory and experiment. We consider the p

Giuseppe Iannaccone, Bruno Pellegrini

In this paper we derive a formula for the density of states in the presence of inelastic scattering in the quantum well of a double barrier structure as a function of a characteristic time of the motion of electrons (namely, the round trip time in the well) and of transmission probabilities for the whole structure and for each barrier. In the model we use th

S. R. Shannon, T. C. Choy, R. J. Fleming

We present the results of a new perturbation calculation in polymer statistics which starts from a ground state that already correctly predicts the long chain length behaviour of the mean square end--to--end distance $\langle R_N^2 \rangle\ $, namely the solution to the 2~dimensional~(2D) Edwards model. The $\langle R_N^2 \rangle$ thus calculated is shown to

N. V. Prokof'ev, P. C. E. Stamp

We develop a mathematical description of the decoherence caused by "spin baths", such as nuclear spins or magnetic impurities. In contrast to the usual oscillator bath models of quantum environments, decoherence in the spin bath can occur without any dissipation. Given the almost ubiquitous presence of nuclear spins in nature, our results have import

Constantino Tsallis, Dirk Jan Bukman

The optimization of the usual entropy $S_1[p]=-\int du p(u) ln p(u)$ under appropriate constraints is closely related to the Gaussian form of the exact time-dependent solution of the Fokker-Planck equation describing an important class of normal diffusions. We show here that the optimization of the generalized entropic form $S_q[p]=\{1- \int du [p(u)]^q\}/(q

Per Dahlqvist

We compute the decay of the velocity autocorrelation function, the Lyapunov exponent and the diffusion constant for the Sinai billiard within the framework of dynamical zeta functions. The asymptotic decay of the velocity autocorrelation function is found to be $C(t) \sim c(R)/t$. The Lyapunov exponent for the corresponding map agrees with the conjectured li

Julio F. Navarro

High resolution N-body simulations show that the density profiles of dark matter halos formed in the standard CDM cosmogony can be fit accurately by scaling a simple ``universal'' profile. Regardless of their mass, halos are nearly isothermal over a large range in radius, but significantly shallower than $r^{-2}$ near the center and steeper than $r^{

J. -P. Kneib, R. S. Ellis, I. Smail, W. J. Couch

We present a striking new Hubble Space Telescope (HST) observation of the rich cluster Abell 2218 taken with the Wide-Field and Planetary Camera (WFPC2). HST's restored image quality reveals a sizeable number of gravitationally-lensed features in this cluster, significantly more than had been identified using ground-based telescopes. The brightest arcs a

Jordi Miralda-Escude, Renyue Cen, Jeremiah P. Ostriker, Michael Rauch

We model the $\lya$ forest in a spatially flat, CDM model with $Ω=0.4$, with an Eulerian hydrodynamic simulation, and find that the intergalactic, photoionized gas collapses into sheet-like and filamentary structures which produce absorption lines like those observed in the $\lya$ forest. A typical filament is $\sim 1 h^{-1} \mpc$ long with thickness $\sim 5

M. Postman, L. M. Lubin, J. E. Gunn, J. B. Oke

We present an optical/near IR selected catalog of 79 clusters distributed over an area of 5.1~square~degrees. The catalog was constructed from images obtained with the 4-Shooter CCD mosaic camera on the Hale 5m telescope operating in ``scan" mode. The survey, hereafter known as the Palomar Distant Cluster Survey (PDCS), was conducted in two broad band fi

Stacy McGaugh

I give analytic expressions for the relative number, luminosity, and mass density of disc galaxies as a function of surface brightness. These surface brightness distributions are asymmetric, with long tails to lower surface brightnesses. This asymmetry induces systematic errors in most determinations of the galaxy luminosity function. Galaxies of low surface

Andrzej M. Soltan, Guenther Hasinger, Roland Egger, Steve Snowden

Large-scale fluctuations of the X-ray background are investigated using the ROSAT All-Sky Survey. The autocorrelation function of the extragalactic background at 1 keV is determined at separations 0.1 - 40 deg. We detect a significant signal for separations < 6 deg, which is larger than previous upper limits. We analyse the cross-correlation between the angu

David P. Bennett, Sun Hong Rhie

We analyse the BATSE 3B catalog using the pair-matching statistic. This statistic counts only the burst pairs which may have originated from the same source, so it is less likely to yield false detections of ``repeating bursts&#34; than the nearest neighbor and correlation function statistics. Even in the ideal case when repeating is the only possible source

Stefan Müller-Stach

We describe a method to construct indecomposable classes in Bloch&#39;s higher Chow group $CH^2(X,1)$ on algebraic surfaces over the complex numbers via transcendental methods and apply it to obtain examples on K3-surfaces and some surfaces of general type.

Hiraku Nakajima

Various constructions of the affine Lie algebra action on the homology group of moduli spaces of instantons on 4-manifolds are discussed. The analogy between the local-global principle and the role of mass is also explained. The detailed proofs are given in separated papers \cite{Na-algebra,Na-Hilbert}.

Somendra M. Bhattacharjee, Avinash Khare

The exact solution of the two-dimensional Ising model by Onsager in 1944 represents one of the landmarks in theoretical physics. On the occassion of the fifty years of the exact solution, we give a historical review of this model. After briefly discussing the exact solution by Onsager, we point out some of the recent developments in this field. The exact sol

C. Anastopoulos

We investigate the effects of the gravitational field on the quantum dynamics of non-relativistic particles. We consider N non-relativistic particles, interacting with the linearized gravitational field. Using the Feynman - Vernon influence functional technique, we trace out the graviton field, to obtain a master equation for the system of particles to first

Viqar Husain

We give circularly symmetric solutions for null fluid collapse in 2+1-dimensional Einstein gravity with a cosmological constant. The fluid pressure $P$ and energy density $ρ$ are related by $P=kρ$ $(k\le 1)$. The long time limit of the solutions are black holes whose horizon structures depend on the value of $k$. The $k=1$ solution is the Banados-Teitelboim-

George Svetlichny

Given the collapse hypothesis (CH) of quantum measurement, EPR-type correlations along with the hypothesis of the impossibility of superluminal communication (ISC) have the effect of globalizing gross features of the quantum formalism making them universally true. In particular, these hypotheses imply that state transformations of density matrices must be li

C. A. A. de Carvalho, R. M. Cavalcanti

We use path-integrals to derive a general expression for the semiclassical approximation to the partition function of a one-dimensional quantum-mechanical system. Our expression depends solely on ordinary integrals which involve the potential. For high temperatures, the semiclassical expression is dominated by single closed paths. As we lower the temperature

Basilio X. Santiago, Michael A. Strauss, Ofer Lahav, Marc Davis

We quantify the effects of Galactic extinction on the derived luminosity and diameter functions and on the density field of a redshift sample. Galaxy magnitudes are more affected by extinction than are diameters, although the effect on the latter is more variable from galaxy to galaxy, making it more difficult to quantify. We develop a maximum-likelihood app

Detlev Buchholz

A general method is presented which allows one to determine from the local gauge invariant observables of a quantum field theory the underlying particle and symmetry structures appearing at the lower (ultraviolet) end of the spatio--temporal scale. Particles which are confined to small scales, i.e., do not appear in the physical spectrum, can be uncovered in

Steffen Wilke, Matthias Scheffler

The potential energy surface (PES) of dissociative adsorption of H_2 on Pd(100) is investigated using density functional theory and the full-potential linear augmented plane wave (FP-LAPW) method. Several dissociation pathways are identified which have a vanishing energy barrier. A pronounced dependence of the potential energy on ``cartwheel&#39;&#39; rotati

Pedro T P Viana, Andrew R Liddle

We use the galaxy cluster X-ray temperature distribution function to constrain the amplitude of the power spectrum of density inhomogeneities on the scale corresponding to clusters. We carry out the analysis for critical density universes, for low density universes with a cosmological constant included to restore spatial flatness and for genuinely open unive

Stefan Mashkevich

We address the problem of finite-size anyons, i.e., composites of charges and finite radius magnetic flux tubes. Making perturbative calculations in this problem meets certain difficulties reminiscent of those in the problem of pointlike anyons. We show how to circumvent these difficulties for anyons of arbitrary spin. The case of spin 1/2 is special because

P. Saint-Gregoire, I. Luk&#39;yanchuk, E. Snoeck, C. Roucau

We present for the first time the evidence for a thermodynamically stable incommensurate elongated-triangle ($ELT$) phase in quartz observed by transmission electron microscopy at structural $α-β$ transition. The phase sequence on cooling is: uniform $β$ phase - stripe incommensurate phase (ferroelastic) - incommensurate equilateral-triangle ($EQT$) phase (f

M. Koseki, R. Kuriki

The massless Schwinger model without the kinetic term of gauge field has gauge anomaly. We quantize the model as an anomalous gauge theory in the most general class of gauge conditions. We show that the gauge field becomes a dynamical variable because of gauge anomaly.

Changhyun Ahn, Soonkeon Nam

We study the $SU(N)$, level $1$ Wess-Zumino-Witten model, with affine primary fields as spinon fields of fundamental representation. By evaluating the action of the Yangian generators $Q_{0}^{a}, Q_{1}^{a}$ and the Hamiltonian $H_2$ on two spinon states we get a new connection between this conformal field theory and the Calogero-Sutherland model with $SU(N)$

Cheongho Han

I demonstrate that one can detect pixel gravitational microlensing events at the rate $\sim 180\ {\rm events}\ {\rm yr}^{-1}$ and that some fraction of events ($\sim 15$) will be good enough to measure time scales at the $20\%$ level if the experiment is carried out toward the central M31 bulge region with a dedicated 1 m telescope and a $2{\rm K}\times2{\rm

Ezra Getzler

The symmetric group S_n acts freely on the configuration space of n distinct points in a quasi-projective variety. In this paper, we study the induced action of the symmetric group S_n on the de Rham cohomology of this space, using mixed Hodge theory, combined with methods from the theory of symmetric functions. (We prove a motivic version of this as well.)

V. Frolov, S. Hendy, A. L. Larsen

The interaction of a cosmic string with a four-dimensional stationary black hole is considered. If a part of an infinitely long string passes close to a black hole it can be captured. The final stationary configurations of such captured strings are investigated. A uniqueness theorem is proved, namely it is shown that the minimal 2-D surface $Σ$ describing a

N. P. Landsman

A formalism is developed for describing approximate classical behaviour in finite (but possibly large) quantum systems. This is done in terms of a structure common to classical and quantum mechanics, viz. a Poisson space with a transition probability. Both the limit where Planck&#39;s constant goes to zero in a fixed finite system and the limit where the siz

Nimai C. Mukhopadhyay, J. -F. Zhang, M. Benmerrouche

From the new Mainz data of eta photoproduction off protons\cite{ref1} and deuterons\cite{ref2}, we can extract, via the effective Lagrangian approach (ELA)\cite{ref3}, the electrostrong parameters $ξ_{p}$ and $ξ_{n}$ for the N$^*$(1535) excitation. These parameters are, in units of $10^{-4} MeV^{-1}$, $(2.20\pm 0.15)$ and $(-1.86\pm 0.20)$ respectively. They

Akira Ono, Hisashi Horiuchi

Statistical properties of the antisymmetrized molecular dynamics (AMD) are classical in the case of nucleon emission processes, while they are quantum mechanical for the processes without nucleon emission. We first clarify that there coexist mutually opposite two statistics in the AMD framework: One is the classical statistics of the motion of wave packet ce

G. -M. Rignanese, J. -M. Beuken, J. -P. Michenaud, X. Gonze

Parallel algorithms for ab initio calculations of vibrations modes of solids are presented and implemented under PVM. Load balancing and communication problems are dealt with in order to increase parallelism efficiency. For accurate time measurements, synchronisation of processes must be achieved. The results obtained by working with 1,2,4 and 8 processors o

Bernd Kohler, Steffen Wilke, Matthias Scheffler, Robert Kouba

Following the approach of Yu, Singh, and Krakauer [Phys. Rev. B 43 (1991) 6411] we extended the linearized augmented plane wave code WIEN of Blaha, Schwarz, and coworkers by the evaluation of forces. In this paper we describe the approach, demonstrate the high accuracy of the force calculation, and use them for an efficient geometry optimization of poly-atom

Shobhana Narasimhan, Matthias Scheffler

We investigate the thermal behavior of the (111) surface of silver, using phonon frequencies obtained from ab initio total energy calculations, and anharmonic effects treated within a quasiharmonic approximation. Our results reproduce the experimental observation of a large and anomalous increase in the surface thermal expansion at high temperatures [P. Stat

Narcisse Randrianantoanina

Let $X$ be a Banach space and $(Ω,Σ)$ be a measure space. We provide a characterization of sequences in the space of $X$-valued countably additive measures on $Ω,Σ)$ of bounded variation that generate complemented copies of $\ell_1$. As application, we prove that if a dual Banach space $E^*$ has Pełczyński&#39;s property (V*) then so does the space of $E^*$-

Reinhard Oehme

The analytic structure of {\it physical} amplitudes is considered for gauge theories with confinement of excitations corresponding to the elementary fields. Confinement is defined in terms of the BRST algebra. BRST-invariant, local, composite fields are introduced, which interpolate between physical asymptotic states. It is shown that the singularities of ph

Reinhard Oehme

The general theory of the reduction in the number of coupling parameters is discussed. The method involves renormalization group invariant relations between couplings. It is more general than the imposition of symmetries. There are reduced theories with no known symmetry. The reduction scheme is finding many applications. Discussed in some detail are the con

M. Golden, T. Han, G. Valencia

Phenomenology of a strongly-interacting electroweak symmetry breaking sector at current and future colliders is reviewed.

M. Svec

We present a new and improved model independent amplitude analysis of reactions $π^+ n_\uparrow \to π^+ π^- p$ at 5.98 and 11.85 GeV/c and $π^- p_\uparrow \to π^- π^+ n$ at 17.2 GeV/c measured with transversely polarized targets at the CERN Proton Synchrotron. A clear signal for $σ(750)$ resonance emerges in all four solutions for $S$-wave intensity $I_S$ at

Mikulas Gintner, Stephen Godfrey, Gilles Couture

We performed a detailed analysis of the process $e^+e^-\to \ell \nu q\bar{q}'$ where we included all tree level Feynman diagrams that contribute to this final state. We studied the sensitivity of this process to anomalous trilinear gauge boson couplings of the $WW\gamma$ and $WWZ$ vertices using two popular parametrizations. We used a maximum likelihood anal

F. Becattini, A. Giovannini, S. Lupia

Predictions of a thermodynamical model of hadron production for multiplicity distributions in $e^+e^-$ annihilations at LEP and PEP-PETRA centre of mass energies are shown. The production process is described as a two-step process in which primary hadrons emitted from the thermal source decay into final observable particles. The final charged tracks multipli

P. A. Henning, K. Nakamura, Y. Yamanaka

Conventional transport theory is not really applicable to non-equilibrium systems which exhibit strong quantum effects. We present two different approaches to overcome this problem. Firstly we point out how transport equations may be derived that incorporate a nontrivial spectral function as a typical quantum effect, and test this approach in a toy model of

Tomohiro Inagaki

We discuss the chiral symmetry restoration at high temperature and chemical potential for a four-fermion interaction theory in arbitrary dimensions ($2\leq D<4$). To investigate the ground state of the theory we calculate the effective potential and the gap equation using the method of the $1/N$ expansion. We study the phase structure at finite temperature a

M. Kawasaki, T. Moroi, T. Yanagida

We have reexamine the effect of entropy production on the cosmic axion density and find that the Peccei-Quinn scale $F_a$ larger than about $10^{15}$~GeV is not allowed even if large entropy is produced by the decays of coherent oscillations or non-relativistic massive particles. We stress that this result is independent of the details of models for the deca

F. M. Steffens, A. W. Thomas

We perform an analysis of the relation between the factorization scale and the masses of the quarks in the calculation of the hard gluon coefficient in polarized deep inelastic scattering. Particular attention is paid to the role of strange and charm quarks at finite momentum transfer. It is found that for the momentum transfer of the present experiments, th

Herbert Neuberger

This is an informal and approximate transcription of a talk presented at the DESY workshop, September 27--29, 1995. The basic message is that real and long overdue progress is taking place on the problem of regulating non--perturbatively chiral gauge theories. Several approaches are reviewed with emphasis on the overlap and some of the questions raised about

R. Adler, etal, J. Ellis, J. Lopez

We use fits to recent published CPLEAR data on neutral kaon decays to $π^+π^-$ and $πeν$ to constrain the CPT--violation parameters appearing in a formulation of the neutral kaon system as an open quantum-mechanical system. The obtained upper limits of the CPT--violation parameters are approaching the range suggested by certain ideas concerning quantum gravi

Eduard Prugovecki

The geometro-stochastic method of quantization provides a framework for quantum general relativity, in which the principal frame bundles of local Lorentz frames that underlie the fibre-theoretical approach to classical general relativity are replaced by Poincaré-covariant quantum frame bundles. In the semiclassical regime for quantum field theory in curved s

E. S. Cheb-Terrab, K. von Bulow

This work presents a brief discussion and a plan towards the analytical solving of Partial Differential Equations (PDEs) using symbolic computing, as well as an implementation of part of this plan as the PDEtools software-package of commands.

S. B. Huffman, J. E. Laird

This paper presents an approach to learning from situated, interactive tutorial instruction within an ongoing agent. Tutorial instruction is a flexible (and thus powerful) paradigm for teaching tasks because it allows an instructor to communicate whatever types of knowledge an agent might need in whatever situations might arise. To support this flexibility,

Yu-kui Zhou, Murray T. Batchelor

A general scheme has been proposed to study the critical behaviour of integrable interaction-round-a-face models with fixed boundary conditions. It has been shown that the boundary crossing symmetry plays an important role in determining the surface free energy. The surface specific heat exponent can thus be obtained without explicitly solving the reflection

Deniz Ertas, Mehran Kardar

The dynamical critical behavior of a single directed line driven in a random medium near the depinning threshold is studied both analytically (by renormalization group) and numerically, in the context of a Flux Line in a Type-II superconductor with a bulk current $\vec J$. In the absence of transverse fluctuations, the system reduces to recently studied mode

J. Lorenzana, G. A. Sawatzky

We calculate the effective charge for multimagnon infrared (IR) absorption assisted by phonons in a perovskite like antiferromagnet and we compute the spectra for two magnon absorption using interacting spin-wave theory. The full set of equations for the interacting two magnon problem is presented in the random phase approximation for arbitrary total momentu

Rosario Fazio, Dario Zappala`

We study the critical behavior of the conductivity $σ(ω)$ at the zero temperature superconductor-Mott insulator transition in $d$ space-time dimensions for a model of bosons with short-range interaction and no disorder. We obtain $σ(ω_n ) = (4e^2/\hbar) σ_ε ω_n^{1-ε}$, as predicted by the scaling theory, and the prefactor $σ_ε$ is calculated in the $ε$-expan

Jae Dong Noh, Doochul Kim

Finite-size corrections to the energy levels of the asymmetric six-vertex model transfer matrix are considered using the Bethe ansatz solution for the critical region. The non-universal complex anisotropy factor is related to the bulk susceptibilities. The universal Gaussian coupling constant $g$ is also related to the bulk susceptibilities as $g=2H^{-1/2}/π

H. C. Lee, P. B. Wiegmann

There exist strong experimental evidences for the dimensional cross-over from two to three dimensions as \lan compounds are overdoped. In this paper we describe the dimensional cross-over of the layered correlated metal in the gauge theory framework. In particular, we obtain the anomalous exponent 3/2 for the temperature dependence of resistivity observed in

Leo Radzihovsky, John Toner

We show that fluctuating tethered membranes with {\it any} intrinsic anisotropy unavoidably exhibit a new phase between the previously predicted ``flat&#39;&#39; and ``crumpled&#39;&#39; phases, in high spatial dimensions $d$ where the crumpled phase exists. In this new &#34;tubule&#34; phase, the membrane is crumpled in one direction but extended nearly str

Yasuhiro Hatsugai, Mahito Kohmoto, Yong-Shi Wu

Integral quantum Hall plateau transitions in a planar lattice system due to gap collapse can be described by an effective field theory with Dirac fermions. We discuss how to reproduce the correct integral values for the Hall conductance, $σ_{xy}$, before and after the plateau transition, which are dictated by the microscopic topological invariant. In additio

J. Chiang, N. Murray

Using the disk wind model of Murray et al. (1995), we calculate line profiles and frequency-resolved response functions for broad line emission from the surface of an accretion disk in an AGN in the presence of a radiatively driven wind. We find that the combined effects of the shears in the wind and in the disk itself produce anisotropic line emission which

Isaac Shlosman, Peter Vitello, Christopher W. Mauche

We study the eclipsing nova-like variable V347 Pup by matching its UV emission line profiles in and out of eclipse to synthetic lines using a 3D kinematic and radiation transfer model. Our results support the accretion disk origin of winds in non-magnetic CVs as opposite to the WD origin. Our main point concerns the importance of rotation for the UV emission

José M. Solanes, Riccardo Giovanelli, Martha P. Haynes

A standard parametric maximum-likelihood technique is used to determine both the probability distribution over total HI mass $M_{\rm HI}$ and the regression of this quantity on the linear optical diameter $D_{\rm o}$ for field giant spirals (Sa-Sc) from a complete HI-flux-limited data set of these objects. Gaussian and Schechter parametrizations of the HI ma

Volker Mueller

High resolution $N$-body simulations for variants of the CDM model are used to derive the redshift dependence of galaxy formation and of galaxy correlation functions. The reconstructed power spectra and clustering properties provide a sensible test for the underlying power spectra. We compare our simulations with new results of the analysis of recent redshif

Matthias Steinmetz

New simulations are presented which investigate the formation of smaller groups of galaxies in a CDM like universe. The simulations follow the evolution of dark matter and gas and are performed with an SPH code adapted for the special-purpose hardware GRAPE. The mass resolution in the baryonic component is 5 10^6 Msol, the spatial resolution is 1.5 kpc. A su

Sally D. Hunsberger, Jane C. Charlton, Dennis Zaritsky

From R-band images of 42 Hickson compact groups, we present a sample of 47 candidate dwarf galaxies that are associated with the tidal tails and arms in the groups. The candidates, found in 15 tidal features, have R magnitudes and masses (for M/L = 1) in the ranges -16.5 < M_R - 5 log h_{75} < -11.5 and 2x10^6 M_{\odot} < M < 2x10^8 M_{\odot}, respectively.

S. Hosono, B. H. Lian, S. -T. Yau

We present a detailed study of the generalized hypergeometric system introduced by Gel&#39;fand, Kapranov and Zelevinski (GKZ-hypergeometric system) in the context of toric geometry. GKZ systems arise naturally in the moduli theory of Calabi-Yau toric varieties, and play an important role in applications of the mirror symmetry. We find that the Gröbner basis