July 1994 arXiv papers — page 2

Franz E. Schunck, Eckehard W. Mielke

The mechanism of the initial inflation of the universe is based on gravitationally coupled scalar fields $ϕ$. Various scenarios are distinguished by the choice of an {\it effective self--interaction potential} $U(ϕ)$ which simulates a {\it temporarily} non--vanishing {\em cosmological term}. Using the Hubble expansion parameter $H$ as a new ``time" coord

J. J. Halliwell

I review the decoherent (or consistent) histories approach to quantum mechanics, due to Griffiths, to Gell-Mann and Hartle, and to Omnes. This is an approach to standard quantum theory specifically designed to apply to genuinely closed systems, up to and including the entire universe. It does not depend on an assumed separation of classical and quantum domai

S. Flach, K. Kladko, C. R. Willis

We analyze the origin and features of localized excitations in a discrete two-dimensional Hamiltonian lattice. The lattice obeys discrete translational symmetry, and the localized excitations exist because of the presence of nonlinearities. We connect the presence of these excitations with the existence of local integrability of the original N degree of free

S. Flach, C. R. Willis

We analyze typical models which intend to describe (parts of) the dynamics of H-Bonds in DNA. We show that these models generically allow for nonlinear localized excitatons (NLEs) (discrete breathers). We especially study the scattering of phonons by NLEs and observe strong reflection of phonons by the NLE. We relate our results to the problem of functioning

Helen Au-Yang, Jacques H. H. Perk

In honor of Onsager's ninetieth birthday, we like to review some exact results obtained so far in the chiral Potts models and to translate these results into language more transparent to physicists, so that experts in Monte Carlo calculations, high and low temperature expansions, and various other methods, can use them. We shall pay special attention to

Gabriele Migliorini, Felix Ritort

We have investigated the nature of the dynamical behaviour in low autocorrelation binary sequences. These models do have a glass transition $T_G$ of a purely dynamical nature. Above the glass transition the dynamics is not fully ergodic and relaxation times diverge like a power law $τ\sim (T-T_G)^{-γ}$ with $γ$ close to $2$. Approaching the glass transition

Dekang Lin

We present an efficient, broad-coverage, principle-based parser for English. The parser has been implemented in C++ and runs on SUN Sparcstations with X-windows. It contains a lexicon with over 90,000 entries, constructed automatically by applying a set of extraction and conversion rules to entries from machine readable dictionaries.

L. A. Ford, D. L. Band, J. L. Matteson, M. S. Briggs

We investigate spectral evolution in 37 bright, long gamma-ray bursts observed with the BATSE Spectroscopy Detectors. High resolution spectra are characterized by the energy of the peak of \nfn~and the evolution of this quantity is examined relative to the emission intensity. In most cases it is found that this peak energy either rises with or slightly prece

Juan Garcia-Bellido

A theory of evolution for the Universe requires both a mutation mechanism and a selection mechanism. We propose that both can be encountered in the stochastic approach to quantum cosmology. In Brans--Dicke chaotic inflation, the quantum fluctuations of Planck mass behave as mutations, such that new inflationary domains may contain values of Planck mass that

A. Dobado, J. R. Pelaez, M. Urdiales

We have explicitely calculated the tree level elastic scattering cross sections of two longitudinal gauge bosons, up to four derivatives in the chiral expansion both with and without using the Equivalence Theorem (ET). The numerical results show the existence of new and severe restrictions in the ET energy applicability range, as it was stated in our recent

Piljin Yi

Pair-production of magnetic Reissner-Nordström black holes (of charges $\pm q$) was recently studied in the leading WKB approximation. Here, we consider generic quantum fluctuations in the corresponding instanton geometry given by the Euclidean Ernst metric, in order to simulate the behaviour of the one-loop tunneling rate. A detailed study of the Ernst metr

Fernando Torres

A curve $X$ is said to be of type $(N,\gamma)$ if it is an $N$--sheeted covering of a curve of genus $\gamma$ with at least one totally ramified point. A numerical semigroup $H$ is said to be of type $(N,\gamma)$ if it has $\gamma$ positive multiples of $N$ in $[N,2N\gamma]$ such that its $\gamma^{th}$ element is $2N\gamma $ and $(2\gamma+1)N \in H$. If the

Charles B. Thorn

We explore the application of approximation schemes from many body physics, including the Hartree-Fock method and random phase approximation (RPA), to the problem of analyzing the low energy excitations of a polymer chain made up of bosonic string bits. We accordingly obtain an expression for the rest tension $T_0$ of the bosonic relativistic string in terms

N. A. Ansari, L. Di Fiore, M. A. Man'ko, V. I. Man'ko

It is shown that the even and odd coherent light and other nonclassical states of light like superposition of coherent states with different phases may replace the squeezed light in interferometric gravitational wave detector to increase its sensitivity. (Contribution to the Second Workshop on Harmonic Oscillator, Cocoyoc, Mexico, March 1994)

S. M. Bilenky, C. Giunti

The results of a solar model independent analysis of the existing solar neutrino data under the assumption of MSW transitions in matter or vacuum oscillations (in the cases of $ν_{e}$--$ν_μ(ν_τ)$ and $ν_{e}$--$ν_{\mathrm{S}}$ mixing) are presented. The analysis was done in two cases. In the first case no assumptions on the value of the total fluxes of neutri

V. P. Gusynin, V. A. Miransky, I. A. Shovkovy

It is shown that in $2+1$ dimensions, a constant magnetic field is a strong catalyst of dynamical flavor symmetry breaking, leading to generating a fermion dynamical mass even at the weakest attractive interaction between fermions. The essence of this effect is that in a magnetic field, in $2+1$ dimensions, the dynamics of fermion pairing is essentially one-

C. Anastopoulos, J. J. Halliwell

We study the time evolution of the reduced Wigner function for a class of quantum Brownian motion models. We derive two generalized uncertainty relations. The first consists of a sharp lower bound on the uncertainty function, $U = (Δp)^2 (Δq)^2 $, after evolution for time $t$ in the presence of an environment. The second, a stronger and simpler result, consi

A. Cappi, S. Maurogordato

We analyse the two--dimensional all--sky distribution of rich Abell and ACO galaxy clusters by using counts in cells and measuring the high--order area--averaged angular correlation functions. Confirming previous results, we find a well defined hierarchical relation between the two and three--point correlation functions, remarkably constant with scale. In th

R. Triay, M. Lachieze-Rey, S. Rauzy

We provide the mathematical framework which elucidates the way of using a Tully-Fisher (TF) like relation in the determination of the Hubble constant $H_0$, as well as for distances of galaxies. The methods related to the so-called Direct and Inverse TF Relations (herein DTF and ITF) are interpreted as maximum likelihood statistics. We show that, as long as

Robert Rudd

We study the free energy of the pure glue QCD string with a torus target space and the gauge groups $SU(N)$ and (chiral) $U(N)$. It is highly constrained by a strong/weak gauge coupling duality which results in modular covariance. The string free energy is computed exactly in terms of modular forms for worldsheet genera 1 - 8. It has a surprisingly mild sing

F. A. Lunev

It is presented the general method that allows to formulate 4D $SU(N)$ Yang - Mills theory in terms of only local gauge invariant variables. For the case N=2, that is discussed in details, this gauge invariant formulation appears to be very similar to $ R^2 $-gravity.

F. A. Lunev

It is shown that every Feynman integral can be interpreted as Green function of some linear differential operator with constant coefficients. This definition is equivalent to usual one but needs no regularization and application of $R$-operation. It is argued that presented formalism is convenient for practical calculations of Feynman integrals.

V. V. Dodonov, Ya. A. Korennoy, V. I. Man'ko, Y. A. Muukhin

Photon distribution function, means and dispersions are found explicitly for the nonclassical state of light which is created from the photon--added coherent state $\vert α,m \rangle$ due to a time--dependence of the frequency of the electromagnetic field oscillator. Generating function for factorial momenta is obtained. The Wigner function and Q--function a

J. M. Aroca, M. Baig, H. Fort

It is showed how the Hamiltonian lattice $loop$ $representation$ can be cast straightforwardly in the Lagrangian formalism. The procedure is general and here we present the simplest case: pure compact QED. This connection has been shaded by the non canonical character of the algebra of the fundamental loop operators. The loops represent tubes of electric flu

C. H. Oh, K. Singh

We examine some of the implications of implementing the usual boundary conditions on the closed bosonic string in the hamiltonian framework. Using the KN formalism, it is shown that at the quantum level, the resulting constraints lead to relations among the periods of the basis 1-forms. These are compared with those of Riemanns' which arise from a differ

Vidyut Jain

We show that, for standard N=1 supergravity coupled to chiral matter, if the Kahler potential has no terms linear in chiral superfields then none are generated through quad. div. one--loop corrections. If however <V>=0 and susy is spontaneously broken, linear terms are present and new linear terms may be generated due to nonrenormalizable couplings in K. The

M. V. Libanov, V. A. Rubakov, D. T. Son, S. V. Troitsky

It is argued that the amplitudes of the production of $n$ soft scalar particles by one or a few energetic ones in theories like $λϕ^4$ has the exponential form, $A_n\propto\sqrt{n!}\exp[{1\overλ}F(λn,ε)]$, in the regime $λ\to 0$, $λn={fixed}$, $ε={fixed}$, where $ε$ is the typical kinetic energy of outgoing particles. Existing results support this conjecture

J. Hüfner, S. P. Klevansky, E. Quack, P. Zhuang

Hadronization at finite temperature $T$ is discussed in the framework of the Nambu--Jona-Lasinio model. The differential cross-section for the conversion of a quark--antiquark pair into two pions to first order in a $1/N_c$ expansion is calculated as a function of the c.m.~energy $s$ and temperature $T$. In particular, approaching the temperature $T_c$ of th

Gustavo Burdman

The Standard Model predictions for $D^0$-$\bar{D}^0$ mixing and CP violation in $D$ decays are revised. The emphasis is put on obtaining the order of magnitude of the effects. In the case of mixing, the different approaches to the long distance contributions are carefully discussed. The size of CP asymmetries is discussed in general and some specific calcula

Hans-Thomas Elze

Or: ``How to generate an ensemble in a single event?&#39;&#39; Following recent work on entropy in strong interactions, I explain the concept of environment-induced quantum decoherence in elementary quantum mechanics. The classically chaotic inverted oscillator becomes partially decoherent already in the environment of a single other oscillator performing on

A. P Martynenko, V. A. Saleev

We present the results of a calculation of the intrinsic charm quark contribution to $J/ψ$ plus open charm associated production at large transverse momentum in hadron collisions at high energies. It is shown that the value of the cross section for such process and its energy dependence are significantly determined by the choice of charm quark distribution f

V. V. Kiselev

Using a specific scheme of the QCD sum rules, one derives the relation for leptonic constants of $nS$-wave heavy qiarkonia, so $f^2_{n_1}/f^2_{n_2}= n_2/n_1$, that does not depend on the quarkonium content, and it is in a good agreement with the experimental values of constants for the $ψ$- and $Υ$-families.

C. Bourrely, J. Soffer

The Pauli exclusion principle is advocated for constructing the proton and neutron deep inelastic structure functions in terms of Fermi-Dirac distributions that we parametrize with very few parameters. It allows a fair description of the recent NMC data on $F^p_2(x,Q^2)$ and $F^n_2(x,Q^2)$ at $Q^2=4 GeV^2$, as well as the CCFR neutrino data at $Q^2=3$ and $5

V. V. Kiselev

Using a specific scheme of the QCD sum rules, one derives an universal formula for the mass differences for the $nS$-levels of heavy qiarkonium. This relation does not depend on the flavours of the heavy quarks, composing the quarkonium, and it is in a good agreement with the experimental mass values for the $ψ$- and $Υ$-families.

A. Capella, A. Kaidalov, C. Merino, J. Tran Thanh Van

The diffraction dissociation of virtual photons is considered in the framework of conventional Regge theory. It is shown that the recent HERA data on large rapidity gap events can be successfully described in terms of the Pomeron structure function. Using Regge factorization, the latter can be related to the deuteron structure function. The parameters which

V. V. Kiselev

In the framework of a specific scheme of the QCD sum rules for $S$-wave levels of the heavy quarkonium, one derives an expression, relating the energetic density of quarkonium states and universal characteristics in the heavy quarkonium physics, such as the difference between the masses of a heavy quark $Q$ and meson $(Q\bar q)$ and the number of heavy quark

J. Ohnemus

The process $p p \to Z γ+ X \to \ell^- \ell^+ γ+ X$, where $\ell$ denotes a lepton, is calculated to order $α_s$. Total and differential cross sections, with acceptance cuts imposed on the leptons and photon, are given for the Tevatron and LHC center of mass energies. In general, invariant mass and angular distributions are simply scaled up in magnitude by t

Wolfgang Beirl, Harald Markum, J&#34;urgen Riedler

We investigate quantum gravity in four dimensions using the Regge approach on triangulations of the four-torus with general, non-regular incidence matrices. We find that the simplicial lattice tends to develop spikes for vertices with low coordination numbers even for vanishing gravitational coupling. Different to the regular, hypercubic lattices almost excl

M. Billo&#39;, M. Caselle, A. D&#39;Adda, L. Magnea

We study analytically the phase diagram of the pure $SU(N)$ lattice gauge theory at finite temperature, and we attempt to estimate the critical deconfinement temperature. We apply large $N$ techniques to the Wilson and to the Heat Kernel action, and we study the resulting models both in the strong coupling and in the weak coupling limits. Using the Heat Kern

A. Higuchi, R. M. Wald

We apply a recent proposal for defining states and observables in quantum gravity to simple models. First, we consider a Klein-Gordon particle in an ex- ternal potential in Minkowski space and compare our proposal to the theory ob- tained by deparametrizing with respect to a time slicing prior to quantiza- tion. We show explicitly that the dynamics of the de

M. Fabrizio, Alexander O. Gogolin

We show that the spin dynamics of the 4--channel Kondo model is equivalent to the one of a model with a spin 1/2 impurity coupled to spin 1 conduction electrons. By abelian bosonization of the latter model we find a kind of Toulouse limit analogous to that recently discussed by Emery and Kivelson for the 2--channel case. We analyse the model by exploiting th

Alexander O. Gogolin

Lecture given at the Landau Institute Seminar, Col de Port, March 1994, intended for a qualitative discussion of recent theoretical results in the physics of 1D quantum wires. The consideration is mainly focused on observable quantities, such as conductance, persistent current, and X-Ray response functions, which are discussed in simple terms.

George Kiraz

This paper presents an implemented multi-tape two-level model capable of describing Semitic non-linear morphology. The computational framework behind the current work is motivated by Kay (1987); the formalism presented here is an extension to the formalism reported by Pulman and Hepple (1993). The objectives of the current work are: to stay as close as possi

Pim van der Eijk

A quantitative representation of discourse structure can be computed by measuring lexical cohesion relations among adjacent blocks of text. These representations have been proposed to deal with sub-topic text segmentation. In a parallel corpus, similar representations can be derived for versions of a text in various languages. These can be used for parallel

R. Lima, M. Rahibe

In this work, we give a rigorous explicit formula for the Lyapunov exponent for some binary infinite products of random $2\times 2$ real matrices. All these products are constructed using only two types of matrices, $A$ and $B$, which are chosen according to a stochastic process. The matrix $A$ is singular, namely its determinant is zero. This formula is der

J. A. Dente, R. Vilela Mendes, R. Lima

We investigate the ability of a local bi-orthogonal decomposition to build texture segmentation of images. Using the structures associated to the local decomposition of the image independent row and columns we perform a segmentation, where the regions are defined by the property of having a smooth variation of the corresponding entropy. Examples are choosen

M. Bellazzini, A. Pasquali, L. Federici, F. R. Ferraro

Galactic Globular Clusters (GCs) containing bright X sources (L_x > 10^{36} erg/s), commonly associated with Low Mass X-Ray Binaries (LMXBs), are found to be significantly denser and more metal-rich than normal non-X-ray clusters both in the Galaxy and in M31. Within a framework where LMXBs in GCs are generated via tidal captures in high-density clusters and

Chung-Pei Ma, Edmund Bertschinger

The abundance of galactic systems at high redshifts can impose a strong constraint on the cold+hot dark matter (CDM+HDM) models. The hot component reduces the excessive small-scale power in the COBE-normalized CDM model but also delays the epoch of galaxy formation. We present results from the first numerical simulations that have enough dynamic range to add

A. Udalski, M. Szymanski, S. Mao, R. Di Stefano

We present the light curve of an unusual variable object, OGLE #7, detected during the OGLE search for microlensing events. After one season of being in a low, normal state, the star brightened by more than 2~mag with a characteristic double-maximum shape, and returned to normal brightness after 60 days. We consider possible explanations of the photometric b

Masatoshi Usami, Tomoyuki Hanawa, Mitsuaki Fujimoto

We study the gravitational instability of an isothermal gaseous slab formed by cloud-cloud collision and compression at the cloud interface. The compressed gaseous slab rotates and has velocity shear except when the collision is not exactly head-on. The effects of the rotation and velocity shear on the gravitational instability have been evaluated for the fi

C. D. Bailyn, E. P. Rubenstein, T. M. Girard, D. Dinescu

We have searched deep optical images of the globular cluster M4 for a possible optical counterpart for the third body in the PSR B1620-26 system. We identify as a possible optical counterpart a star located within $0.3&#39;&#39;$ of the nominal pulsar position with $V\approx 20$. This magnitude is consistent with a main sequence cluster member with $M\approx

Igor R. Klebanov

Large $N$ matrix models modified by terms of the form $ g(\TrΦ^n)^2$ generate random surfaces which touch at isolated points. Matrix model results indicate that, as $g$ is increased to a special value $g_t$, the string susceptibility exponent suddenly jumps from its conventional value $γ$ to ${γ\overγ-1}$. We study this effect in Ł gravity and attribute it t

D. Johnston, J-P. Kownacki, A. Krzywicki

A method of ``blocking&#39;&#39; triangulations that rests on the self-similarity feature of dynamically triangulated random manifolds is proposed. The method is used to define the renormalization group for random geometries. As an illustration, the idea is applied to pure euclidean quantum gravity in two dimensions. Generalisation to more complicated system

Marco Vekic, Shao Liu, Herbert W. Hamber

A model describing Ising spins with short range interactions moving randomly in a plane is considered. In the presence of a hard core repulsion, which prevents the Ising spins from overlapping, the model is analogous to a dynamically triangulated Ising model with spins constrained to move on a flat surface. As a function of coupling strength and hard core re

G. J. Chaitin

We summarize four different versions of our course notes on the limits of mathematics.

M. Baig, H. Fort, JB Kogut, S. Kim

The phase diagram and critical behavior of scalar quantum electrodynamics are investigated using lattice gauge theory techniques. The lattice action fixes the length of the scalar (``Higgs'') field and treats the gauge field as non-compact. The phase diagram is two dimensional. No fine tuning or extrapolations are needed to study the theory's critical behovi

L. L. Jenkovszky, B. V. Struminsky

Recent data on single diffraction dissociation, measured by the CDF at the Tevatron show a moderate increase with energy of the cross section, thus confirming the predictions based on the dipole pomeron model.

Jun Nishimura, Masaki Oshikawa

We study the fractal structure of the surface in two-dimensional quantum Regge calculus by performing Monte Carlo simulation with up to 200,000 triangles. The result can be compared with the universal scaling function obtained analytically in the continuum limit of dynamical triangulation, which provides us with a definite criterion whether Regge calculus se

Shuxue Ding

We show that the cosmological sphaleron of Einstein-Yang-Mills system can be produced from real tunneling geometries. The sphaleron will tend to roll down to the vacuum or pure gauge field configuration, when the universe evolves in the Lorentzian signature region with the sphaleron and the corresponding hypersurface being the initial data for the Yang-Mills

Derek B. Leinweber

Effective quark magnetic moments are extracted from experimental measurements as a function of the strangeness magnetic moment of the nucleon. Assumptions made in even the most general quark model analyses are ruled out by this investigation. Ab initio QCD calculations demand a non-trivial role for strange quarks in the nucleon. The effective moments from QC

C. H. M. van Antwerpen, I. R. Afnan

The Ward-Takahashi identities are central to the gauge invariance of the photoproduction amplitude. Here we demonstrate that unitarity and in particular the inclusion of both the $πN$ and $γπN$ thresholds on equal footing yields a photoproduction amplitude that satisfies both two-body unitarity and the generalized Ward-Takahashi identities. The final amplitu

Erik Koelink

Generalised matrix elements of the irreducible representations of the quantum $SU(2)$ group are defined using certain orthonormal bases of the representation space. The generalised matrix elements are relatively infinitesimal invariant with respect to Lie algebra like elements of the quantised universal enveloping algebra of $sl(2)$. A full proof of the theo

S. De Martino, S. De Siena, F. Illuminati

In the framework of Nelson stochastic quantization we derive exact non-stationary states for a class of time-dependent potentials. The wave-packets follow a classical motion with constant dispersion. The new states thus define a possible extension of the harmonic-oscillator coherent states to more general potentials. As an explicit example we give a detailed

R. Brustein, M. Faux, B. Ovrut

We show that the continuum limit of one-dimensional N=2 supersymmetric matrix models can be described by a two-dimensional interacting field theory of a massless boson and two chiral fermions. We interpret this field theory as a two-dimensional N=1 supersymmetric theory of two chiral superfields, in which one of the chiral superfields has a non-trivial vacuu

W. A. Sabra, O. A. Soloviev, S. Thomas

We discuss some implications of the gravitational dressing of the renormalization group for conformal field theories perturbed by relevant operators. The renormalization group flows are defined with respect to the dilatation operator associated with the $J_0^{(0)}$ mode of the $SL(2,R)$ affine algebra. We discuss the possibility of passing under the $c=25$ b

R. Bonisch

The minimal Standard Model exhibits a nontrivial chiral U(2) symmetry if the vev and the hypercharge splitting (Delta) of right-handed leptons (quarks) in a family vanish and Q=T_0 + Y independently in each helicity sector. As a generalization, we start with SU(2)_L x SU(2)_R x U(1)_{(B-L)} and introduce Delta as a continuous parameter which is a measure of

Marialuisa Frau, Alberto Lerda, Stefano Sciuto

We discuss the connection between anyons (particles with fractional statistics) and deformed Lie algebras (quantum groups). After a brief review of the main properties of anyons, we present the details of the anyonic realization of all deformed classical Lie algebras in terms of anyonic oscillators. The deformation parameter of the quantum groups is directly

Keiji Kikkawa, Humitaka Tamura

Some part of the local gauge symmetries in the low energy region, say, lower than GUT or the Planck energy can be an induced symmetry describable with the holonomy fields associated with a topologically non-trivial structure of partially compactified space. In the case where a six dimensional space is compactified by the Kaluza-Klein mechanism into a product

A. Y. Shiekh

A suggestion is made for quantizing gravity perturbatively, and is illustrated for the example of a massive scalar field with gravity.

Marcelo Gleiser

In this talk I briefly review the main ideas and challenges involved in the computation of the baryon asymmetry of the Universe. (Invited talk given at ``The Birth of the Universe and Fundamental Physics&#39;&#39;, Rome, May 18--21, 1994.)

Sean Gavin

Measurements of disoriented chiral condensates in heavy ion collisions at RHIC and the LHC can yield fundamental information on the nature of the QCD phase transition. I review theoretical efforts to understand the evolution of the condensate and present new results on experimental signals in the single pion spectrum and in pion interferometry. (Invited talk

Thomas G. Rizzo

While the much discussed lepton-number violating process $e^-e^-\rightarrow W_R^-W_R^-$ provides an excellent probe of both the Majorana nature of the right-handed neutrino and the symmetry breaking sector of the Left-Right Symmetric Model, it is likely that $W_R$&#39;s are too massive to be pair produced at the NLC with $\sqrt {s}$ in the 1-1.5 TeV range. W

Thomas G. Rizzo

The Tevatron and the Next Linear Collider(NLC) will be excellent tools for probing the detailed nature of the top quark. We perform a preliminary examination of the influence of an anomalous chromomagnetic moment for the top, $κ$, on the characteristics of $t\bar t$ production at the Tevatron and on the spectrum of gluon radiation associated with $t\bar t$ p

V. A. Litvin, S. R. Slabospitsky, A. V. Shvorob

The hypothetic R--resonance production (anomalous &#34;$l\bar lγγ$&#34; events at LEP) with 60 GeV mass at FNAL hadron collider has been considered. The cross-section of this R-resonance production with the consequent decay $R \to γγ$ is obtained. Various distributions of leptons and photons in the process $p\bar p \to l\bar l R (\to γγ) X$ are calculated.

V. A. Litvin, S. R. Slabospitsky

The $e^{+}\,e^{-}\,\rightarrow\,l^{+}\, ł^{-}\,γ\,γ$ anomalous events, detected by $L3$ de\-tec\-tor at $e^+ e^-$ $CERN-LEP$ collider have been analysed. It has been shown that the interpretation of such events as a manifestation of scalar (pseudoscalar) resonance with the mass of 60 GeV contradicts other experimental data. In case of a possible existence th

S. Aoki, M. Fukugita, S. Hashimoto, N. Ishizuka

We demonstrate that sea quark effects of a magnitude expected from renormalization group considerations are clearly visible in the strong coupling constant measured in current full QCD simulations. Building on this result an estimate of $α_{\overline{MS}}^{(5)}(M_Z)$ is made employing the charmonium $1S-1P$ mass splitting calculated on full QCD configuration

A. Lukas

In this paper wormhole effects on $SO(3)$ YM theory are examined. The wormhole wave functions for the scalar, the vector and the tensor expansion modes are computed assuming a small gauge coupling which leads to an effective decoupling of gravity and YM theory. These results are used to determine the wormhole vertices and the corresponding effective operator

Michael K. Murray

Just as $\Cstar$ principal bundles provide a geometric realisation of two-dimensional integral cohomology; gerbes or sheaves of groupoids, provide a geometric realisation of three dimensional integral cohomology through their Dixmier-Douady class. I consider an alternative, related, geometric realisation of three dimensional cohomology called a bundle gerbe.

A. V. Balatsky, M. I. Salkola, A. Rosengren

It is shown that a single, strongly scattering impurity produces a bound or a virtual bound quasiparticle state inside the gap in a $d$-wave superconductor. The explicit form of the bound state wave function is found to decay exponentially with angle-dependent range. These states provide a natural explanation of the second Cu NMR rate arising from the sites

J. K. Freericks, Mark Jarrell

The competition between commensurate and incommensurate spin-density-wave phases in the infinite-dimensional single-band Hubbard model is examined with quantum Monte Carlo simulation and strong and weak coupling approximations. Quantum fluctuations modify the weak-coupling phase diagram by factors of order unity and produce remarkable agreement with the quan

S. De Martino, S. De Siena, F. Illuminati, G. Vitiello

It is shown that stochastic processes of diffusion type possess, in all generality, a structure of uncertainty relations and of coherent and squeezed states. This fact is used to obtain, via Nelson stochastic formulation of quantum mechanics, the harmonic-oscillator coherent and squeezed states. The method allows to derive new minimum uncertainty states in t

Jan Brinckmann

A new perturbational approach to spectral and thermal properties of strongly correlated electron systems is presented: The Anderson model is reexamined for $U\to\infty$\,, and it is shown that an expansion of Green&#39;s functions with respect to the hybridization $V$ built on Feynman diagrams obeying standard rules is possible. The local correlations of the

Anders Smith, Rafael Taboryski, Luise Theil Hansen, Claus B. Sorensen

We report magnetoresistance measurements on a two-dimensional electron gas (2DEG) made from a high mobility GaAs/AlGaAs heterostructure, where the externally applied magnetic field was expelled from regions of the semiconductor by means of superconducting lead grains randomly distributed on the surface of the sample. A theoretical explanation in excellent ag

R. Eder, Y. Ohta

We present an exact diagonalization study of the electron momentum distribution n(k) in small clusters of t-J model for different hole concentrations and t/J. Structures in n(k) which were previously interpreted as a `large&#39; Fermi surface are identified as originating from the well known many-body backflow. To obtain reliable information about the true F

Pascale Fung, Kenneth Church

Various methods have been proposed for aligning texts in two or more languages such as the Canadian Parliamentary Debates(Hansards). Some of these methods generate a bilingual lexicon as a by-product. We present an alternative alignment strategy which we call K-vec, that starts by estimating the lexicon. For example, it discovers that the English word &#34;f

Ronnie Mainieri, Robert Ecke

We obtain a five-step approximation to the quasiperiodic dynamic scaling function for experimental Rayleigh-Be&#39;nard convection data. When errors are taken into account in the experiment, the f(alpha) spectrum of scalings is equivalent to just two of these five scales. To overcome this limitation, we develop a robust technique for extracting the scaling f

E. Gaztanaga, J. Frieman

On large scales, the higher order moments of the mass distribution, $S_J=\xibar_J/\xibar_2^{J-1}$, e.g., the skewness $S_3$ and kurtosis $S_4$, can be predicted using non-linear perturbation theory. Comparison of these predictions with moments of the observed galaxy distribution probes the bias between galaxies and mass. Applying this method to models with i

A. C. Edge, H. Boehringer, L. Guzzo

We report the serendipitous discovery of a giant grvitational arc in the Abell Supplementary cluster S295 during optical follow-up observations of clusters detected in the ROSAT All-Sky Survey. The cluster has a redshift z=0.3007 and a velocity dispersion of about 900 km/sec. This is the first giant arc newly found in a ROSAT Survey cluster, indicating the p

V. Mohan, D. K. Ojha, O. Bienayme, D. C. Paliwal

We have been doing a photometric and astrometric sample survey programme on Schmidt plates in a few selected directions in the Galaxy with an aim to study galactic stellar populations. In order to calibrate Schmidt plates photometrically, it is necessary to have a number of photometric standards which cover the entire range of magnitudes to be studied on the

G. B. Dalton, R. A. C. Croft, G. Efstathiou, W. J. Sutherland

We present new estimates of the spatial two-point correlation function of rich clusters of galaxies selected from the APM Galaxy Survey. We have measured redshifts for a sample of $364$ clusters out to a depth of $\sim 450\hmpc$. The clusters have a mean space density of $\bar{n} = 3.4\times 10^{-5}\hmpccc$. The two-point correlation function, $ξ_{cc}$, for

D. K. Ojha, O. Bienayme, A. C. Robin, V. Mohan

We have derived a new photographic photometry and proper motions for 20000 stars with completeness to V = 18 in the direction of galactic center at the intermediate latitude (l = 3 deg,b = 47 deg; alpha(1950)=15h 18m, delta(1950) = +02deg 16&#39;) for a 15.5 sq deg field. The combination of four glass copies of the Palomar Observatory Sky Survey (i.e. POSS 1

Yoshiaki Sofue, Ken-ichi Wakamatsu, David F. Malin

We study the morphology of dark lanes and filaments in the dust-rich galaxy NGC 253 using an unsharp-masked $B$-band optical photograph. Dust features are classified as `arcs&#39;, which have heights and scale radius of about 100 to 300 pc, connecting two or more dark clouds, and `loops&#39; and `bubbles&#39;, which are developed forms of arcs, expanding int

A. Jadczyk

The law of track formation in cloud chambers is derived from the Liouville equation with a simple Lindblad&#39;s type generator that describes coupling between a quantum particle and a classical, continuous, medium of two--state detectors. Piecewise deterministic random process (PDP) corresponding to the Liouville equation is derived. The process consists of

David D. Lewis, William A. Gale

The ability to cheaply train text classifiers is critical to their use in information retrieval, content analysis, natural language processing, and other tasks involving data which is partly or fully textual. An algorithm for sequential sampling during machine learning of statistical classifiers was developed and tested on a newswire text categorization task

Douglas Scott, Martin White

Fluctuations in the CMB have now been detected over a wide range of angular scales, and a consistent picture seems to be emerging. The data cannot currently constrain a large number of cosmological parameters, but it is clear that there is more information than just the normalization of the models. Here we use the data to constrain a second parameter, namely

Arnon Dar

The most simple observed cases of gravitational lensing of distant quasars and galaxies by galaxies and clusters of galaxies are used to test Einstein&#39;s theory of General Relativity and Newtonian Gravity over galactic and intergalactic distances. They extend the distance range over which Newton-Einstein Gravity has been tested by 10 orders of magnitude.

R. Brada, M. Milgrom

We Consider models of thin disks (with and without bulges) in the Bekenstein-Milgrom formulation of MOND as a modification of Newtonian gravity. Analytic solutions are found for the full gravitational fields of Kuzmin disks, and of disk-plus-bulge generalizations of them. For all these models a simple algebraic relation between the MOND potential field and t

D. V. Gal&#39;tsov, O. V. Kechkin

The ten--parametric internal symmetry group is found in the $D=4$ Einstein--Maxwell--Dilaton--Axion theory restricted to space--times admitting a Killing vector field. The group includes dilaton--axion $SL(2,R)$ duality and Harrison--type transformations which are similar to some target--space duality boosts, but act on a different set of variables. New symm

Giovanni Felder

An elliptic version of quantum groups is proposed. It comes form the quantization of the Knizhnik-Zamolodchikov- Bernard equation on the torus. The relation with elliptic IRF models is explained.

J. M. Figueroa-O&#39;Farrill

This is an expository talk about the relation between gauging the WZ term of a one-dimensional sigma-model with a symplectic target and the existence of an equivariant moment mapping for symplectic group actions. The punch line is that the obstructions for gauging coincide with the obstructions for the existence of the moment mapping. This paper can be thoug