February 1997 arXiv papers — page 3

Narcisse Randrianantoanina, Elias Saab

Let $X$ be a Banach space $E$ a Köthe function space that does not contain $c_0$. It is shown that the vector valued function space $E(X)$ has the Near Radon Nikodym property if and only if $X$ does.

P. Di Francesco

We propose a generalization of meanders, i.e., configurations of non-selfintersecting loops crossing a line through a given number of points, to SU(N). This uses the reformulation of meanders as pairs of reduced elements of the Temperley-Lieb algebra, a SU(2)-related quotient of the Hecke algebra, with a natural generalization to SU(N). We also derive explic

Andreas Karch

Starting from a generalization of a recent result on self-duality we systematically analyze self-dual models. We find a criterion to judge whether a given model is self-dual or not. With this tool we construct some new self-dual pairs, focussing on examples with exceptional gauge groups.

G. Barnich, R. Fulp, T. Lada, J. Stasheff

A general construction of an sh Lie algebra from a homological resolution of a Lie algebra is given. It is applied to the space of local functionals equipped with a Poisson bracket, induced by a bracket for local functions along the lines suggested by Gel'fand, Dickey and Dorfman. In this way, higher order maps are constructed which combine to form an sh

Mitsuo Abe, Noboru Nakanishi

It was found in the two-dimensional quantum gravity both in the de Donder gauge and in the lightcone gauge that one of field equations breaks down at the level of the representation, though the breakdown is very little. It is shown that this anomalous behavior occurs also in a very simple model analogous to the lightcone-gauge two-dimensional quantum gravity

Noboru Kawamoto, Kazuhiko Suehiro, Takuya Tsukioka, Hiroshi Umetsu

We investigate the quantization of two-dimensional version of the generalized Chern-Simons actions which were proposed previously. The models turn out to be infinitely reducible and thus we need infinite number of ghosts, antighosts and the corresponding antifields. The quantized minimal actions which satisfy the master equation of Batalin and Vilkovisky hav

Joao M. Soares, Tibor Torma

We calculate the branching ratio for B -> J/psi + anything, within the color-singlet approximation for J/psi production, but including perturbative QCD corrections beyond the leading logarithm approximation. Such higher order corrections are necessary, in order to obtain a result that is not strongly dependent on the renormalization scale. As in the earlier

Silas R. Beane

If the mechanism responsible for the smallness of the vacuum energy is consistent with local quantum field theory, general arguments suggest the existence of at least one unobserved scalar particle with Compton wavelength bounded from below by one tenth of a millimeter. We show that this bound is saturated if vacuum energy is a substantial component of the e

G. Bottazzi, G. Marchesini, G. P. Salam, M. Scorletti

We compute the gluon distribution in deep inelastic scattering at small x by solving numerically the angular ordering evolution equation. The leading order contribution, obtained by neglecting angular ordering, satisfies the BFKL equation. Our aim is the analysis of the subleading corrections. Although not complete - the exact next-to-leading contribution is

J. L. Diaz-Cruz, M. A. Perez, J. J. Toscano

We study the possibility to detect heavy physics effects in the interactions of Higgs bosons and the top quark at future colliders using the effective Lagrangian approach. The modification of the interactions may enhance the production of Higgs bosons at hadron colliders through the mechanisms of gluon fusion and associated production with a W boson or $t\ba

Ralf Hempfling

We have studied the predictions for the LSP decay within the framework of a radiatively broken unified supergravity model without R-parity. Assuming that Higgs/slepton mixing is the only source of R-parity breaking and responsible for the observed neutrino oscillations we obtain predictons for the LSP life-time and branching fractions.

Gilberto Colangelo, Elisabetta Pallante

We calculate the divergences of the generating functional of quenched Chiral Perturbation Theory to one loop for a generic number of flavours. The flavour number dependence of our result enlightens the mechanism of quark loop cancellation in the quenched effective theory for any Green function or S matrix element. We also apply our results to $ππ$ scattering

Fermilab E706 Collaboration, L. Apanasevich

We present results on the production of high transverse momentum charm mesons in collisions of 515 GeV/c negative pions with beryllium and copper targets. The experiment recorded a large sample of events containing high transverse momentum showers detected in an electromagnetic calorimeter. From these data, a sample of charm mesons has been reconstructed via

CLEO Collaboration, C. P. Jessop

Using data taken with the CLEO II detector, we present the first full angular analysis in the color-suppressed modes B0 --> J/psi K*0 and B+ --> J/psi K*+. This leads to a complete determination of the decay amplitudes of these modes. In addition, we update the branching fractions for B --> J/psi K and B --> J/psi K*.

Francois Goy, Franco Selleri

Traditional clock synchronisation on a rotating platform is shown to be incompatible with the experimentally established transformation of time. The latter transformation leads directly to solve this problem through noninvariant one-way speed of light. The conventionality of some features of relativity theory allows full compatibility with existing experimen

Alexander Gromov, V. Perepelovsky

The quasi-two-dimensional modeling of the small adiabatic perturbation on the background of the stationary configuration of the selfgravitating gas with the weak transverse nonhomogeneity approximation is presented. The space periodic character of the solution of this system is proofed.

John C. Baez

Working in the Palatini formalism, we describe a procedure for constructing degenerate solutions of general relativity on 4-manifold M from certain solutions of 2-dimensional BF theory on any framed surface Sigma embedded in M. In these solutions the cotetrad field e (and thus the metric) vanishes outside a neighborhood of Sigma, while inside this neighborho

Patrick R. Brady, Teviet Creighton, Curt Cutler, Bernard F. Schutz

We investigate the computational requirements for all-sky, all-frequency searches for gravitational waves from spinning neutron stars, using archived data from interferometric gravitational wave detectors such as LIGO. These sources are expected to be weak, so the optimal strategy involves coherent accumulaton of signal-to-noise using Fourier transforms of l

Allen E. Everett, Thomas A. Roman

The ``warp drive'' metric recently presented by Alcubierre has the problem that an observer at the center of the warp bubble is causally separated from the outer edge of the bubble wall. Hence such an observer can neither create a warp bubble on demand nor control one once it has been created. In addition, such a bubble requires negative energy densi

G. Giachetta, L. Mangiarotti, G. Sardanashvily

The usual formulations of time-dependent mechanics start from a given splitting $Y=R\times M$ of the coordinate bundle $Y\to R$. From physical viewpoint, this splitting means that a reference frame has been chosen. Obviously, such a splitting is broken under reference frame transformations and time-dependent canonical transformations. Our goal is to formulat

Don H. Kim, Patrick A. Lee, Xiao-Gang Wen

We study 2+1 dimensional massless Dirac fermions and bosons coupled to a U(1) gauge field as a model for underdoped cuprates. We find that the uniform susceptibility and the specific heat coefficient are logarithmically enhanced (compared to linear-in-T behavior) due to the fluctuation of transverse gauge field which is the only massless mode at finite boson

M. A. Muñoz, T. Hwa

Nonlinear diffusion is studied in the presence of multiplicative noise. The nonlinearity can be viewed as a ``wall'' limiting the motion of the diffusing field. A dynamic phase transition occurs when the system ``unbinds'' from the wall. Two different universality classes, corresponding to the cases of an ``upper'' and a ``lower'&

Norbert Schultka, Efstratios Manousakis

We have studied the superfluid density and the specific heat of the XY model on lattices L x L x H with L >> H (i.e. on lattices representing a film geometry) using the Cluster Monte Carlo method. In the H-direction we applied staggered boundary conditions so that the order parameter on the top and bottom layers is zero, whereas periodic boundary conditions

Beat Frischmuth, Manfred Sigrist

Using the Continuous Time Quantum Monte Carlo Loop algorithm, we calculate the temperature dependence of the uniform susceptibility, and the specific heat of a spin-1/2 chain with random antiferromagnetic and ferromagnetic couplings, down to very low temperatures. Our data show a consistent scaling behavior in both quantities and support strongly the conject

Kazuhiko Kuroki, Ryotaro Arita, Hideo Aoki

The ground state of a one-dimensional Hubbard model having the next-nearest neighbor hopping (t') as well as the nearest-neighbor one (t) is numerically investigated at half-filling. A quantum Monte Carlo result shows a slowly decaying pairing correlation for a sizeable interaction strength $(U \leq 2t)$, while the system is shown to become insulating fo

E. Brezin, S. Hikami

Dyson's short-distance universality of the correlation functions implies the universality of P(s), the level-spacing distribution. We first briefly review how this property is understood for unitary invariant ensembles and consider next a Hamiltonian H = H_0+ V , in which H_0 is a given, non-random, N by N matrix, and V is an Hermitian random matrix with

Hidekatsu Suzuura, Naoto Nagaosa

The implications of the angle-resolved photoemission spectroscopy (ARPES) on the issue of spin-charge separation are discussed from the viewpoint of slave-particle RVB theories. It is pointed out that the non-local phase string is essential to reproduce the two-peak structure experimentally observed in SrCuO_2. The comparison between 1D and 2D cases is also

Leonid P. Pryadko

I analyze non-local symmetries of finite-size Euclidean 3D lattice Chern-Simons models in the presence of an external magnetic field and non-zero average current. It is shown that under very general assumptions the particle-vortex duality interchanges the total Euclidean magnetic flux Phi/(2 Pi) and the total current I in a given direction, while the flux at

Dragomir R. Radev, Kathleen R. McKeown

In this paper, we describe a method for automatic creation of a knowledge source for text generation using information extraction over the Internet. We present a prototype system called PROFILE which uses a client-server architecture to extract noun-phrase descriptions of entities such as people, places, and organizations. The system serves two purposes: as

R. Brent Tully, Marc A. W. Verheijen

A cluster sample of 62 galaxies complete to M(B)=-16.5 mag has been observed at B,R,I,K' bands with imaging detectors. The distribution of exponential disk central surface brightnesses is found to be bimodal. The bimodality is particularly significant at K' because obscuration is not a problem and because the high surface brightness galaxies are redd

L. J. Greenhill, J. M. Moran, J. R. Herrnstein

We present the first interferometer map of the water maser emission in the active nucleus of NGC 4945. Although the declination of the galaxy is about -49 degrees, we were able to make the observations with the southernmost antennas of the Very Long Baseline Array. Strong maser emission is present in three velocity ranges, one near the systemic velocity and

Christopher W. Mauche, John C. Raymond

We present an observational and theoretical review of the winds of cataclysmic variables (CVs). Specifically, we consider the related problems of the geometry, ionization state, and mass-loss rate of the winds of CVs. We present evidence of wind variability and discuss the results of studies of eclipsing CVs. Finally, we consider the properties of accretion

H. J. Mo

We discuss some recent progress in constructing analytic approximations to the galaxy clustering. We show that successful models can be constructed for the clustering of both dark matter and dark matter haloes. Our understanding of galaxy clustering and galaxy biasing can be greatly enhanced by these models.

R. A. Johnson, A. Lawrence, R. Terlevich, D. Carter

We present the results of BVRI imaging and optical spectroscopy of the dwarf galaxy A0951+68. The images reveal that, although this galaxy is classified as a dwarf elliptical, it has some properties that are similar to dwarf irregular galaxies. It contains two bright knots of emission, one of which is red and unresolved and the other blue and resolved. The b

A. Ratcliffe, T. Shanks, Q. A. Parker, R. Fong

We present the results for the galaxy luminosity function as estimated from the Durham/UKST Galaxy Redshift Survey. This survey is magnitude limited to bj = 17, contains 2500 galaxies sampled at a rate of one in three and surveys a 4 x 10^6 Mpc^3 volume of space. The maximum likelihood parameters for a standard Schechter luminosity function are estimated to

R. de Grijs, R. F. Peletier

We present the results of a detailed study of vertical surface brightness profiles of edge-on disk galaxies. Although the exponential disk scale height is constant to first order approximation, we show that for the large majority of galaxies in our sample, the scale height increases with distance along the major axis. The effect is strongest for early-type g

Simon D. M. White

A standard paradigm is now available for the recent evolution (z < 10) of structure on galactic and larger scales. Most of the matter is assumed to be dark and dissipationless and to cluster hierarchically from gaussian initial conditions. Gas moves under the gravitational influence of this dark matter, settling dissipatively at the centres of dark halos to

M. Balucinska-Church, T. Takahashi, Y. Ueda, M. J. Church

We report the discovery of the cessation of flickering in dips in the black hole candidate Cygnus X-1, detected for the first time in the ASCA observation of May 9th., 1995. During this observation, particularly deep dipping took place resulting in strong changes in hardness ratio corresponding to absorption of the power law spectral component. The deadtime

J. Richard Bond, Dmitry Pogosyan, Tarun Souradeep

The (large angle) COBE DMR data can be used to probe the global topology of our universe on scales comparable to and just beyond the present ``horizon&#39;&#39;. For compact topologies, the two main effects on the CMB are: [1] the breaking of statistical isotropy in characteristic patterns determined by the photon geodesic structure of the manifold and [2] a

Paolo Ciafaloni, Alex Pomarol

Considering the supersymmetric Higgs mass ($μ$-parameter) as a dynamical variable to be determined by minimizing the energy, we predict its value as a function of the soft masses of the potential. We find that $μ$ has a nonzero value close to the weak scale. This scenario offers a simultaneous solution to the doublet-triplet splitting problem and to the $μ$-

Juan Garcia-Bellido

We study the large scale power spectrum of gravitational wave perturbations of the microwave background in the context of single-bubble open inflation models. We compute the ratio of tensor to scalar contributions to the CMB anisotropies as a function of $Ω_0$, the spectral index $n_S$ and the tunneling parameter $2πGS_1/H$. We find that gravitational wave a

J. Binnewies, B. A. Kniehl, G. Kramer

We present new sets of fragmentation functions for D^{*+-} mesons, both at leading and next-to-leading order. They are determined by fitting LEP1 data on inclusive D^{*+-} production in e^+e^- annihilation. In one of the sets, we take the charm-quark fragmentation function to be of the form proposed by Peterson et al. and thus obtain updated values of the ep

Andrew D. Jacobs, J. F. Cornwell

We introduce a new class of 2-cocycles defined explicitly on the generators of certain multiparameter standard quantum groups. These allow us, through the process of twisting the familiar standard quantum groups, to generate new as well as previously known examples of non-standard quantum groups. In particular we are able to construct generalisations of both

Jacques Demaret, Michael Heller, Dominique Lambert

The essence of the method of physics is inseparably connected with the problem of interplay between local and global properties of the universe. In the present paper we discuss this interplay as it is present in three major departments of contemporary physics: general relativity, quantum mechanics and some attempts at quantizing gravity (especially geometrod

A. Agodi, G. Andronico, P. Cea, M. Consoli

There are two physically different interpretations of ``triviality&#39;&#39; in $(λΦ^4)_4$ theories. The conventional description predicts a second-order phase transition and that the Higgs mass $m_h$ must vanish in the continuum limit if $v$, the physical v.e.v, is held fixed. An alternative interpretation, based on the effective potential obtained in ``tri

Ashoke Sen

We show how an F-theory compactified on a Calabi-Yau (n+1)-fold in appropriate weak coupling limit reduces formally to an orientifold of type IIB theory compactified on an auxiliary complex n-fold. In some cases (but not always) if the original (n+1)-fold is singular, then the auxiliary n-fold is also singular. We illustrate this by analysing F-theory on ell

Frank Ferrari

It is shown that all the (p,q) dyon bound states exist and are unique in N=4 and N=2 with four massless flavours supersymmetric SU(2) Yang-Mills theories, where p and q are any relatively prime integers. The proof can be understood in the context of field theory alone, and does not rely on any duality assumption. We also give a general physical argument show

Nobuyoshi Ohta

We give a model-independent derivation of general intersecting rules for non-extreme $p$-branes in arbitrary dimensions $D$. This is achieved by directly solving bosonic field equations for supergravity coupled to a dilaton and antisymmetric tensor fields with minimal ansätze. We compare the results with those in eleven-dimensional supergravity. Supersymmetr

Xi Dai, Zhao-bin Su, Lu Yu

The coexistence of $π$-flux state and d-wave RVB state is considered in this paper within the slave boson approach. A critical value of doping concentration $δ_c$ is found, below which the coexisting $π$-flux and d-wave RVB state is favored in energy. The pseudo Fermi surface of spinons and the physical electron spectral function are calculated. A clear Ferm

Takuji Tsujimoto, Yuzuru Yoshii, Ken&#39;ichi Nomoto, Francesca Matteucci

Oxygen to iron abundance ratios of metal-poor stars provide information on nucleosynthesis yields from massive stars which end in Type II supernova explosions. Using a standard model of chemical evolution of the Galaxy we have reproduced the solar neighborhood abundance data and estimated the oxygen and iron yields of genuine SN II origin. The estimated yiel

A. A. Tseytlin

We give an overview of various composite BPS configurations of string theory and M-theory p-branes represented as classical supergravity solutions. Type II string backgrounds can be obtained by S- and T- dualities from NS-NS string - 5-brane configurations corresponding to exact conformal sigma models. The single-center solutions can be also generated from t

C. Morosi, G. Tondo

Two quasi--biHamiltonian systems with three and four degrees of freedom are presented. These systems are shown to be separable in terms of Nijenhuis coordinates. Moreover the most general Pfaffian quasi-biHamiltonian system with an arbitrary number of degrees of freedom is constructed (in terms of Nijenhuis coordinates) and its separability is proved.

Holger Lyre

The understanding of the meaning of quantization seems to be the main problem in understanding quantum structures. In this paper first the difference between quantized particle vs. radiation fields in the formalism of canonical quantization is discussed. Next von Weizsaecker&#39;s concept of &#39;&#39;multiple quantization&#39;&#39; which leads to an underst

Francisco J. Herranz, Mariano Santander

A complete choice of generators of the center of the enveloping algebras of real quasi-simple Lie algebras of orthogonal type, for arbitrary dimension, is obtained in a unified setting. The results simultaneously include the well known polynomial invariants of the pseudo-orthogonal algebras $so(p,q)$, as well as the Casimirs for many non-simple algebras such

Mariano Santander, Francisco J. Herranz

We introduce three &#34;Cayley-Klein&#34; families of Lie algebras through realizations in terms of either real, complex or quaternionic matrices. Each family includes simple as well as some limiting quasi-simple real Lie algebras. Their relationships naturally lead to an infinite family of $3\times 3$ Freudenthal-like magic squares, which relate algebras in

Francisco J. Herranz, Mariano Santander

The metric structure of homogeneous spaces of rank-one and rank-two associated to the real pseudo-orthogonal groups SO(p,q) and some of their contractions (e.g., ISO(p,q), Newton-Hooke type groups...) is studied. All these spaces are described from a unified setting following a Cayley-Klein scheme allowing to simultaneously study the main features of their R

Luis Gonzalez-Mestres

If textbook Lorentz invariance is actually a property of the equations describing a sector of matter above some critical distance scale, several sectors of matter with different critical speeds in vacuum can coexist and an absolute rest frame (the vacuum rest frame, possibly related to the local rest frame of the expanding Universe) may exist without contrad

J. Ryckebusch, V. Van der Sluys, K. Heyde, H. Holvoet

We present a model to calculate cross sections for electroinduced two-nucleon emission from finite nuclei. Short-range correlations in the wave functions and meson-exchange contributions to the photoabsorption process are implemented. Effects of the short-range correlations are studied with the aid of a perturbation expansion method with various choices of t

Narcisse Randrianantoanina

Let $M$ be a von Neumann algebra with a faithful normal finite trace $t$, and $H^\infty$ be a finite, maximal, subdiagonal of $M$. Fundamental theorems on conjugate functions for weak* Dirichlet algebras are shown to be a bounded linear map from $L^p(M,t)$ into $L^p(M,t)$ for $1<p<\infty$, and to be a continuous linear map from $L^1(M,t)$ into $L^{1,\infty}(

Beata Randrianantoanina

Characterizations are given for 1-complemented hyperplanes of strictly monotone real Lorentz spaces and 1-complemented finite codimensional subspaces (which contain at least one basis element) of real Orlicz spaces equipped with either Luxemburg or Orlicz norm.

Walter Neumann, Michael Shapiro

Cannon has given an example of a virtually abelian group and a generating set where the full language of geodesics is not regular. We describe a virtually abelian group and a generating set so that no regular language of geodesics surjects to the group.

Alexander A. Vlasov

One more paradox of classical Lorentz-Dirac preaccelerative solution is found: the formation of the event horizon.

Chopin Soo, Lay Nam Chang

We compare the conventional description of the interaction of matter with the four known forces in the standard model with an alternative Weyl description in which the chiral coupling is extended to include gravity. The two are indistinguishable at the low energy classical level of equations of motion, but there are subtle differences at the quantum level wh

S. Pratik Khastgir

The exact factorisable quantum S-matrices are known for simply laced as well as non-simply laced affine Toda field theories. Non-simply laced theories are obtained from the affine Toda theories based on simply laced algebras by folding the corresponding Dynkin diagrams. The same process, called classical `reduction&#39;, provides solutions of a non-simply la

Jens Hoppe

Some exact solutions to the classical matrix model equations that arise in the context of M(embrane) theory are given, and their topological nature is identified.

Klaus Behrndt, Ingo Gaida

We present subleading corrections to the N=2 supersymmetric black hole entropy. These subleading contributions correspond to instanton corrections of the Type II string theory. In particular we consider an axion free black hole solution of low-energy effective Type II string theory. We present a procedure to include successively all instanton corrections. Ex

Pietro Fré

In this lecture I review recent results on the use of Solvable Lie Algebras as an efficient description of the scalar field sector of supergravities in relation with their non perturbative structure encoded in the U-duality group. I also review recent results on the construction of BPS saturated states as solution of the first differential equations followin

Jan de Boer, Kentaro Hori, Yaron Oz, Zheng Yin

We use brane configurations and SL(2,Z) symmetry of the type IIB string to construct mirror N=2 supersymmetric gauge theories in three dimensions. The mirror map exchanges Higgs and Coulomb branches, Fayet-Iliopoulos and mass parameters and U(1)R symmetries. Some quantities that are determined at the quantum level in one theory are determined at the classica

M. Carena, M. Quiros, A. Riotto, I. Vilja

Electroweak baryogenesis is an interesting theoretical scenario, which demands physics beyond the Standard Model at energy scales of the order of the weak boson masses. It has been recently emphasized that, in the presence of light stops, the electroweak phase transition can be strongly first order, opening the window for electroweak baryogenesis in the MSSM

E. Gedalin, A. Moalem. L. Razdolskaya

The total cross section for the pp --> pp $π^0$ reaction at energies close to threshold is calculated within the frame of a chiral perturbation theory. The tree and one loop diagrams up to chiral order D=2 contributions are taken into account. The $L^{(0)}$ isoscalar-scalar part of t-channel two-pion exchange loop diagrams enhances the production amplitude s

Masahiro Imachi, Takaaki Kakitsuka, Norimasa Tsuzuki, Hiroshi Yoneyama

U(2) lattice gauge theory with $θ$-term in 2 space-time dimensions is investigated. It has non-Abelian real action and Abelian( U(1) type) imaginary action. The imaginary action is defined as the standard $θ$-term. As the effect of renormalization group (RG) transformation, non-Abelian imaginary action is induced. After many steps of RG transformation, non-A

W. Krivan, P. Laguna, P. Papadopoulos, N. Andersson

We present a numerical study of the time evolution of perturbations of rotating black holes. The solutions are obtained by integrating the Teukolsky equation written as a first-order in time, coupled system of equations, in a form that explicitly captures its hyperbolic structure. We address the numerical difficulties of solving the equation in its original

David E. Evans, Yasuyuki Kawahigashi

A. Ocneanu has observed that a mysterious orbifold phenomenon occurs in the system of the M_infinity-M_infinity bimodules of the asymptotic inclusion, a subfactor analogue of the quantum double, of the Jones subfactor of type A_2n+1. We show that this is a general phenomenon and identify some of his orbifolds with the ones in our sense as subfactors given as

Stefan Ivanov, Irina Petrova

A local classification of locally conformal flat Riemannian Einstein-like four-manifolds as well as a local classification of all locally conformal flat Riemannian four-manifolds for which all Jacobi operators have parallel eigenspaces along every geodesic is given. Non-trivial explicit examples are presented. The problem of local description of self-dual Ei

Wolfram Brenig

Magnetic Raman scattering from a frustrated spin-1/2 Heisenberg-chain is considered with a focus on the uniform phase of the spin-Peierls compound CuGeO_3. The Raman intensity is analyzed in terms of a Loudon-Fleury scattering process using a spinless-fermion mean-field theory developed for the frustrated spin-chain. A comparison to experimental data is pres

Ehud Reiter, Alison Cawsey, Liesl Osman, Yvonne Roff

An important part of building a natural-language generation (NLG) system is knowledge acquisition, that is deciding on the specific schemas, plans, grammar rules, and so forth that should be used in the NLG system. We discuss some experiments we have performed with KA for content-selection rules, in the context of building an NLG system which generates healt

Dayton L. Jones, Ann E. Wehrle

We observed the nuclear region of NGC 4261 (3C270) with the VLBA at two frequencies (1.6 and 8.4 GHz) simultaneously. We find that the position angle of the parsec-scale radio axis agrees, within the errors, with the position angle of the VLA-scale jet. Our observations also reveal basically symmetric radio structures at both 1.6 and 8.4 GHz. Analysis of the

F. H. Briggs

The space density of low surface brightness and tiny gas-rich dwarf galaxies are estimated for two recent catalogs: The Arecibo Survey of Northern Dwarf and Low Surface Brightness Galaxies (Schneider, Thuan, Magri & Wadiak 1990) and The Catalog of Low Surface Brightness Galaxy, List II (Schombert, Bothun, Schneider & McGaugh 1992). The goals are (1) to evalu

Carla Maceroni, Slavek M. Rucinski

The photometric data for a short-period (0.1984 day) eclipsing binary V38 discovered by the OGLE micro-lensing team in Baade&#39;s W indow field BW3 have been analyzed. The de-reddened color (V-I_C)_0=2.3 and the light-curve synthesis solution of the I-filter light curve suggest a pair of strongly-distorted M-dwarfs, with parameters between those of YY Gem a

Paul J. Green, Thomas L. Aldcroft, Smita Mathur, Norbert Schartel

Recent results from the ROSAT All Sky Survey, and from deep ROSAT pointings reveal that broad absorption line quasars (BALQSOs) are weak in the soft X-ray bandpass (with optical-to-X-ray spectral slope alpha_{ox}>1.8) in comparison to QSOs with normal OUV spectra (mean alpha_{ox}=1.4). One glaring exception appeared to be the nearby BALQSO PG1416-129, which

Norbert Zacharias

The US Naval Observatory 8--inch astrograph has been equipped with a Kodak 1536x1024 pixel CCD since June 1995, operating in a 570--650 nm bandpass. With 3--minute exposures well exposed images are obtained in the magnitude range $R \approx 8.5 - 13.5^{m}$. An astrometric precision of 10 to 15 mas for those stars is estimated from frame--to--frame comparison

Jaume Garriga, V. F. Mukhanov

In the simplest model of open inflation there are two inflaton fields decoupled from each other. One of them, the tunneling field, produces a first stage of inflation which prepares the ground for the nucleation of a highly symmetric bubble. The other, a free field, drives a second period of slow roll inflation inside the bubble. However, the second field al

E. L. Gubankova, F. Wegner

The infinitesimal unitary transformation, introduced recently by F.Wegner, to bring the Hamiltonian to diagonal (or band diagonal) form, is applied to the Hamiltonian theory as an exact renormalization scheme. We consider QED on the light front to illustrate the method. The low-energy generated interaction, induced in the renormalized Hamiltonian to the orde

Brian Greene

These lectures are devoted to introducing some of the basic features of quantum geometry that have been emerging from compactified string theory over the last couple of years. The developments discussed include new geometric features of string theory which occur even at the classical level as well as those which require non-perturbative effects. These lectur

Zygmunt Lalak

We show that all kinds of biasing of cosmological phase transitions produce qualitatively new type of domain wall networks. The biased networks consist of compact, finite size, bag-like wall structures and exhibit a generic instability. The surface of biased networks disappears exponentially fast after a limited period of scaling. We argue that fluctuations

Thomas Appelquist, Stephen B. Selipsky

We examine the role of instantons in the zero-temperature chiral phase transition in an SU(N) gauge theory. For a range of N_f (the number of fermion flavors) depending on N, the theory exhibits an infrared fixed point at coupling $α_*$. As N_f decreases, $α_*$ increases, and it eventually exceeds a critical value sufficient to trigger chiral symmetry breaki

G. Amelino-Camelia

The finite-temperature effective potential of the O(N) linear σmodel is studied, with emphasis on the implications for the investigation of hot hadron dynamics. The contributions from all the ``bubble diagrams&#39;&#39; are fully taken into account for arbitrary N; this also allows to address some long-standing issues concerning the use of non-perturbative a

V. G. Kovalevich, P. Osland, Ya. M. Shnir, E. A. Tolkachev

The effective Lagrangian of QED coupled to dyons is calculated. The resulting generalization of the Euler-Heisenberg Lagrangian contains non-linear P and T noninvariant terms corresponding to the virtual pair creation of dyons. The corresponding P and T violating part of the matrix element for light-by-light scattering is considered. This effect induces an e

Jian-Jun Yang, Guang-Lie Li

The relationship between the parton transverse momentum and longitudinal momentum, which is obtained by analysing the hadron tensor in the deep inelastic scattering (DIS) process, indicates that the transverse size of partons in a nucleon is sensitively affected by the effective nucleon mass. The change in this transverse size gives rise to an Additional Par

C. Adloff

Measurements of ep scattering with squared 4-momentum transfer Q^2 up to 35000 GeV^2 are compared with the expectation of the standard deep-inelastic model of lepton-nucleon scattering (DIS). For Q^2 > 15000 GeV^2, N_{obs} =12 neutral current candidate events are observed where the expectation is N_DIS = 4.71 \pm 0.76 events. In the same Q^2 range, N_{obs} =

Frank Antonsen, Fotini Markopoulou

A careful study of the induced transformations on spatial quantities due to 4-dimensional spacetime diffeomorphisms in the canonical formulation of general relativity is undertaken. Use of a general formalism, which indicates the role of the embedding variables in a transparent manner, allows us to analyse the effect of 4-dimensional diffeomorphisms more gen

Alex Kamenev, Yuval Gefen

Employing different statistical ensembles may lead to qualitatively different results concerning averages of physical observables on the mesoscopic scale. Here we discuss differences between the canonical and the grandcanonical ensembles due to both quenched disorder and thermodynamical effects. We show how these differences are related to spectral correlati

Nandini Chatterjee, Neelima Gupte

We study spatially periodic orbits for a coupled map lattice of sine circle maps with nearest neighbour coupling and periodic boundary conditions. The stability analysis for an arbitrary spatial period k is carried out in terms of the independent variables of the problem and the stability matrix is reduced to a neat block diagonal form. For a lattice of size

Gabriela Canalizo, Alan Stockton

We present low-resolution absorption-line spectra of three candidate close ( < 3 arcsec) companions to the low redshift QSOs 3CR 323.1, PG 1700+518, and PKS 2135-147. The spectra were obtained with LRIS on the Keck telescopes and with the Faint Object Spectrograph on the University of Hawaii 2.2 m telescope. For 3CR 323.1 and PG 1700+518, we measure relative

Yu Gao, P. M. Solomon, D. Downes, S. J. E. Radford

We have detected extremely wide (1100 km/s) CO(1-0) emission from NGC 1144, an interacting, luminous infrared galaxy that is the dominant component of the Arp 118 system. The observations show that NGC 1144 is one of the most CO luminous galaxies in the local universe, with a CO luminosity twice that of Arp 220. Maps with the IRAM interferometer show that th

Andrew Gould, Piotr Popowski

The distance modulus of a galaxy determined from Cepheids differs from its distance modulus determined from Tully-Fisher by an amount that is proportional to the galaxy&#39;s line width, W: Delta mu ~ (-1.73\pm 0.46)log(W). While a miscalibration of the slope of Tully-Fisher could in principle produce this effect, we argue that such a miscalibration is very

Haiqing Wei, Xin Xue

Tailoring many-body interactions among a proper quantum system endows it with computing ability by means of static quantum computation in the sense that some of the physical degrees of freedom can be used to store binary information and the corresponding binary variables satisfy some given logic relations if and only if the system is in the ground state. Two

Conor Houghton

The construction of new hyper-Kaehler manifolds by taking the infinite monopole mass limit of certain Bogomol&#39;nyi-Prasad-Sommerfield monopole moduli spaces is considered. The one-parameter family of hyperkaehler manifolds due to Dancer is shown to be an example of such manifolds. A new family of fixed monopole spaces is constructed. They are the moduli s

Mohan Narayan, G. Rajasekaran, Rahul Sinha

We investigate the time-of-night variation of solar neutrino rate which will be of relevance to Super-Kamioka and Sudbury neutrino detectors in the framework of oscillations among the three flavors. An analytical method of computing the regeneration in the earth is presented. If day-night effect is seen, we show how the study of the time-of-night variation w

Peter Leifer

In order to prevent ``unavoidable&#39;&#39; break-down of the ``peaceful coexistence&#39;&#39; between foundations of quantum theory and relativity I propose a new type of a quantum gauge theory (superrelativity). This differs from ordinary gauge theories in the sense that the affine connection of this theory is constructed from first derivatives of the Fubi