November 1996 arXiv papers — page 14

A. Canning, G. Galli, J. Kim

Assembling clusters on surfaces has emerged as a novel way to grow thin films with targeted properties. In particular, it has been proposed from experimental findings that fullerenes deposited on surfaces could give rise to thin films retaining the bonding properties of the incident clusters. However the microscopic structure of such films is still unclear.

Simon Kalvoda, Beate Paulus, Peter Fulde, Hermann Stoll

Lattice constants and bulk moduli of eleven cubic III-V semiconductors are calculated using an ab initio scheme. Correlation contributions of the valence electrons, in particular, are determined using increments for localized bonds and for pairs and triples of such bonds; individual increments, in turn, are evaluated using the coupled cluster approach with s

Walter Nadler, Wolfgang Fink

We demonstrate that the fraction of pattern sets that can be stored in single- and hidden-layer perceptrons exhibits finite size scaling. This feature allows to estimate the critical storage capacity α_c from simulations of relatively small systems. We illustrate this approach by determining α_c, together with the finite size scaling exponent ν, for storing

Mitsuru Fujii, Satoshi Fujimoto, Norio Kawakami

We study an integrable spin chain with an alternating array of spins S=1/2, 1 in external magnetic fields using the Bethe ansatz exact solution. The calculated magnetization possesses a cusp structure at a critical magnetic field H=H_{C}, at which the specific heat shows a divergence property. We also calculate finite-size corrections to the energy spectrum,

Aniruddha R. Thakar, Barbara S. Ryden, Katherine P. Jore, Adrick H. Broeils

The Sa(r) galaxy NGC 4138 has been recently found to contain an extensive counterrotating disk which appears to be still forming. Up to a third of the stars in the disk system may be on retrograde orbits. A counterrotating ring of H II regions, along with extended counterrotating H I gas, suggests that the retrograde material has been recently acquired in th

John Feldmeier, Robin Ciardullo, George Jacoby

We report the results of an [O III] lambda 5007 survey for planetary nebulae (PN) in three spiral galaxies: M101 (NGC 5457), M51 (NGC 5194/5195) and M96 (NGC 3368). By comparing on-band/off-band [O III] lambda 5007 images with images taken in H-alpha and broadband R, we identify 65, 64 and 74 PN candidates in each galaxy, respectively. From these data, an ad

H. -W. Rix

Recent results from gravitational lensing are combined with new modeling of the stellar velocity distributions in nearby galaxies to probe the connection between the luminous and the dark matter in elliptical galaxies. From analysing a small number of luminous ellipticals the following picture appears to emerge: (1) the best fitting total mass distribution (

S. N. Zhang

A variety of high energy (>1 keV) spectra have been observed in recent years from Black Hole (BH) and Neutron Star (NS) X-ray Binaries (XB). Some common physical components exist between BHXBs and NSXBs, resulting in some high energy spectral features. A common component between a BHXB and a weakly magnetized NSXB is the inner accretion disk region extending

C. Baccigalupi, L. Amendola, F. Occhionero

We generalize in several ways the results existing in the literature: a) we make use of an exact general relativistic solution for a spherical, nearly empty cavity in the matter dominated era to evaluate the null geodesics and the Sachs-Wolfe effect; b) we evaluate the magnitude of the adiabatic fluctuations of the photon-baryon plasma; c) we study the influ

Matthew A. Bershady

A Tully-Fisher (TF) relation from H-alpha rotation curves of 19 luminous, star-forming galaxies reveals there is little evidence for evolution in the mass-to-light ratio (M/L) of these galaxies to z~0.3. The near-infrared Tolman surface-brightness test for other luminous galaxies indicates their luminosity also is little changed to z~0.3. In this redshift re

Matthew A. Bershady

Motivated by recent pioneering measurements of galaxy kinematics at intermediate redshifts, we have begun a pilot survey to measure rotation curves for blue, star-forming galaxies between 0.05<z<0.35. The scientific impetus for such measurements is to construct internal velocity - luminosity relations at redshifts substantial enough to make cosmological and

F. Zimmer, H. Lesch, G. T. Birk

This paper shows that magnetic reconnection could be an important heating process in cosmic gases. In any volume where magnetized plasmas collide, the dissipation of magnetic energy via reconnection seems to be unavoidable. Since most cosmic plasmas are highly conductive, the magnetic field lines are transported with the gas and no dissipation occurs for the

Shin Sasaki

We propose a new method to estimate cosmological parameters using the baryon fraction of clusters of galaxies for a range of redshifts. The basic assumption is that the baryon fraction of clusters is constant, which is a reasonable assumption when it is averaged within a Mpc scale. We find that the baryon fraction vs. redshift diagram can estimate the cosmol

V. Le Brun, J. Bergeron, P. Boisse, J. -M. Deharveng

We present HST/WFPC2 high-spatial resolution images in the R and B bands of the close environment of the sightlines to seven quasars which spectra show either a damped Ly-alpha absorption line, 21cm absorption, or a very strong MgII/FeII absorption system at intermediate redshifts (0.4 < z < 1). Objects down to about 0.3&#34;, or 2.0 kpc at z=0.6 (H0 = 50 km

A. Bottino, N. Fornengo, G. Mignola, M. Olechowski

It has been conjectured by Ambrosanio, Kane, Kribs, Martin and Mrenna (AKM) that the CDF event $p \bar p \to e^+ e^- γγ+ missing E_T$ is due to a decay chain involving two neutralino states (the lightest and the next-to-lightest ones). The lightest neutralino ($χ_{AKM}$) has been further considered by Kane and Wells as a candidate for cold dark matter. In th

M. Teresa Ceballos, Xavier Barcons, Francisco J. Carrera, .

We have carried out a fluctuation analysis in four bands (R4, R5, R6 and R7 corresponding to 0.44-1.01 keV, 0.56-1.21 keV, 0.73-1.56 keV and to 1.05-2.04 keV respectively) of two very deep ROSAT PSPC observations in directions where the galactic H{\small I} column is minimal. This has enabled us to study the average spectrum of the sources contributing to 0.

Kengo Yamagishi

Self-organization of orientation-wheels observed in the visual cortex is discussed from the view point of topology. We argue in a generalized model of Kohonen&#39;s feature mappings that the existence of the orientation-wheels is a consequence of Riemann-Hurwitz formula from topology. In the same line, we estimate partition function of the model, and show th

N. Dorey, V. V. Khoze, M. P. Mattis

Seiberg and Witten&#39;s proposed solution of N=2 SQCD with N_c=2 and N_F=4 is known to conflict with instanton calculations in three distinct ways. Here we show how to resolve all three discrepancies, simply by reparametrizing the elliptic curve in terms of quantities $τ^0_{eff}$ and $\tilde{u}$ rather than $τ$ and $u = < Tr A^2 > $. SL(2,Z) invariance of t

Marco Serone

We test the conjectured Type I-Heterotic Duality in four dimensions by analyzing a given class of higher derivative F-terms of the form $F_gW^{2g}$, with W the N=2 gravitational superfield. We study a particular dual pair of theories, the O(2,2) heterotic model and a type I model based on the K3 $Z_2$ orbifold theory constructed by Gimon and Polchinski, furt

S. N. Zhang, K. Ebisawa, R. Sunyaev, Y. Ueda

The X-ray/radio transient superluminal jet source GRO J1655-40 was recently suggested to contain a black hole from optical observations. Being a relatively close-by system (d \sim 3.2 kpc), it can likely provide us with rich information about the physics operating in both galactic and extragalactic jet sources. We present the first simultaneous broad band hi

Roy Maartens, George Ellis, Stephen Siklos

In a cosmological context, the electric and magnetic parts of the Weyl tensor, E_{ab} and H_{ab}, represent the locally free curvature - i.e. they are not pointwise determined by the matter fields. By performing a complete covariant decomposition of the derivatives of E_{ab} and H_{ab}, we show that the parts of the derivative of the curvature which are loca

V. Pirronello, Chi Liu, Liyong Shen, Gianfranco Vidali

We report on the first results of experiments to measure the recombination rate of hydrogen on surfaces of astrophysical interest. Our measurements give lower values for the recombination efficiency (sticking probability S x probability of recombination upon H-H encounter $γ$) than model-based estimates. We propose that our results can be reconciled with ave

Franz Embacher

Considering quantum cosmological minisuperspace models with positive potential, we present evidence that (i) despite common belief there are perspectives for defining a unique, naturally preferred decomposition of the space H of wave functions into two subspaces H^\pm that generalizes the concept of positive and negative frequency, and that (ii) an underlyin

H. R. Karadayi, M. Gungormez

It is given a way of computing Casimir eigenvalues for Weyl orbits as well as for irreducible representations of Lie algebras. A kappa(s) number of polinomials which depend on rank N are obtained explicitly for A_N Casimir operators of order s where kappa(s) is the number of partitions of s into positive integers except 1. It is also emphasized that these ei

J. Czyzewski, J. Kwiecinski, L. Motyka, M. Sadzikowski

Theory and phenomenology of the eta_c photo- and electroproduction is developed from the point of view of probing the odderon singularity in QCD which corresponds to the three gluon exchange mechanism. This mechanism leads to the cross-sections which are independent of W^2 for the exchange of three non-interacting gluons or exhibit increase with increasing W

L. Andrianopoli, R. D&#39;Auria, S. Ferrara, P. Fré

We consider the group theoretical properties of R--R scalars of string theories in the low-energy supergravity limit and relate them to the solvable Lie subalgebra $\IG_s\subset U$ of the U--duality algebra that generates the scalar manifold of the theory: $\exp[\IG_s]= U/H$. Peccei-Quinn symmetries are naturally related with the maximal abelian ideal ${\cal

Randall D. Kamien

I propose a double-twist texture with local smectic order, which may have been seen in recent experiments. As in the Renn-Lubensky TGB phase, the smectic order is broken only through a lattice of screw dislocations. A melted lattice of screw dislocations can produce a double-twist texture as can an unmelted lattice. In the latter case I show that geometry on

Frank Ferrari

I review, with some pedagogy, two different approaches to the computation of BPS spectra in N=2 supersymmetric QCD with gauge group SU(2). The first one is semiclassical and has been widely used in the literature. The second one makes use of constraints coming from the non perturbative, global structure of the Coulomb branch of these theories. The second met

Ivan K. Kostov, Matthias Staudacher

We formulate and solve a class of two-dimensional matrix gauge models describing ensembles of non-folding surfaces covering an oriented, discretized, two-dimensional manifold. We interpret the models as string theories characterized by a set of coupling constants associated to worldsheet ramification points of various orders. Our approach is closely related

V. V. Konotop, M. Salerno

A detailed analysis of the small-amplitude solutions of a deformed discrete nonlinear Schrödinger equation is performed. For generic deformations the system possesses &#34;singular&#34; points which split the infinite chain in a number of independent segments. We show that small-amplitude dark solitons in the vicinity of the singular points are described by

Rod Halburd, Nalini Joshi

In this paper, we study a well known asymptotic limit in which the second Painlevé equation (P_II) becomes the first Painlevé equation (P_I). The limit preserves the Painlevé property (i.e. that all movable singularities of all solutions are poles). Indeed it has been commonly accepted that the movable simple poles of opposite residue of the generic solution

Tad Hogg

A quantum algorithm for combinatorial search is presented that provides a simple framework for utilizing search heuristics. The algorithm is evaluated in a new case that is an unstructured version of the graph coloring problem. It performs significantly better than the direct use of quantum parallelism, on average, in cases corresponding to previously identi

M. M. Kapranov

This is an attempt to generalize some basic facts of homological algebra to the case of &#34;complexes&#34; in which the differential satisfies the condition $d^N=0$ instead of the usual $d^2=0$. Instead of familiar sign factors, the constructions related to such &#34;N-complexes&#34; involve powers of q where q is a primitive Nth root of 1. We show that the

M. Bordemann, S. Waldmann

In this contribution we review the formal GNS construction developped in a previous preprint (q-alg/9607019), and formulate the usual WKB-expansion in flat 2n-dimensional phase space in terms of a GNS construction with a positive linear functional with support on a projectable Lagrangean submanifold defined as a graph of an exact one form dS. The main trick

Denis V. Juriev

This short paper being devoted to some aspects of the inverse problem of the representation theory treats several themes, which have their origins in the researches of F.A.Berezin, D.P.Zhelobenko, V.P.Maslov and his group, in context of the author&#39;s approach to the setting free of hidden symmetries, which is based on the noncommutative geometry. Relation

M. Marinescu, A. Dalgarno, J. F. Babb

The retarded long-range potentials for hydrogen and alkali-metal atoms in their ground states and a perfectly conducting wall are calculated. The potentials are given over a wide range of atom-wall distances and the validity of the approximations used is established.

D. Hüber, H. Kamada, H. Witała, W. Glöckle

A new, more efficient approach to include a three nucleon force into three-nucleon continuum calculations is presented. Results obtained in the new and our old approach are compared both for elastic nucleon-deuteron scattering as well as for the breakup process. The advantages of the new scheme are discussed.

Il-Tong Cheon

When a hydrogen atom trapped in finite space formed by two parallel perfectly conducting plates, the transition rates can be modified. Life-time of the hydrogen $2P_{1/2}$-state is estimated to be shorter as much as $56.3ps $ with a separation distance of $b = 1.2 μm$ between two plates. Although the modification is dependent on position of the atom, the lif

Ilya Kapovich

In this paper we prove that C(4)-T(4)-P, C(3)-T(6)-P and C(6)-P small cancellation groups are translation dis crete in the strongest possible sense and that in these groups for any $g$ and any $n$ there is an algorithm deciding whether or not the equation $ x^n=g$ has a solution. There is also an algorithm for calculating for each $g$ the maximum $n$ such th

Gerald Dunne

We evaluate the exact $QED_{2+1}$ effective action for fermions in the presence of a family of static but spatially inhomogeneous magnetic field profiles. This exact result yields an all-orders derivative expansion of the effective action, and indicates that the derivative expansion is an asymptotic, rather than a convergent, expansion.

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

A method is presented by which a hidden N=2 superconformal symmetry can be exhibited in a string theory or indeed in a topological conformal field theory. More precisely, we present strong evidence, based on calculations with string theories, in favour of the conjecture that any topological conformal field theory can be obtained by twisting an N=2 superconfo

Francesco Fucito, Maurizio Martellini, Mauro Zeni

The vev&#39;s of the magnetic order-disorder operators in QCD are found in an explicit calculation using the first order formulation of Yang-Mills theory.

A. Pasquinucci, K. Roland

We discuss the role of the CPT transformation in first quantized string theories, both on the world-sheet and in the space-time. We explicitly show that the space-time CPT theorem holds for all first-quantized (perturbative) string theories in a Minkowski background of even dimension $D>2$.

Jorgen Randrup

A simple approximate treatment of statistical equilibrium is developed within the linear sigma sigma model by means of the Hartree factorization technique, providing a simple means for sampling initial configurations of the chiral field. These are then subjected to pseudo-expansions and their non-equilibrium relaxation towards the normal vacuum is studied.

P. Hernandez, N. Rius

We investigate the possibility that baryogenesis occurs during the weak phase transition in a minimal extension of the Standard Model which contains extra neutral leptons and conserves total lepton number. The necessary CP-violating phases appear in the leptonic Yukawa couplings. We compute the CP-asymmetries in both the neutral and the charged lepton fluxes

Gunnar S. Bali, A. Wachter, K. Schilling

We present results on (order v^2) QCD interquark potentials from SU(3) lattice simulations on volumes of up to 32^4 lattice sites at beta = 6.2 and beta = 6.0. Preliminary results on quarkonia spectra as obtained from these potentials are presented.

G. J. Gounaris, D. T. Papadamou, F. M. Renard

In the present paper we explore various dynamical scenarios for New Physics (NP) which could be generated by very heavy particles and observed in the form of non-standard &#34;low energy&#34; interactions affecting the scalar sector, the gauge bosons and the quarks of the third family. Such interactions have been previously expressed in terms of 48 CP-conser

X. Q. Li, B. S. Zou

We evaluate the contribution of the final state interaction (FSI) due to single pion exchange inelastic scattering for $D^+\rightarrow \bar {K}^{0*}π^+$ and $D^+\rightarrow \bar K^0ρ^+$ processes. The effects are found to be very significant. The hadronic matrix elements of the weak transition are calculated in terms of the heavy quark effective theory (HQET

D. V. Bugg, B. S. Zou

Data on $J/Ψ\to γ(ρρ)$ demand a broad $0^-$ $ρρ$ signal, attributable to a glueball with a mass of 1750--2100 MeV. Decays of this broad state to $ρρ$, $ωω$, $K^*\bar K^*$ and $ϕϕ$ channels agree well with flavour blindness. The narrow $ι(1440)$ may be attributed to mixing between the glueball and the $s\bar s$ radial excitation. The latter is pushed down in

M. Miyama

$Q^2$ evolution of structure functions in the nucleon and nuclei is investigated by using usual DGLAP equations and parton-recombination equations. Calculated results for proton&#39;s $F_2$ and for the ratio $F_2^{Ca}/F_2^D$ are compared with various experimental data. Furthermore, we study nuclear dependence of $Q^2$ evolution in tin and carbon nuclei: $\pa

Hong Liu, Glenn D. Starkman, Tanmay Vachaspati

The family replication problem is addressed in the context of the dual standard model. The breaking of a simple grand unified group to $[G_{low} \times H_1 \times H_2 \times H_3]/Z_5^3$ and then further to $G_{low}$, produces a spectrum of stable monopoles that fall in three families each of whose magnetic quantum numbers correspond to the electric charges o

R. B. Mann, T. Ohta

We present the exact solution of two-body motion in (1+1) dimensional dilaton gravity by solving the constraint equations in the canonical formalism. The determining equation of the Hamiltonian is derived in a transcendental form and the Hamiltonian is expressed for the system of two identical particles in terms of the Lambert $W$ function. The $W$ function

John D. Barrow, Kerstin E. Kunze

We present new exact inhomogeneous vacuum cosmological solutions of Einstein&#39;s equations. They provide new information about the nature of general cosmological solutions to Einstein&#39;s equations.

M. Bruni, H. van Elst, C. Uggla

After a brief overview of the so-called silent models and their present status, we consider the subclass of Bianchi Type--I models with a magnetic field source. Due to the presence of the magnetic field, the initial singularity shows ``oscillatory&#39;&#39; features reminiscent of the Bianchi Type--IX case. The Bianchi Type--I models with a magnetic field ar

Mauricio Cataldo, Patricio Salgado

Recently M. Kamata and T. Koikawa claimed to obtain the charged version of the spinning BTZ black hole solution by assuming an (anti-) self dual condition imposed on the orthonormal basis components of the electric and magnetic fields. We point out that the Kamata-Koikawa field is not a solution of the Einstein-Maxwell equations and we find the correct solut

Tad Hogg, Bernardo A. Huberman

Smart matter consists of many sensors, computers and actuators embedded within materials. These microelectromechanical systems allow properties of the materials to be adjusted under program control. In this context, we study the behavior of several organizations for distributed control of unstable physical systems and show how a hierarchical organization is

D. A. W. Hutchinson, E. Zaremba, A. Griffin

We present a detailed study of the temperature dependence of the condensate and noncondensate density profiles of a Bose-condensed gas in a parabolic trap. These quantitites are calculated self-consistently using the Hartree-Fock-Bogoliubov equations within the Popov approximation. Below the Bose-Einstein transition the excitation frequencies have a realtive

David Lancaster, Felix Ritort

By numerically solving the Schröedinger equation for small sizes we investigate the quantum critical point of the infinite-range Ising spin glass in a transverse field at zero temperature. Despite its simplicity the method yields accurate information on the value of the critical field and critical exponents. We obtain $Γ_c=1.47\pm 0.01$ and check that expone

K. Park, B. Kahng

We study an anomalous behavior of the height fluctuation width in the crossover from random to coherent growths of surface for a stochastic model. In the model, random numbers are assigned on perimeter sites of surface, representing pinning strengths of disordered media. At each time, surface is advanced at the site having minimum pinning strength in a rando

V. B. Priezzhev, Deepak Dhar, Abhishek Dhar, Supriya Krishnamurthy

We propose a new model of self-organized criticality. A particle is dropped at random on a lattice and moves along directions specified by arrows at each site. As it moves, it changes the direction of the arrows according to fixed rules. On closed graphs these walks generate Euler circuits. On open graphs, the particle eventually leaves the system, and a new

V. N. Muthukumar, Claudius Gros, Roser Valenti, M. Weiden

We present a mean field solution of the antiferromagnetic Heisenberg chain with nearest (J_1) and next to nearest neighbor (J_2) interactions. This solution provides a way to estimate the effects of frustration. We calculate the temperature-dependent spin-wave velocity, v_s(T) and discuss the possibility to determine the magnitude of frustration J_2/J_1 pres

Viktor Dotsenko, Marc Mezard

We present a new method to study disordered systems in the low temperature limit. The method uses the replicated Hamiltonian. It studies the saddle points of this Hamiltonian and shows how the various saddle point contributions can be resummed in order to obtain the scaling behaviour at low temperatures. In a large class of strongly disordered systems, it is

C. Andraud, A. Beghdadi, E. Haslund, R. Hilfer

A rigorous connection is established between the local porosity entropy introduced by Boger et al. (Physica A 187, 55 (1992)) and the configurational entropy of Andraud et al. (Physica A 207, 208 (1994)). These entropies were introduced as morphological descriptors derived from local volume fluctuations in arbitrary correlated microstructures occuring in por

Mark D. Gould, Ioannis Tsohantjis, Jon R. Links, Yao-Zhong Zhang

We describe the twisted affine superalgebra $sl(2|2)^{(2)}$ and its quantized version $U_q[sl(2|2)^{(2)}]$. We investigate the tensor product representation of the 4-dimensional grade star representation for the fixed point subsuperalgebra $U_q[osp(2|2)]$. We work out the tensor product decomposition explicitly and find the decomposition is not completely re

Y. -K. Zhou, M. T. Batchelor

The integrable quantum group $spl_q(2,1)$-invariant supersymmetric t-J model with open boundaries is studied via an analytic treatment of the Bethe equations. An $su(2)$ feature is seen to hold for states at or close to half-filling. For these states the eigenvalues of the transfer matrix of the t-J model satisfy a set of $su(2)$ functional relations. The fi

U. Smilansky

New insight into the correspondence between Quantum Chaos and Random Matrix Theory is gained by developing a semiclassical theory for the autocorrelation function of spectral determinants. We study in particular the unitary operators which are the quantum versions of area preserving maps. The relevant Random Matrix ensembles are the Circular ensembles. The r

S. Kettemann, D. Klakow, U. Smilansky

The autocorrelation function of spectral determinants is proposed as a convenient tool for the characterization of spectral statistics in general, and for the study of the intimate link between quantum chaos and random matrix theory, in particular. For this purpose, the correlation functions of spectral determinants are evaluated for various random matrix en

N. R. Tanvir

We review the use of Cepheids as distance indicators with particular emphasis on the methods which have been applied to HST observations of Cepheids. The calibration of the period-luminosity relations is examined in detail and we identify possible problems with the existing calibrations. New V- and I-band period luminosity relations are presented based on a

D. R. Garnett, E. D. Skillman, R. J. Dufour, G. A. Shields

We present new measurements of the gas-phase C/O abundance ratio in both the NW and SE components of the extremely metal-poor dwarf irregular galaxy I Zw 18, based on ultraviolet spectroscopy of the two H II regions using the Faint Object Spectrograph on the Hubble Space Telescope. We determine values of log C/O = -0.63 +/- 0.10 for the NW component and log

Sidney van den Bergh

Data are presently available on 156 supernovae (SNe) of known type that have occurred in spirals of types Sa-Sc having inclinations i < 70 degrees. The surface density distribution of SN Ibc + SN II is found to be an exponential with exponent -4.5 r(SN) / R(25) . Available data suggest, but do not yet prove, that SNe Ibc may be more centrally concentrated th

Eric P. Smith, R. C. Bohlin, G. D. Bothun, R. W. O&#39;Connell

We present images from the Ultraviolet Imaging Telescope of the Abell 1795 cluster of galaxies. We compare the cD galaxy morphology and photometry of these data with those from existing archival and published data. The addition of a far--UV color helps us to construct and test star formation model scenarios for the sources of UV emission. Models of star form

Tomasz Bulik, M. Coleman Miller

The association of all three soft gamma-ray repeaters (SGRs) with supernova remnants has established that SGRs are young neutron stars, and has given us a starting point for detailed modeling. One of the most popular classes of models involves strongly magnetised neutron stars, with surface dipole fields B~ 10^{14}-10^{15} Gauss. In such strong magnetic fiel

S. K. Chakrabarti

We extend our previous studies of shock waves and shock-free solutions in thin accretion and winds in pseudo-Newtonian geometry to the case when the flow is ``two-dimensional&#39;&#39; and around a ``Kerr black hole&#39;&#39;. We present equations for fully general relativistic viscous transonic flows and classify the parameter space according to whether or

Sandip K. Chakrabarti

We present fully general relativistic equations governing viscous transonic flows in vertical equilibrium in Kerr geometry. We find the complete set of global solutions (both for Optically thick and optically thin flows) in the weak viscosity limit. We show that for a large region of parameter space, centrifugal pressure supported standing shocks can form in

S. K. Chakrabarti, L. Titarchuk, D. Kazanas, K. Ebisawa

We present spectral properties of an accretion disk model, in which a Keplerian accretion disk is flanked by a sub-Keplerian halo component terminating at a standing shock. The post-shock region (which may be considered to be the boundary layer of a black hole) reprocesses the soft photons emitted from the Keplerian accretion disk. We show that switching of

Lex Kaper, Jacco van Loon, Thomas Augusteijn, Paul Goudfrooij

We report the discovery of a symmetric bow shock around the well-known high-mass X-ray binary (HMXB) Vela X-1. Wind bow shocks are a ubiquitous phenomenon around OB-runaway stars, but now such a structure is found around a HMXB. The presence of a bow shock indicates that the system has a high (supersonic) velocity with respect to the interstellar medium. Fro

F. R. Ferraro, E. Carretta, C. E. Corsi, F. Fusi Pecci

We present BVI CCD photometry for more than 10,000 stars in the innermost region (0.3&#39; < r <~ 4&#39;) of the globular cluster M 3. When added to the previous photographic photometry by Buonanno et al. (1994) reaching as far as r ~ 7&#39;, this results in an homogeneous data-set including about 19,000 stars measured in this cluster, which can be now regar

Mariano Mendez, Michiel van der Klis

We have studied the fast timing and spectral behavior of the black hole candidate (BHC) GX 339-4 using all 1 - 20 keV EXOSAT ME data: the July 1983, March 1984, May 1984 and April 1985 observations. In April 1985 GX 339-4 was in a weak low state (0.03E-9 erg cm^{-2} s^{-1}, 2 - 10 keV). The X-ray spectrum was a hard power law with a photon index αof 1.82 and

Arnon Dar

The $^8$B solar neutrino flux predicted by the standard solar model (SSM) is consistent within the theoretical and experimental uncertainties with that observed at Kamiokande. The Gallium and Chlorine solar neutrino experiments, however, seem to imply that the $^7$Be solar neutrino flux is strongly suppressed compared with that predicted by the SSM. If the $

Alexandre Kabanov

Each finite dimensional irreducible rational representation V of the symplectic group Sp_{2g} determines a generically defined local system \V over the moduli space M_g of genus g smooth projective curves. We study H^2(M_g;\V) and the mixed Hodge structure on it. Specifically, we prove that if g>5, then the natural map IH^2(MS_g;\V)-->H^2(M_g;\V) is an isomo

Rinat Kedem

We compute the R-matrix which intertwines two dimensional evaluation representations with Drinfeld comultiplication for U_q(\widehat{sl}_2). This R-matrix contains terms proportional to the delta-function. We construct the algebra A(R) generated by the elements of the matrices L^\pm(z) with relations determined by R. In the category of highest weight represe

Ezra Getzler

Given a mixed Hodge module E on a scheme X over the complex numbers, and a quasi-projective morphism f:X->S, we construct in this paper a natural resolution of the nth exterior tensor power of E restricted to the nth configuration space of f. The construction is reminiscent of techniques from the theory of hyperplane arrangements, and relies on Arnold&#39;s

Alon E. Faraggi

Discrete and global symmetries play an essential role in many extensions of the Standard Model, for example, to preserve the proton lifetime, to prevent flavor changing neutral currents, etc. An important question is how can such symmetries survive in a theory of quantum gravity, like superstring theory. In a specific string model I illustrate how local disc

Taekoon Lee

Higher order renormalons beyond the chain of one-loop bubbles are discussed. A perturbation method for the infrared renormalon residue is found. The large order behavior of the current-current correlation function due to the first infrared renormalon is determined in both QED and QCD to the first three orders.

E. Gedalin, A. Moalem, L. Razdolskaja

The total cross section for the pp to pp $π^0$ reaction at energies close to threshold is calculated in a covariant one-boson-exchange model. The amplitudes for the elementary BN to N$π^0$ processes are taken to be the sum of s, u and t pole terms. The main contributions to the primary productionamplitude is due to a sigma meson exchange. Both the scale and

J. M. Borwein, D. M. Bradley, D. J. Broadhurst

Euler sums (also called Zagier sums) occur within the context of knot theory and quantum field theory. There are various conjectures related to these sums whose incompletion is a sign that both the mathematics and physics communities do not yet completely understand the field. Here, we assemble results for Euler/Zagier sums (also known as multidimensional ze

Olivier Piguet

Contents: Generalities, Chiral supermultiplets, Super Yang-Mills theory, Superspace Feynman graphs, Renormalization, Supercurrent, Finite theories.

M. Beneke, M. Kraemer

Transverse polarization of ${}^3 S_1$ charmonium states, produced directly in $p\bar{p}$ collisions at asymptotically large transverse momentum p_t, has emerged as the most prominent test of color octet contributions and spin symmetry in quarkonium production. We present predictions for the polar angle distribution at moderate values of p_t \sim 4 - 20 GeV,

Tomas Blazek, Marcela Carena, Stuart Raby, Carlos E. M. Wagner

We present the details of a global $χ^2$ analysis of electroweak data, including fermion masses and mixing angles, in SO(10) SUSY GUTs. Just as precision electroweak data is used to test the Standard Model, the well determined Standard Model parameters are the precision electroweak data for testing theories beyond the Standard Model. In this paper we use the

Chen Zeng, D. J. J. Farnell, R. F. Bishop

We illustrate how the systematic inclusion of multi-spin correlations of the quantum spin-lattice systems can be efficiently implemented within the framework of the coupled-cluster method by examining the ground-state properties of both the square-lattice and the frustrated triangular-lattice quantum antiferromagnets. Various physical quantities including th

E. M. Burbidge, G. Burbidge

It has been claimed that the megamaser observations of the nucleus of NGC 4258 show that a massive black hole is present in its center (Miyoshi et al. 1995, Greenhill et al. 1995). We show that the evidence of ejection of gas, radio plasma, and X-ray emitting QSOs from this nucleus all show that the ejection is coming from the center in a curving flow within

Shahin S. Agaev

The pion electromagnetic form factor F_π(Q^{2}) is calculated at the leading order of pQCD using the running coupling constant (α_{S}(Q^{2}(1-x)(1-y))) approach. The resummed expression for F_π(Q^{2}) is found. It is shown that the effect of the infrared renormalons can be taken into account by scale-setting procedure $α_{S}(Q^{2}) \rightarrow α_{S}(e^{f(Q^{

H van Elst, C Uggla, W Lesame, G Ellis

We revisit the issue of integrability conditions for the irrotational silent cosmological models. We formulate the problem both in 1+3 covariant and 1+3 orthonormal frame notation, and show there exists a series of constraint equations that need to be satisfied. These conditions hold identically for FLRW-linearised silent models, but not in the general exact

F. Bernardeau

The weak lensing effects are known to change only weakly the shape of the power spectrum of the Cosmic Microwave Background (CMB) temperature fluctuations. I show here that they nonetheless induce specific non-Gaussian effects that can be detectable with the four-point correlation function of the CMB anisotropies. The magnitude and geometrical dependences of

Srinath Cheluvaraja, H. S. Sharatchandra

We make a numerical study of the finite temperature properties of the SO(3) lattice gauge theory. As its symmetry properties are quite different from those of the SU(2) LGT, a different set of observables have to be considered in this model. We study several observables, such as, the plaquette square, the Z(2) monopole density, the fundamental and adjoint Wi

Hong-Chen Fu, Ryu Sasaki

The generally deformed oscillator (GDO) and its multiphoton realization as well as the coherent and squeezed vacuum states are studied. We discuss, in particular, the GDO depending on a complex parameter q (therefore we call it q-GDO) together with the finite dimensional cyclic representations. As a realistic physical system of GDO the isospectral oscillator

A. Aghamohammadi, A. Alimohammadi, M. Khorrami

Generalizing the concept of primary fields, we find a new representation of the Virasoro algebra, which we call it a pseudo-conformal representation. In special cases, this representation reduces to ordinary- or logarithmic-conformal field theory. There are, however, other cases in which the Green functions differ from those of ordinary- or logarithmic-confo

P. S. Howe, E. Sezgin

The equations of motion of the super five-brane in D=11 dimensions are derived using the formalism of superembeddings. The equations describe highly nonlinear self-interactions of a tensor multiplet in the six dimensional worlsurface, and they have manifest worldsurface local supersymmetry. The geometry of the target space corresponds to D=11 supergravity.

Gordon P. Ramsey, Mehrdad Goshtasbpour

We have extracted polarized nucleon distributions from recent data at CERN, SLAC and DESY. The flavor-dependent valence and sea quark spin distributions are determined for each experiment. The up and down distributions are comparable, but the strange sea contribution determined from different experiments do not agree, even including higher order corrections.

J. Blümlein, S. Riemersma, A. Vogt

The resummation of the $α\ln^2(z)$ non-singlet contributions is performed for initial state QED corrections. As examples, the effect of the resummation on neutral-current deep-inelastic scattering and the $e^+ e^- \rightarrow μ^+ μ^-$ scattering cross section near the $Z^0$-peak is investigated.