May 1999 arXiv papers — page 19

B. G. Sidharth

A recent model which gives the contribution of the earth's solid core to geo magnetism is seen to explain Jupiter's magnetism also.

Thomas Kwok-keung Au, Tom Yau-heng Wan

In this article, the formation of biconcave vesicle according to the minimization bending energy (Helfrich's model) is studied. We present that in order to have biconcave shape vesicle, there are necessary conditions on the parameters of the energy functional and there are implications on the geometric quantities of the vesicle. Furthermore, we also give

Kevin K. Lehmann, Jan A. Northby

This paper presents an analysis of the motion of an impurity ion in a nanometer scale $^4$He cluster. Due to induction forces, ions are strongly localized near the center of the cluster, with a root mean squared thermal displacements of only a few Å. The trapping potential is found to be nearly harmonic, with a frequency of 2.3(1.0) GHz for a positive (negat

J. I. Johansson, H. S. Sherif

Relativistic calculations of the induced proton polarization in quasifree electron scattering on $^{12}C$ are presented. Good agreement with the experimental data of Woo et al. is obtained. The relativistic calculations yield a somewhat better description of the data than the non-relativistic ones. Differences between the two approaches are more pronounced a

Markus H. Thoma, Stefan Leupold, Ulrich Mosel

Assuming that rho-mesons exist in a quark-gluon plasma close to the QCD phase transition, we calculate the dilepton production rate from quark-antiquark annihilation via a rho-meson state using Vector Meson Dominance. The result is compared to the rates from direct quark-antiquark annihilation and from pion annihilation. Furthermore we discuss the suppressio

P. Stassart, Fl. Stancu, J. -M. Richard

We explore the role of a scalar meson exchange interaction between quarks in a semirelativistic constituent quark model where the quarks are also subject to a linear confinement. We search for a variational solution and study how the spectrum evolves when the strength of the scalar meson exchange increases. Our results have good implications on the descripti

I. R. Afnan

To understand the difference between the value of the nn and Lambda-Lambda two-body matrix elements, we examine the role of the coupling between the Lambda-Lambda and Xi-N channels, first within the framework of SU(3), and second in the numerical results for the binding energy of Lambda-Lambda 6He. We find that it is essential to include the coupled channel

Oscar Bolina, J. Rodrigo Parreira

We derive a McBryan-Spencer bound to the correlation function of a one-dimensional array of quantum rotators in the Villain approximation of the cosine interaction. We obtain the partition function of the system in the gas representation and establish a lower bound on the external charge correlation function. We also discuss the possible existence of a Koste

Claude Sabbah

We identify the holomorphic de Rham complex of the minimal extension of a meromorphic vector bundle with connexion on a compact Riemann surface X with the L^2 complex relative to a suitable metric on the bundle and a complete metric on the punctured Riemann surface. Applying results of C. Simpson, we show the existence of a harmonic metric on this vector bun

Massimo Giulietti, Fernanda Pambianco, Fernando Torres, Emmanuela Ughi

An approach for the computation of upper bounds on the size of large complete arcs is presented. We obtain in particular geometrical properties of irreducible envelopes associated to a second largest complete arc provided that the order of the underlying field is large enough. We use Stoehr-Voloch's approach to the Hasse-Weil bound for rational points of

Werner Mueller, Katrin Wendland

Let (X,[ω]) be a compact Kaehler manifold with a fixed Kaehler class [ω]. Let K_ωbe the set of all Kaehler metrics on X whose Kaehler class equals [ω]. In this paper we investigate the critical points of the functional Q(g)= |v|_g T_0(X,g)^{1/2} for g \in K_ω, where v is a fixed nonzero vector of the determinant line λ(X) associated to H^*(X) and T_0(X,g) is

Viktor L. Ginzburg, Ely Kerman

The Hamiltonian flow of the standard metric Hamiltonian with respect to the twisted symplectic structure on the cotangent bundle describes the motion of a charged particle on the base. We prove that under certain natural hypotheses the number of periodic orbits on low energy levels for this flow is at least the sum of Betti numbers of the base. The problem i

Eric D'Hoker, Daniel Z. Freedman, Leonardo Rastelli

A new method is discussed which vastly simplifies one of the two integrals over AdS(d+1) required to compute exchange graphs for 4-point functions of scalars in the AdS/CFT correspondence. The explicit form of the bulk-to-bulk propagator is not required. Previous results for scalar, gauge boson and graviton exchange are reproduced, and new results are given

Paolo Budinich

Conformally compactified phase space is conceived as an automorphism space for the global action of the extended conformal group. Space time and momentum space appear then as conformally dual, that is conjugate with respect to conformal reflections. If now the former, as generally agreed, is appropriate for the description of classical mechanics in euclidean

Paul H. Frampton

It has been recently proposed to embed the standard model in a conformal gauge theory to resolve the hierarchy problem, and to avoid assuming either grand unification or low-energy supersymmetry. By model building based on string-field duality we show how to maintain the successful prediction of an electroweak mixing angle with $sin^2θ\simeq 0.231$ in confor

V. A. Kudryavtsev

New string dynamics is formulated on the basis of the extended set of supergauge constraints including not only supergauge Virasoro conditions but also nilpotent supercurrent constraints . This approach arises from a natural generalization of the classical operator many-string vertices. The formulation of this model leads to three two-dimensional surfaces fo

G. V. Vlasov

Instead of the infinitesimal extrinsic and intrinsic perturbations on strings, considered so far, we discuss the evolution and propagation of finite-amplitude perturbations. Those intrinsic perturbations may result in appearance of stable discontinuities similar to the shock waves.

Mihir P. Worah

We discuss the sensitivity of the CP violating measurements at the upcoming B factories to the presence of physics beyond the Standard Model. We review the three manifestations of CP violation possible in the B meson system. We give examples of decay modes for each of these which are sensitive to new physics, are experimentally feasible, and theoretically cl

A. Belyaev, M. Drees, O. J. P. Eboli, J. K. Mizukoshi

We study the pair production of neutral Higgs bosons through gluon fusion at hadron colliders in the framework of the Minimal Supersymmetric Standard Model. We present analytical expressions for the relevant amplitudes, including both quark and squark loop contributions, and allowing for mixing between the superpartners of left- and right-handed quarks. Squa

T. E. Clark, S. T. Love

Simultaneous nonlinear realizations of supersymmetry and softly broken scale and chiral symmetries are investigated. To guarantee Nambu-Goldstone realizations of the symmetries, the Goldstino decay constant is forced to vary as the explicit soft scale and chiral symmetry breaking parameters. Consequently, it must vanish in the chiral limit and the simultaneo

A. V. Belitsky, D. Muller

We give an outline of a formalism for the solution of the evolution equations for off-forward parton distributions in leading and next-to-leading orders based on partial conformal wave expansion and orthogonal polynomials reconstruction.

Teiji Kunihiro

We first discuss the theoretical and phenomenological significance of the sigma meson ($σ$) in QCD. It is indicated that if the collective modes with the mass 500-600 MeV exists in the $I=J=0$ channel, various empirical facts in hadron physics can be naturally accounted for, which otherwise would remain mysterious. We propose several experiments to produce a

Muneyuki Ishida, Shin Ishida, Taku Ishida, Kunio Takamatsu

Recently we obtained the evidence for the existence of sigma(600) meson, which had been sought but missing for a long time, by reanalyzing the I=0 S-wave pi pi scattering phase shift. The sigma-existence was also suggested through the analyses of pi pi production processes, pp central collision pp to pp pi^0 pi^0 and J/psi to omega pi pi decay. The observed

Shin Ishida

The light sigma-particle is, regardless of the strong criticism, reviving recently due to the works done from various sides. I review essential points of the controversies (especially related to our works) and of their answer: Conventionally a large concentration of the iso-scalar S-wave 2 pi events below 1 GeV (being, correctly, due to the sigma-production)

Muneyuki Ishida

Recently, by reanalyzing the phase shift data of I=0 pipi$ and of I=1/2 Kpi scatterings, we showed the evidences for existence of light scalar mesons, sigma(600) and kappa(900), respectively, which had been sought but missing for a long time. The sigma(600) and kappa(900) together with the established resonances, a_0(980) and f_0(980), are shown to be consis

Shin Ishida, Muneyuki Ishida

The level classification of quark-antiquark systems is generally made by the LS-coupling scheme, resorting to the non-relativistic quark model. However, it has been well known that the pi-meson with the (L,S)=(0,0) shows also the properties as a Nambu-Goldstone boson in the case of spontaneous breaking of a relativistic symmetry, the chiral symmetry. In this

Wick C. Haxton, Barry R. Holstein

The basic concepts of neutrino physics are presented at a level appropriate for integration into elementary courses on quantum mechanics and/or modern physics.

M. Hayakawa

Here we invoke the current and future perspective on muon $g-2$ measurement when asking what the muon $g-2$ could tell about the underlying structure concerning with the hierarchy problem. Here we take up two such models, the presence of which turns out to alter the standard model prediction for muon $g-2$ significantly: one is TeV scale gravity scenario, th

G. V. Vlasov

We consider the discontinuities in a two-constituent relativistic superfluid. In the acoustic limit they degenerate into the first and second sound which are independent up to the second-order linear approximation. Inclusion of the quadratic deviations relates to the small-amplitude shock. Particularly we consider a plane shock at low temperature when the ph

Robert G. Edwards, Urs M. Heller

We investigate the finite temperature behavior of nonperturbatively improved clover fermions on lattices with temporal extent N_t=4 and 6. Unfortunately in the gauge coupling range, where the clover coefficient has been determined nonperturbatively, the finite temperature crossover/transition occurs at heavy pseudoscalar masses and large pseudoscalar to vect

A. Di Giacomo, D. Martelli, G. Paffuti

The Heisenberg model in 3d is studied from a dual point of view. It is shown that it can have vortex configurations, carrying a conserved charge(U(1) symmetry). Vortices condens in the disordered phase. A disorder parameter $\leftangleμ\rightangle$ is defined dual to the magnetization $\leftangle\vec n\rightangle$, which signals condensation of vortices, i.e

Giorgio Gratta

In this paper I give an overview of the status of neutrino oscillation experiments performed using nuclear reactors as sources of neutrinos. I review the present generation of experiments (Chooz and Palo Verde) with baselines of about 1 km as well as the next generation that will search for oscillations with a baseline of about 100 km. While the present dete

G. Gratta, Y. F. Wang

We discuss an alternative approach to the detection of solar neutrinos using a coarsely segmented detector based on inverse-beta decay onto $^{160}$Gd or $^{176}$Yb. While it is know that similar approaches, already discussed in the literature, can in principle provide low-threshold, real-time energy spectroscopy with intrinsic background rejection features,

Roberto Scipioni

We extend the recently proved relation between certain models of Non-Riemannian gravitation and Einstein- Proca-Weyl theories to a class of Scalar gravity theories. This is used to present a Black-Hole Dilaton solution with non-Riemannian connection.

S. Deser, J. S. Franklin, D. Seminara

Motivated by recent work involving the graviton-graviton tree scattering amplitude, and its twin descriptions as the square of the Bel-Robinson tensor, $B_{\m\n\a\b}$, and as the "current-current interaction" square of gravitational energy pseudo-tensors $t_{\a\b}$,we find an exact tensor-square root equality $B_{\mn\a\b} = \pa^2_\mn t_{\a\b}$, for a

Bernard F. Schutz, M. Alessandra Papa

We describe a hierarchical, highly parallel computer algorithm to perform searches for unknown sources of continuous gravitational waves -- spinning neutron stars in the Galaxy -- over wide areas of the sky and wide frequency bandwidths. We optimize the algorithm for an observing period of 4 months and an available computing power of 20 Gflops, in a search f

Ll. Bel

We present an example where a justified modification of the law of propagation of light in a Robertson-Walker model of the universe leads to an identification of H_0 and q_0 different from that corresponding to the usual law of propagation along null geodesics. We conclude from this example that observed values which we would associate with the values of H_0

Winfried Zimdahl, Alexander B. Balakin

We show that a relativistic gas may be at ``global&#39;&#39; equilibrium in the expanding universe for any equation of state $0 < p \leq ρ/3$, provided that the gas particles move under the influence of a self-interacting, effective one-particle force in between elastic binary collisions. In the force-free limit we recover the equilibrium conditions for ultr

S. O. Valenzuela, G. A. Jorge, E. Rodriguez

Repulsive and attractive forces are both possible between a superconducting sample and a permanent magnet, and they can give place to magnetic levitation or free-suspension phenomena, respectively. We show experiments to quantify this magnetic interaction which represents a promising field regarding to short-term technological applications of high temperatur

Susanna C. Manrubia, Alexander S. Mikhailov

We introduce and study systems of randomly coupled maps (RCM) where the relevant parameter is the degree of connectivity in the system. Global (almost-) synchronized states are found (equivalent to the synchronization observed in globally coupled maps) until a certain critical threshold for the connectivity is reached. We further show that not only the avera

D. Quesada, A. Rubio-Ponce, R. Pena, R. Baquero

An analysis of the different approaches used within the van Hove BCS model for the high temperature superconductors has been done. How far the employment of an asymptotic expression for the density of states underestimates the thermodynamic parameters, as for example, the critical temperature, the gap at zero temperature, and the known universal ratios of th

J. Vidal, D. Mouhanna, T. Giamarchi

We study analytically one-dimensional interacting spinless fermions in a Fibonacci potential. We show that the effects of the quasiperiodic modulation are intermediate between those of a commensurate potential and a disordered one. The system exhibits a metal-insulator transition whose position depends both on the strength of the correlations and on the posi

J. Myslivecek, T. Jarolimek, P. Smilauer, B. Voigtlaender

Surface reconstructions can drastically modify growth kinetics during initial stages of epitaxial growth as well as during the process of surface equilibration after termination of growth. We investigate the effect of activation barriers hindering attachment of material to existing islands on the density and size distribution of islands in a model of homoepi

R. Bulla, M. Potthoff

The Mott-Hubbard metal-insulator transition is studied within a simplified version of the Dynamical Mean-Field Theory (DMFT) in which the coupling between the impurity level and the conduction band is approximated by a single pole at the Fermi energy. In this approach, the DMFT equations are linearized, and the value for the critical Coulomb repulsion U_{\rm

Maria de Sousa Vieira

We study statistical properties of DNA chains of thirteen microbial complete genomes. We find that the power spectrum of several of the sequences studied flattens off in the low frequency limit. This implies that the correlation length in those sequences is much smaller than the entire DNA chain. Consequently, in contradiction with previous studies, we show

Marcio Argollo de Menezes, Cristian F. Moukarzel

We study directed rigidity percolation (equivalent to directed bootstrap percolation) on three different lattices: square, triangular, and augmented triangular. The first two of these display a first-order transition at p=1, while the augmented triangular lattice shows a continuous transition at a non-trivial p_c. On the augmented triangular lattice we find,

R. Maezono, S. Murakami, N. Nagaosa, S. Ishihara

We study the manganese oxides from the viewpoint of the strongly correlated doped Mott insulator. The magnetic ordering and the charge transport are governed by the orbital degrees of freedom, and their dimensionality is controlled by the anisotropic transfer integrals between the $e_g$ orbitals. As x increases the magnetic structure is predicted to change a

J. -B. Fournier, P. Galatola

We introduce a coarse-grained description of the surface energy of a nematic liquid crystal. The thermal fluctuations of the nematic director close to the surface renormalize at macroscopic scales the bare surface potential in a temperature-dependent way. The angular dependence of the renormalized potential is dramatically smoothed, thus explaining the succe

B. Biswal, R. Hilfer

We compare the quantitative microstructural properties of Berea Sandstone with stochastic reconstructions of the same sandstone. The comparison is based on local porosity theory. The reconstructions employ Fourier space filtering of Gaussian random fields and match the average porosity and two-point correlation function of the experimental model. Connectivit

Kouji Yasui, Takafumi Kita

We study quasiparticles of d-wave superconductors in the vortex lattice by self-consistently solving the Bogoliubov-de Gennes equations. It is found for a pure $d_{x^2-y^2}$ state that: (i) low-energy quasiparticle bands in the magnetic Brillouin zone have rather large dispersion even in low magnetic fields, indicating absense of bound states for an isolated

R. V. Kulkarni, E. Almaas, D. Stroud

We study the dynamics of the Bak-Sneppen model on small-world networks. For each site in the network, we define a ``connectance,&#39;&#39; which measures the distance to all other sites. We find radically different patterns of activity for different sites, depending on their connectance and also on the topology of the network. For a given network, the site w

Daniel J. Flees, J. E. Lukens, Siyuan Han

The reduced switching current of an excited energy-band in a Bloch transistor can be used to detect microwave-induced interband transitions. Spectroscopic measurements of the band-gap are performed by mapping the frequency dependence of the excitation threshold where the microwave photon energy and band-gap are equal. This excitation threshold also provides

Thomas Papenbrock, Tomaz Prosen

We consider a billiard model of a self-bound, interacting three-body system in two spatial dimensions. Numerical studies show that the classical dynamics is chaotic. The corresponding quantum system displays spectral fluctuations that exhibit small deviations from random matrix theory predictions. These can be understood in terms of scarring caused by a 1-pa

Alberto Castro-Tirado, Soeren Brandt, Niels Lund, Rashid Sunyaev

During 1990-92, the WATCH all-sky X-ray monitor on Granat discovered six short-duration X-ray transients. In this paper we discuss their possible relationship to peculiar stars. Only one of the fast (few hours) X-ray transients (GRS 1100-771) might be tentatively ascribed to a superflare arising from a young stellar object in the Chamaeleon I star-forming cl

Luis C. Ho, Schuyler D. Van Dyk, Guy G. Pooley, Richard A. Sramek

The low-luminosity active galactic nucleus of M81 has been monitored at centimeter wavelengths since early 1993 as a by-product of radio programs to study the radio emission from Supernova 1993J. The extensive data sets reveal that the nucleus experienced several radio outbursts during the monitoring period. At 2 and 3.6 cm, the main outburst occurred roughl

R. F. Peletier, J. H. Knapen, I. Shlosman, D. Perez-Ramirez

We present new high-resolution near-infrared observations in the J,H and K bands, obtained to study the properties of Seyfert host galaxies. The dataset consists of images in the three bands of practically the entire CfA sample of Seyfert galaxies, and K-band images of a control sample of non-active, `normal', galaxies, matched to the Seyfert sample in the d

M. J. Reid, A. C. S. Readhead, R. C. Vermeulen, R. N. Treuhaft

We observed Sgr A* and two extragalactic radio sources nearby in angle with the VLBA over a period of two years and measured relative positions with an accuracy approaching 0.1 mas. The apparent proper motion of Sgr A* relative to J1745-283 is 5.90 +/- 0.4 mas/yr, almost entirely in the plane of the Galaxy. The effects of the orbit of the Sun around the Gala

M. J. Lehner, K. Griest, C. J. Martoff, G. E. Masek

A low pressure time projection chamber for the detection of WIMPs is discussed. Discrimination against Compton electron background in such a device should be very good, and directional information about the recoil atoms would be obtainable. If a full 3-D reconstruction of the recoil tracks can be achieved, Monte Carlo studies indicate that a WIMP signal coul

Rosa Murphy Williams, You-Hua Chu, John R. Dickel, Robert Petre

We have used archival ROSAT data to present X-ray images of thirty-one supernova remnants (SNRs) in the Large Magellanic Cloud (LMC). We have classified these remnants according to their X-ray morphologies, into the categories of Shell-Type, Diffuse Face, Centrally Brightened, Point-Source Dominated, and Irregular. We suggest possible causes of the X-ray emi

Remo Ruffini

Recent works on the Dyadosphere are reviewed.

Remo Ruffini

Works on the Dyadosphere are reviewed.

S. B. Popov, M. E. Prokhorov, V. M. Lipunov

This paper is a continuation and development of our previous articles (Popov et al., 1997, 1998). We use ``Scenario Machine&#39;&#39; (Lipunov et al., 1996b) -- the population synthesis simulator (for single binary systems calculations the program is available in WWW at: http://xray.sai.msu.su/sciwork/scenario.html (Nazin et al., 1998) -- to calculate evolut

J. G. Kirk, P. Duffy

Observations of both gamma-ray burst sources and certain classes of active galaxy indicate the presence of relativistic shock waves and require the production of high energy particles to explain their emission. In this paper we review the basic theory of shock waves in relativistic hydrodynamics and magneto-hydrodynamics, emphasising the astrophysically inte

F. Meyer, E. Meyer-Hofmeister

We suggest, that the magnetic field of the white dwarf in AM Her systems loses coupling to the secondary star when the latter becomes non-magnetic at the transition from a late main sequence star to a cool degenerate brown dwarf. This leads to spin-up of the primary white dwarf. After synchronous rotation is lost the systems do not appear as AM Her stars any

Wyn Evans, Serge Tabachnik

The recent years have witnessed a carnival of discoveries in the Outer Solar System. Here we provide evidence from numerical simulations of orbital stability to suggest the possible existence of two long lived belts of primordial planetesimals in the Solar System. The first is the domain of the Vulcanoids (between 0.09 - 0.21 AU) between the Sun and Mercury,

L. K. Hunt, M. A. Malkan, B. Rush, M. D. Bicay

We present 263 optical and near-infrared (NIR) images for 42 Seyfert 1s and 48 Seyfert 2s, selected from the Extended 12-micron Galaxy Sample. Elliptically-averaged profiles are derived from the images, and isophotal radii and magnitudes are calculated from these. We also report virtual aperture photometry, that judging from comparison with previous work, is

A. Olech, P. R. Wozniak, C. Alard, J. Kaluzny

We present $V$-band light curves of 61 variables from the core of the globular cluster M5 obtained using a newly developed image subtraction method (ISM). Four of these variables were previously unknown. Only 26 variables were found in the same field using photometry obtained with DoPHOT software. Fourier parameters of the ISM light curves have relative erro

G. Moriondo, R. Giovanelli, M. Haynes

We determine the parameters of scaling relations analogous to the Fundamental Plane of elliptical galaxies for the bulges and disks of a sample of 40 spiral galaxies. To this end we derive structural parameters (scalelengths and surface brightnesses) from near infrared H band images, and kinematical parameters (rotational velocities) from optical rotation cu

G. Moriondo, C. Baffa, S. Casertano, G. Chincarini

We present near-infrared, H-band (1.65 um), surface photometry of 174 spiral galaxies in the area of the Pisces-Perseus supercluster. The images, acquired with the ARNICA camera mounted on various telescopes, are used to derive radial profiles of surface brightness, ellipticities, and position angles, together with global parameters such as H-band magnitudes

Jeong-Eun Lee, Kee-Tae Kim, Bon-Chul Koo

We have carried out high-resolution observations along one-dimensional cuts through the three Galactic supershells GS 064-01-97, GS 090-28-17, and GS 174+02-64 in the HI 21 cm and CO J=1-0 lines. By comparing the HI data with IRAS data, we have derived the distributions of the I_100 and tau_100 excesses, which are, respectively, the 100 mum intensity and 100

Myung Gyoon Lee, Yong-Ik Byun

We present deep BVRI CCD photometry of the stars in the dwarf irregular galaxy UKS 2323-326 in the Sculptor Group. The color-magnitude diagrams of the measured stars in UKS 2323-326 show a blue plume which consists mostly of young stellar populations, and a well-defined red giant branch (RGB). The tip of the RGB is found to be at I_TRGB = 22.65 +/- 0.10 mag.

M. Asplund, AA. Nordlund, R. Trampedach, R. F. Stein

Realistic 3-dimensional (3D), radiative hydrodynamical surface convection simulations of the metal-poor halo stars HD 140283 and HD 84937 have been performed. Due to the dominance of adiabatic cooling over radiative heating very low atmospheric temperatures are encountered. The lack of spectral lines in these metal-poor stars thus causes much steeper tempera

Simon Johnston, David Galloway

Using the standard equation for the slowdown of a neutron star, we derive a formula for the braking index via integration rather than the conventional differentiation. The new formula negates the need to measure the second time derivative of the rotation frequency. We show that the method gives similar braking indices for PSR B1509-58 and the Crab pulsar to

Takuji Tsujimoto, Toshikazu Shigeyama, Yuzuru Yoshii

A model for Galactic chemical evolution, driven by supernova-induced star formation, is formulated and used to examine the nature of the Galactic halo at early epochs. In this model, new stars are formed following each supernova event, thus their abundance pattern is determined by the combination of heavy elements ejected from the supernova itself and those

Y. Sofue, Y. Tutui, M. Honma, A. Tomita

We present high-resolution central-to-outer rotation curves for Sb, SBb, Sc, and SBc galaxies. We discuss their general characteristics, particularly their central behavior, as well as dependencies on morphological types, activity, and peculiarity. The rotation curves generally show a steep nuclear rise, and high-velocity central rotation, followed by a broa

A. Hopkins, J. Afonso, L. Cram, B. Mobasher

We present a deep 1.4 GHz survey made with the Australia Telescope Compact Array (ATCA), having a background RMS of 9 microJy near the image phase centre, up to 25 microJy at the edge of a 50&#39; field of view. Over 770 radio sources brighter than 45 microJy have been catalogued in the field. The differential source counts in the deep field provide tentativ

T. G. Wang, J. X. Wang, W. Brinkmann, M. Matsuoka

Recently, convincing evidence was found for extremely large X-ray absorption by column densities $> 10^{23} cm^{-2}$ in broad absorption line quasars. One consequence of this is that any soft X-ray emission from these QSOs would be the scattered light or leaked light from partially covering absorbing material. A detection of the unabsorbed soft X-ray and abs

T. Di Matteo, E. Quataert, S. W. Allen, R. Narayan

The discovery of hard, power-law X-ray emission from a sample of six nearby elliptical galaxies, including the dominant galaxies of the Virgo,Fornax and Centaurus clusters (M87, NGC 1399 and NGC 4696, respectively), and NGC 4472, 4636 and 4649 in the Virgo cluster, has important implications for the study of quiescent supermassive black holes. We describe ho

Tyler J. Jarvis, Takashi Kimura, Arkady Vaintrob

We prove the genus zero part of the generalized Witten conjecture relating moduli spaces of spin curves to Gelfand-Dickey hierarchies. That is, we show that intersection numbers on the moduli space of stable r-spin curves assemble into a generating function which yields a solution of the semiclassical limit of the KdV_r equations. We formulate axioms for a c

Sumit R. Das

If the AdS/CFT correspondence is valid in the Coulomb branch, the potential between waves on a pair of test branes in the bulk should be reproduced by the relevant Yang-Mills theory effective action on the boundary. Earlier work has provided evidence for this in the case of constant gauge field brane waves. In this paper we provide concrete evidence for an e

I. Bediaga, E. M. F. Curado, J. M. de Miranda

We show that the inclusion of long distance effect, expected in strong interactions, through a nonextensive thermodynamical approach is able to explain the experimental distribution of the transverse momentum of the hadrons with respect to the jet axis ($p_{t}$) $e^+ e^- \to hadron$ reaction. The observed deviation from the exponential behavior, predicted by

Frank Varosi, Eli Dwek

We present analytical approximations for calculating the scattering, absorption and escape of nonionizing photons from a spherically symmetric two-phase clumpy medium, with either a central point source of isotropic radiation, a uniform distribution of isotropic emitters, or uniformly illuminated by external sources. The analytical approximations are based o

PACS Collaboration, M. Okamoto, A. Ali Khan, S. Aoki

A lattice study of the equation of state for pure SU(3) gauge theory using a renormalization-group (RG) improved action is presented. The energy density and pressure are calculated on a $16^3\times 4$ and a $32^3\times 8$ lattice employing the integral method. Extrapolating the results to the continuum limit, we find the energy density and pressure to be in

M. Laine, O. Philipsen

According to a proposal by Arnold and Yaffe, the non-perturbative g^2T-contribution to the Debye mass in the deconfined QCD plasma phase can be determined from a single Wilson line operator in the three-dimensional pure SU(3) gauge theory. We extend a previous SU(2) measurement of this quantity to the physical SU(3) case. We find a numerical coefficient whic

Zurab Kakushadze

We consider non-perturbative six dimensional N=1 space-time supersymmetric orientifolds of Type IIB on K3 with non-trivial NS-NS B-flux. All of these models are non-perturbative in both orientifold and heterotic pictures. Thus, some states in such compactifications arise in ``twisted&#39;&#39; open string sectors which lack world-sheet description in terms o

Alexei Borodin, Andrei Okounkov, Grigori Olshanski

We consider the asymptotics of the Plancherel measures on partitions of $n$ as $n$ goes to infinity. We prove that the local structure of a Plancherel typical partition (which we identify with a Young diagram) in the middle of the limit shape converges to a determinantal point process with the discrete sine kernel. On the edges of the limit shape, we prove t

D. A. Garanin, K. Kladko, P. Fulde

We propose a method for obtaining effective classical Hamiltonians \cal H for many-body quantum spin systems with large spins. This method uses the coherent-state representation of the partition function Z and the cumulant expansion in powers of 1/S. For the quantum Hamiltonian \hat H of a Heisenberg form, the 1/S corrections in \cal H have a non-Heisenberg

Claudio Ciofi degli Atti, Geoffrey B. West

Some systematic general features of y-scaling structure functions, which are essentially independent of detailed dynamics, are pointed out. Their physical interpretation in terms of general characteristics, such as a mean field description and nucleon-nucleon correlations, is given and their relationship to the momentum distributions illustrated. A new relat

Paolo Tozzi, Colin Norman

The properties of X-ray clusters of galaxies can be well understood in terms of a competition between shock heating and adiabatic compression. Strong shocks are expected to be important for massive clusters, while adiabatic compression is dominant for small clusters and groups. The scale of the shock/adiabatic transition is marked by a change of slope of the

Yehuda Eisenberg

We report the latest results of the ZEUS collaboration on the photoproduction of D* mesons in a low W range. Differential cross sections as function of pt(D*) and eta(D*) are measured and compared with several recent NLO pQCD calculations. The differential cross-sections in a restricted kinematical region are higher than the NLO calculations, in particular i

Paul Langacker, Nir Polonsky, Jing Wang

In the gauge-mediation framework the soft supersymmetry breaking mass parameters of the supersymmetric standard model are induced by the gauge interactions of some messenger fields. The parameters exhibit flavor universality which is dictated by the gauge interactions and which efficiently eliminates new dangerous contributions to flavor changing neutral cur

P. O. Fedichev, A. E. Muryshev, G. V. Shlyapnikov

We develop a theory of dissipative dynamics of a kink state in a finite-temperature Bose-condensed gas. We find that due to the interaction with the thermal cloud the kink state accelerates towards the velocity of sound and continuously transforms to the ground-state condensate. We calculate the life-time of a kink state in a trapped gas and discuss possible

Richard D. Saam

A numerical and dimensional correlation supported by reported literature experimental evidence (Homes, Harshmann along with Voyager, EGRET, FERMI, WMAP, Planck and other space platforms) is presented which indicates that superconductivity is congruent with Charge Conjugation, Parity Change and TimeReversal (CPT) theorem and scalable with Friedmann Lemaire Ro

T. Calarco, E. A. Hinds, D. Jaksch, J. Schmiedmayer

We theoretically study specific schemes for performing a fundamental two-qubit quantum gate via controlled atomic collisions by switching microscopic potentials. In particular we calculate the fidelity of a gate operation for a configuration where a potential barrier between two atoms is instantaneously removed and restored after a certain time. Possible imp

Augusto Smerzi, Srikanth Raghavan

We study the quantum corrections to the Gross-Pitaevskii equation for two weakly linked Bose-Einstein condensates. The goals are: 1) to investigate dynamical regimes at the borderline between the classical and quantum behaviour of the bosonic field; 2) to search for new macroscopic quantum coherence phenomena not observable with other superfluid/superconduct

J. Fleischer, M. Yu. Kalmykov, A. V. Kotikov

Analytic results for the complete set of two-loop self-energy master integrals on shell with one mass are calculated.

H. Appelshauser, NA49 Collaboration

The two-proton correlation function at midrapidity from Pb+Pb central collisions at 158 AGeV has been measured by the NA49 experiment. The results are compared to model predictions from static thermal Gaussian proton source distributions and transport models RQMD and VENUS. An effective proton source size is determined by minimizing CHI-square/ndf between th

N. D. Lambert, P. C. West

We give a basic account of supersymmetric open strings and D-branes using the Green-Schwarz formalism, obtaining a manifestly spacetime supersymmetric description of their spectrum. In addition we discuss a mechanism whereby some of the D-brane states are projected out and which can lead to chiral quantum field theories on the brane.

M. A. Vazquez-Mozo

The thermodynamics of supersymmetric Yang-Mills theories is studied by computing the two-loop correction to the canonical free energy and to the equation of state for theories with 16, 8 and 4 supercharges in any dimension $4\leq d\leq 10$, and in two dimensions at finite volume. In the four-dimensional case we also evaluate the first non-analytic contributi

N. D. Lambert, P. C. West

We calculate from M-theory the two-dimensional low energy effective dynamics of various brane configurations. In the first part we study configurations that have a dual description in type IIA string theory as two-dimensional (4,0) Yang-Mills theories with gauge group SU(N_1)xSU(N_2) and chiral fermions in the bi-fundamental representation. In the second par