July 2000 arXiv papers — page 4

Franz W. Kamber, Peter W. Michor

For a vector field $X$ on a smooth manifold $M$ there exists a smooth but not necessarily Hausdorff manifold $M_\Bbb R$ and a complete vector field $X_\Bbb R$ on it which is the universal completion of $(M,X)$.

Paul Redparth

We describe the general qualitative behaviour of the resolvent norm for a very wide class of non-self-adjoint Schroedinger operators in the semi-classical regime, as the spectral parameter varies over the complex plane.

I. Shimada, D. -Q. Zhang

We present a complete list of extremal elliptic K3 surfaces. There are altogether 325 of them. The first 112 coincides with Miranda-Persson's list for semi-stable ones. The data include the transcendental lattice which determines uniquely the K3 surface by a result of Shioda and Inose, the singular fibre type and the Mordell Weil group. As an application

Rajesh Gopakumar, Shiraz Minwalla, Andrew Strominger

It has recently been argued that D-branes in bosonic string theory can be described as noncommutative solitons, outside whose core the tachyon is condensed to its ground state. We conjecture that, in addition, the local U(1) gauge symmetry is restored to a $U(\infty)$ symmetry in the vacuum outside this core. We present new solutions obeying this boundary co

Carlos Castro

A straightforward explanation of the Young's two-slit experiment of a quantum particle is obtained within the framework of the Noncommutative Geometric associated with El Naschie's Cantorian-Fractal transfinite Spacetime continuum.

S. P. de Alwis, Nikolaos Irges

Brane world scenarios offer a way of setting the cosmological constant to zero after supersymmetry breaking provided there is a sufficient number of adjustable integration constants/parameters. In the case of the Horava-Witten theory compactified on a Calabi-Yau threefold, we argue that it is difficult to find enough freedom to get a zero (or small) cosmolog

F. Bastianelli, G. Cuoghi, L. Nocetti

Conformally invariant quantum field theories develop trace anomalies when defined on curved backgrounds. We study again the problem of identifying all possible trace anomalies in d=6 by studying the consistency conditions to derive their 10 independent solutions. It is known that only 4 of these solutions represent true anomalies, classified as one type A an

P. Furlan, V. B. Petkova

The construction of the fusion ring of a quasi-rational CFT based on $\hat{sl}(3)_k$ at generic level $k\not \in {\Bbb Q}$ is reviewed. It is a commutative ring generated by formal characters, elements in the group ring ${\Bbb Z}[\tilde{W}]$ of the extended affine Weyl group $\tilde{W}$ of $\hat{sl}(3)_k$. Some partial results towards the $\hat{sl}(4)_k$ gen

M. Ghilardi, E. Guadagnini

We report the statistical properties of classical particles in (2+1) gravity as resulting from numerical simulations. Only particle momenta have been taken into account. In the range of total momentum where thermal equilibrium is reached, the distribution function and the corresponding Boltzmann entropy are computed. In the presence of large gravity effects,

Seok-In Hong, John B. Kogut

We study the symmetry behavior of the Gross-Neveu model in three and two dimensions with random chemical potential. This is equivalent to a four-fermion model with charge conjugation symmetry as well as Z_2 chiral symmetry. At high temperature the Z_2 chiral symmetry is always restored. In three dimensions the initially broken charge conjugation symmetry is

R. N. Mohapatra

Recent developments in supersymmetric unified theories are reviewed, with particular emphasis on supersymmetric grand unification and a brief discussion of recent ideas about extra dimensions.

A. Ljubicic, D. Kekez

We propose a novel experimental method to produce and detect weakly interacting light vector bosons using coherent processes in refractive media. A light vector boson would be produced by a laser photon scattered at a plane interface between two media of different dielectric properties and will be converted back to photon in the similar scattering process. T

M. Suzuki

Extending the dynamics underlying the factorization calculation of two-body decays, we propose simple selection rules for nonresonant three-body B decays. We predict, for instance, that in the Dalitz plot of B^0-->D^0-bar\pi^+\pi^-, practically no events should be found in the corner of E(\pi^+) < \Lambda_{QCD} as compared with the corner of E(\pi^-) < \Lamb

Ernest Ma, Martti Raidal, Utpal Sarkar

The mass of the axion and its decay rate are known to depend only on the scale of Peccei-Quinn symmetry breaking, which is constrained by astrophysics and cosmology to be between $10^9$ and $10^{12}$ GeV. We propose a new mechanism such that this effective scale is preserved and yet the fundamental breaking scale of $U(1)_{PQ}$ is very small (a kind of inver

C. E. Wolfe, K. Maltman

The strong isospin-breaking correction, Omega_{st}, which appears in estimates of the Standard Model value for the direct CP-violating ratio epsilon&#39;/epsilon, is evaluated to next-to-leading order (NLO) in the chiral expansion using Chiral Perturbation Theory. The relevant linear combinations of the unknown NLO CP-odd weak low-energy constants (LEC&#39;s

Stefan Weinzierl, Oleg Yakovlev

We suggest a new approach for calculating heavy-to-light form factors. The method is based on light cone sum rules (LCSR) and covers the whole kinematical range of momentum transfer. The derivation of the new sum rule uses a suitable combination of double and single dispersion integrals. As an example we give numerical results for the form factor f^+ for the

Christer Friberg, Torbjörn Sjöstrand

A model for total cross sections with virtual photons is presented. In particular gamma*-p and gamma*-gamma* cross sections are considered. Our approach extends on a model for photoproduction, where the total cross section is subdivided into three distinct event classes: direct, VMD and anomalous. With increasing photon virtuality, the latter two decrease in

A. J. Buras, P. Gambino, M. Gorbahn, S. Jager

We analyze the CP violating ratio epsilon&#39;/epsilon and rare K and B decays in the MSSM with minimal flavour and CP violation, including NLO QCD corrections and imposing constraints on the supersymmetric parameters coming from epsilon, B_{d,s}^0-\bar B_{d,s}^0 mixings, B to X_s gamma, Delta rho in the electroweak precision studies and from the lower bound

V. S. Fadin, R. Fiore, M. I. Kotsky

Recently the non-forward BFKL kernel for interaction of two Reggeized gluons in the antisymmetric colour octet state in the $t$-channel was obtained in the next-to-leading order. It gives the possibility to check in this order the bootstrap condition for this kernel, appearing as the requirement of the compatibility of gluon Reggeization with the $s$-channel

K. Tuchin

We calculate the total cross section for two scalar particles scattering at high energies in $λϕ^3$ theory in five dimensions, four of which are usual Minkowski ones and the fifth is compact. It is shown that the cross section is dominated by exchange of Pomeron whose intercept is larger than in usual four-dimensional case.

R. Bertle, M. Faber, J. Greensite, S. Olejnik

We study the dependence of the center-projected string tension on both the lattice size, and the number of gauge copies used for maximal center gauge fixing. We show that a recent finding of Bornyakov, Komarov, Polikarpov, and Veselov (hep-lat/0002017), indicating a substantial breakdown of center dominance in maximal center gauge, is only obtained for rathe

Ying Chen, Ji-Min Wu, Bing He

The SU(2) gluonic correlation functions, glueball effective masses in the $J^{P}=0^{+}$, $2^{+}$ and $0^{-}$ channels were calculated from the lattice classical gauge configurations which were obtained by smoothing the thermal gauge configurations through the improved cooling method. The instanton-induced attractive force in the $0^{+}$ channel and the repul

T. E. Browder, CLEO Collaboration

We report results of a search for $B\toτν$ in a sample of 9.7 million charged $B$ meson decays. The search uses both $πν$ and $\ellν\barν$ decay modes of the $τ$, and demands exclusive reconstruction of the companion $\bar B$ decay to suppress background. We set an upper limit on the branching fraction ${\cal B}(B\to τν) < 8.4\times 10^{-4}$ at 90% confidenc

John G. Learned

With the 1998 announcement of new evidence for muon neutrino disappearance observed by the Super-Kamiokande experiment, the more than a decade old atmospheric neutrino anomaly moved from a possible indication for neutrino oscillations to an almost inescapable implication. The evidence from all experiments is reviewed, and indications are presented that the o

R. Tresguerres, E. W. Mielke

In order to facilitate the application of standard renormalization techniques, gravitation should be decribed, if possible, in pure connection formalism, as a Yang-Mills theory of a certain spacetime group, say the Poincare or the affine group. This embodies the translational as well as the linear connection. However, the coframe is not the standard Yang-Mil

T. Uchiyama, T. Tomaru, D. Tatsumi, S. Miyoki

A mechanical quality factor of $1.1 \times 10^{7}$ was obtained for the 199 Hz bending vibrational mode in a monocrystalline sapphire fiber at 6 K. Consequently, we confirm that pendulum thermal noise of cryogenic mirrors used for gravitational wave detectors can be reduced by the sapphire fiber suspension.

Josef Kudrnovsky, Vaclav Drchal, Ilja Turek, Patrick Bruno

Ab initio formulations of the interlayer exchange coupling (IEC) between two, in general non-collinearly aligned magnetic slabs embedded in a non-magnetic spacer are reviewed whereby both the spacer and the magnetic slabs as well as their interfaces may be either ideal or random. These formulations are based on the spin-polarized surface Green function techn

Anatoly B. Kolomeisky, Michael E. Fisher

Inspired by the need for effective stochastic models to describe the complex behavior of biological motor proteins that move on linear tracks exact results are derived for the velocity and dispersion of simple linear sequential models (or one-dimensional random walks) with general waiting-time distributions. The concept of ``mechanicity&#39;&#39; is introduc

J. E. Hirsch

Within a simple model Hamiltonian, both superconductivity and metallic ferromagnetism can be understood as arising from lowering of kinetic energy as the ordered state develops, due to a reduction in the carriers effective mass, or equivalently, a bandwidth expansion. Experimental manifestation of this physics has been detected in both high Tc superconductor

J. M. Romero-Enrique, G. Orkoulas, A. Z. Panagiotopoulos, M. E. Fisher

Liquid-vapor coexistence curves and critical parameters for hard-core 1:1 electrolyte models with diameter ratios lambda = sigma_{-}/σ_{+}=1 to 5.7 have been studied by fine-discretization Monte Carlo methods. Normalizing via the length scale sigma_{+-}=(sigma_{+} + sigma_{-})/2 relevant for the low densities in question, both Tc* (=kB Tc sigma_{+-}/q^2 and

S. S. Banerjee, A. K. Grover, M. J. Higgins, G. I. Menon

A universal phase diagram for weakly pinned low-T$_c$ type-II superconductors is revisited and extended with new proposals. The low-temperature ``Bragg glass&#39;&#39; phase is argued to transform first into a disordered, glassy phase upon heating. This glassy phase, a continuation of the high-field equilibrium vortex glass phase, then melts at higher temper

J. L. Alonso, L. A. Fernandez, F. Guinea, V. Laliena

The Hybrid Monte Carlo algorithm is adapted to the simulation of a system of classical degrees of freedom coupled to non self-interacting lattices fermions. The diagonalization of the Hamiltonian matrix is avoided by introducing a path-integral formulation of the problem, in $d+1$ Euclidean space-time. A perfect action formulation allows to work on the conti

Andrea Cavagna, Alan J. Bray, Rui D. M. Travasso

We analytically study coarsening dynamics in a system with nonconserved scalar order parameter, when a uniform time-independent shear flow is present. We use an anisotropic version of the Ohta-Jasnow-Kawasaki approximation to calculate the growth exponents in two and three dimensions: for d=3 the exponents we find are the same as expected on the basis of sim

Christoph Jurecka, Wolfram Brenig

We present a unified account for the coupled single-hole- and spin-dynamics in the spin-gap phase of dimerized and frustrated spin-chains and two-leg spin ladders. Based on the strong dimer-limit of a one-dimensional $t_123$-$J_123$-model a diagrammatic approach is presented which employs a mapping of the spin-Hamiltonian onto a pseudo-fermion bond-boson mod

D. Porras, J. Fernandez-Rossier, C. Tejedor

Scanning tunneling microscopy permits to image the Kondo resonance of a single magnetic atom adsorbed on a metallic surface. When the magnetic impurity is placed at the focus of an elliptical quantum corral, a Kondo resonance has been recently observed both on top of the impurity and on top of the focus where no magnetic impurity is present. This projection

Ivo Souza, Richard M. Martin, Nicola Marzari, Xinyuan Zhao

We have constructed maximally-localized Wannier functions for prototype structures of solid molecular hydrogen under pressure, starting from LDA and tight-binding Bloch wave functions. Each occupied Wannier function can be associated with two paired protons, defining a ``Wannier molecule&#39;&#39;. The sum of the dipole moments of these ``molecules&#39;&#39;

A. Komnik, R. Egger

We study nonlinear transport for two coupled one-dimensional quantum wires or carbon nanotubes described by Luttinger liquid theory. Transport properties are shown to crucially depend on the contact length $L_c$. For a special interaction strength, the problem can be solved analytically for arbitrary $L_c$. For point-like contacts and strong interactions, a

Stefan Scheidl, Felix von Oppen

We study the effect of disorder on quantum Hall smectics within the framework of an elastic theory. Based on a renormalization group calculation, we derive detailed results for the degrees of translational and orientational order of the stripe pattern at zero temperature and carefully map out the disorder and length-scale regimes in which the system effectiv

Klaus Capelle

The anomalous Darwin term, one of the recently derived relativistic corrections to the conventional theory of superconductivity, is analysed in detail. A new derivation of this term, much simpler than that given originally, is presented and used to interpret the term physically, in terms of fluctuations of the relativistic wave packet describing the paired e

J. L. Alonso, L. A. Fernandez, F. Guinea, V. Laliena

It has been recently shown that the double exchange Hamiltonian, with weak antiferromagnetic interactions, has a richer variety of first and second order transitions than previously anticipated, and that such transitions are consistent with the magnetic properties of manganites. Here we present a thorough discussion of the variational Mean Field approach tha

G. Casati, G. Mantica, D. L. Shepelyansky

We study the dynamics of a quantum rotator kicked according to the almost-periodic Fibonacci sequence. A special numerical technique allows us to carry on this investigation for as many as $10^{12}$ kicks. It is shown that above a critical kick strength the excitation of the system is well described by regular diffusion, while below this border it becomes an

G. Ravikumar, V. C. Sahni, A. K. Grover, S. Ramakrishnan

The peak effect in weakly pinned superconductors is accompanied by metastable vortex states. Each metastable vortex configuration is characterized by a different critical current density J_c, which mainly depends on the past thermomagnetic history of the superconductor. A recent model [G. Ravikumar, et al, Phys. Rev. B 61, R6479 (2000)] proposed to explain t

Kensuke Fukuda, Hideki Takayasu, Misako Takayasu

We perform a simplified Ethernet traffic simulation in order to clarify the physical mechanism of the phase transition behavior which has been experimentally observed in the flow density fluctuation of Internet traffic. In one phase traffics from nodes connected with an Ethernet cable are mixed, and in the other phase, the nodes alternately send bursts of pa

Antonio H. Castro Neto

We propose a model for a spatially modulated collective state of superconducting cuprates in which the electronic properties vary locally in space. In this model the regions of higher hole density (called stripes) are described as Luttinger liquids and the regions of lower density (antiferromagnetic ladders) as an interacting bosonic gas of d$_{x^2-y^2}$ hol

J. Aumentado, V. Chandrasekhar

We have measured the electrical transport of submicron ferromagnets (Ni) in contact with a mesoscopic superconductor (Al) for a range of interface resistances. In the geometry measured, the interface and the ferromagnet are measured separately. The ferromagnet itself shows no appreciable superconducting proximity effect, but the ferromagnet/superconductor in

Jian-Ming Tang

The structure of a quantized vortex in a Bose-Einstein Condensate is investigated using the projection method developed by Peierls, Yoccoz, and Thouless. This method was invented to describe the collective motion of a many-body system beyond the mean-field approximation. The quantum fluctuation has been properly built into the variational wave function, and

S. J. Mitchell, G. Brown, P. A. Rikvold

We present dynamic Monte Carlo simulations of a lattice-gas model for bromine electrodeposition on single-crystal silver (100). This system undergoes a continuous phase transition between a disordered phase at low electrode potentials and a commensurate c(2X2) phase at high potentials. The lattice-gas parameters are determined by fitting simulated equilibriu

M. Reed, Steven D. Kawaler, M. Sean O&#39;Brien

PG 2131+066 is a composite-spectrum binary with a hot pulsating PG 1159-type pre-white dwarf and an early M-type main sequence star. Analysis of Whole Earth Telescope observations of the pulsating pre-white dwarf component provided an asteroseismological determination of its mass, luminosity, and effective temperature. These determinations allowed Kawaler et

Magdalen Normandeau

A conical void in the Galactic HI within the Perseus arm has been proposed to be a chimney. However, Halpha data suggest that the structure may be closed at higher latitudes and therefore is a superbubble rather than a chimney. Recent observations have extended our view of the HI and the radio continuum emission to higher latitudes, up to 8 degrees;. The new

W. H. de Vries, C. P. O&#39;Dea, P. D. Barthel, C. Fanti

We present near-infrared J and K band imaging of a sample of powerful radio source host galaxies with the Hubble Space Telescope NICMOS2 camera. These sources have been selected on their double lobed radio structure, and include a wide range of projected radio source sizes. The largest projected linear sizes range from the compact Gigahertz Peaked Spectrum (

Demos Kazanas, Sergei Nayakshin

We test the &#34;reprocessing paradigm&#34; of the optical -- UV AGN variability by detailed modeling of the correlated X-ray -- optical (3590 and 5510 Angstrem) variability of the recent multiwavelength campaign of NGC 3516. We produce model optical light curves by convolving the observed X-ray flux with the response function of an infinite, thin accretion

Ben A. Mazin, Robert J. Brunner

In this paper we explore the application of cryogenic imaging spectrophotometers. Prototypes of this new class of detector, such as superconducting tunnel junctions (STJs) and transition edge sensors (TESs), currently deliver low resolution imaging spectrophotometry with high quantum efficiency (70-100%) and no read noise over a wide bandpass in the visible

J. D. Monnier, W. C. Danchi, D. S. Hale, P. G. Tuthill

Using the U.C. Berkeley Infrared Spatial Interferometer with an RF filterbank, the first interferometric observations of mid-infrared molecular absorption features of ammonia (NH_3) and silane (SiH_4) with very high spectral resolution (R ~ 100000) were made. Under the assumptions of spherical symmetry and uniform outflow, these new data permitted the molecu

Regina E. Schulte-Ladbeck, Ulrich Hopp, Laura Greggio, Mary M. Crone

We observed the Blue Compact Dwarf/Wolf-Rayet galaxy Mrk 178 with the NICMOS camera aboard HST. The galaxy is well resolved into individual stars in the near-IR; photometry in J and H yields color-magnitude diagrams containing 791 individual point sources. We discuss the stellar content, drawing particular attention to the intermediate age and/or old stars.

M. S. Seigar, P. A. James

We have imaged a sample of 20 face-on spiral galaxies in Hαand in the near-IR K-band (2.2 microns), in order to determine the location and strength of star formation with respect to perturbations in the old stellar population. We found that star formation rates are significantly enhanced near K-band arms. If K-band light is dominated by emission from old sta

L. K. Deutsch, M. Kassis, N. Smith, J. L. Hora

We describe multi-wavelength (8--20 micron), diffraction-limited, mid-infrared images of the OMC-1 cloud core in Orion, covering an approximately two arcminute area around the Trapezium and BN/KL regions. We have detected mid-infrared emission at the locations of a subset of the previously identified proplyds in the Orion Nebula along with two new infrared s

M. Heydari-Malayeri, P. Royer, G. Rauw, N. R. Walborn

Based on imaging and spectroscopy obtained at the ESO NTT telescope and using an efficient image analysis algorithm, we study the core of the LMC OB association LH13, particularly the two compact stellar clusters Sk-6641 and HNT in the HII, region N11C. We resolve Sk-6641 into 15 components and for the first time the HNT cluster into 70 stars, and derive pho

Michael P. Geyer, Andreas Burkert

The effect of gas ejection on the structure and binding energy of newly formed stellar clusters is investigated. The star formation efficiency (SFE), necessary for forming a gravitationally bound stellar cluster, is determined. Two sets of numerical N-body simulations are presented: As a first simplified approach we treat the residual gas as an external pote

A. Heger, K. Langanke, G. Martinez-Pinedo, S. E. Woosley

Improved values for stellar weak interaction rates have been recently calculated based upon a large shell model diagonalization. Using these new rates (for both beta decay and electron capture), we have examined the presupernova evolution of massive stars in the range 15-40 Msun. Comparing our new models with a standard set of presupernova models by Woosley

G. Gavazzi, P. Franzetti, M. Scodeggio, A. Boselli

We present near-infrared H-band (1.65 micron) surface brightness profile decomposition for 1157 galaxies in five nearby clusters of galaxies: Coma, A1367, Virgo, A262 and Cancer, and in the bridge between Coma and A1367 in the &#34;Great Wall&#34;. The optically selected (m_p<=16.0) sample is representative of all Hubble types, from E to Irr+BCD, except dE a

Tong-Jie Zhang, Xiang-Ping Wu

A combination of the X-ray imaging and SZ measurements of clusters permits an indirect determination of the radial temperature profiles of intracluster gas, which requires no assumption about the dynamical properties and the equation of state for clusters. A comparison of such a derived gas temperature with that given by the X-ray spectral analysis constitut

Leonardo Testi, Francesco Palla, Antonella Natta

We present the results of a recent near-infrared survey of the fields surrounding a large sample of intermediate-mass pre-main-sequence (Herbig Ae/Be) stars. While late-type Be and Ae stars are never associated with conspicuous groups of young lower mass stars, early-type Be stars are usually found within rich clusters. This finding has been tested against p

Jimmy A. Irwin, Craig L. Sarazin, Joel N. Bregman

We analyze archival ROSAT HRI, ROSAT PSPC, and ASCA data of the X-ray faint early-type galaxy NGC4697. The joint ROSAT PSPC + ASCA spectrum is fit by a two-component thermal model, a MEKAL model with kT_{MEKAL}=0.26^{+0.04}_{-0.03} keV with low metallicity and a bremsstrahlung model with kT_{BREM}=5.2^{+3.0}_{-1.6} keV. A similar model was found to fit the s

Alice C. Quillen, Donald R. Garnett

We re-examine the age-velocity dispersion relation in the solar neighborhood using improved stellar age estimates that are based on Hipparcos parallaxes and recent stellar evolution calculations. The resulting relation shows that the Milky Way stellar disk was relatively quiescent, suffering little heating or dispersion increase between 3 and 9 Gyrs. However

E. E. Fenimore, E. Ramirez-Ruiz

We show that the time variability of a gamma-ray burst (GRB) appears to be correlated with the absolute luminosity of the burst: smooth bursts are intrinsically less luminous. This Cepheid-like relationship can be used to determine the redshift of a GRB from parameters measured solely at gamma-ray energies. The relationship is based on only seven events at p

J. J. Binney, J. A. Sellwood

The paper claimed that significant radial migration of stars in a stellar disk like that of the Milky Way could not occur. We now think that while the treatment of the effects of molecular clouds was correct, the paper seriously underestimated the ability of spiral arms to shift the radii of stars that corotate with them. Consequently, it is likely that sign

Mohsen Alishahiha, Yaron Oz, Jorge G. Russo

We construct dual supergravity descriptions of field theories and little string theories with light-like non-commutativity. The field theories are realized on the world-volume of Dp branes with light-like NS $B$ field and M5 branes with light-like $C$ field. The little string theories are realized on the world-volume of NS5 branes with light-like RR $A$ fiel

W. N. Brandt, N. S. Schulz

We present the first grating-resolution X-ray spectra of the X-ray binary Cir X-1, obtained with the High Energy Transmission Grating Spectrometer on Chandra. These reveal a rich set of lines from H-like and/or He-like Ne, Mg, Si, S and Fe detected with a high signal-to-noise ratio. The lines are broad (+/- 2000 km/s) and show P Cygni profiles. The absorptio

A. Iqbal, A. H. Toor

Evolutionarily Stable Strategy (ESS) in classical game theory is a refinement of Nash equilibrium concept. We investigate the consequences when a small group of mutants using quantum strategies try to invade a classical ESS in a population engaged in symmetric bimatrix game of Prisoner&#39;s Dilemma. Secondly we show that in an asymmetric quantum game betwee

A. V. Belitsky, Xiangdong Ji, Wei Lu, Jonathan Osborne

Following a previous study of the one-loop factorization of the nonsinglet $g_2$ structure function of the nucleon, we present in this paper the next-to-leading order coefficient functions in the singlet sector. To obtain the result, the partonic processes of virtual Compton scattering off two and three &#34;on-shell&#34; gluons are calculated. A key step in

Elliott H. Lieb, Jan Philip Solovej

The model considered here is the `jellium&#39; model in which there is a uniform, fixed background with charge density $-eρ$ in a large volume $V$ and in which $N=ρV$ particles of electric charge $+e$ and mass $m$ move --- the whole system being neutral. In 1961 Foldy used Bogolubov&#39;s 1947 method to investigate the ground state energy of this system for

L. A. Anchordoqui, M. Kirasirova, T. P. McCauley, S. Reucroft

A re-examination of the atmospheric cascade profile of the highest energy cosmic ray is presented. The study includes air-shower simulations considering different cross sections, particle multiplicity and variation of the hadronic-event-generator to model interactions above 200 GeV. The analysis provides evidence that a medium mass nucleus primary reproduces

Hideki Ishihara

Causal structure of the brane universe with respect to null geodesics in the bulk spacetime is studied. It is pointed out that apparent causality violation is possible for the brane universe which contains matter energy. It is also shown that there is no &#39;horizon problem&#39; in the Friedmann-Robertson-Walker brane universe.

G. Orlandini, T. G. Steele, D. Harnett

Techniques for using Gaussian QCD sum-rules to predict hadronic resonance properties are developed for single-resonance and two-resonance phenomenological models, and criteria are developed for determining which of these models is required for analyzing a particular hadronic channel. The vector current sum-rule coupled to the $ρ$ meson is shown to be consist

I. Prandoni, L. Gregorini, P. Parma, H. R. de Ruiter

This paper is part of a series reporting the results of the Australia Telescope ESO Slice Project (ATESP) radio survey obtained at 1400 MHz with the Australia Telescope Compact Array (ATCA) over the region covered by the ESO Slice Project (ESP) galaxy redshift survey. The survey consists of 16 radio mosaics with ~8&#34;x14&#34; resolution and uniform sensiti

Ekaterina Christova, Elliot Leader

We present a strategy for the systematic extraction of a vast amount of detailed information on polarized parton densities and fragmentation functions from semi-inclusive deep inelastic scattering l+N -> l+h+X, in both LO and NLO QCD. A method is suggested for estimating the errors involved in the much simpler, and therefore much more attractive, LO analysis

I. Prandoni, L. Gregorini, P. Parma, H. R. de Ruiter

This paper is the first of a series reporting the results of the Australia Telescope ESO Slice Project (ATESP) radio survey obtained at 1400 MHz with the Australia Telescope Compact Array (ATCA) close to the South Galactic Pole (SGP) over the region covered by the ESO Slice Project (ESP) galaxy redshift survey (decl. ~ -40 degr). The survey consists of 16 ra

I. Jack, D. R. T. Jones, S. Parsons

We consider the renormalisation of the Fayet-Iliopoulos D-term in a softly-broken abelian supersymmetric theory, and calculate the associated beta-function through three loops. We show that there exists (at least through three loops) a renormalisation group invariant trajectory for the coefficient of the D-term, corresponding to the conformal anomaly solutio

Tim M. P. Tait, C. -P. Yuan

Production of single top quarks at a high energy hadron collider is studied as a means to identify physics beyond the standard model related to the electroweak symmetry breaking. The sensitivity of the $s$-channel $W^*$ mode, the $t$-channel $W$-gluon fusion mode, and the \tw mode to various possible forms of new physics is assessed, and it is found that the

Igor Frenkel, Naihuan Jing, Weiqiang Wang

We establish a twisted analog of our recent work on vertex representations and the McKay correspondence. For each finite group $Γ$ and a virtual character of $Γ$ we construct twisted vertex operators on the Fock space spanned by the super spin characters of the spin wreath products $Γ\wr\widetilde{S}_n$ of $Γ$ and a double cover of the symmetric group $S_n$

J. J. Lin, L. Y. Kao

We have systematically investigated the low-temperature electron dephasing times $τ_ϕ$ in more than 40 three-dimensional polycrystalline impure metals with distinct material characteristics. In all cases, a saturation of the dephasing time is observed below about a (few) degree(s) Kelvin, depending on samples. The value of the saturated dephasing time $τ_0$

A. Retey, J. A. M. Vermaseren

We present the analytic next-to-next-to-leading QCD calculation of some higher moments of deep inelastic structure functions in the leading twist approximation. We give results for the moments $N$=1,3,5,7,9,11,13 of the structure function $F_3$. Similarly we present the moments $N$=10,12 for the flavour singlet and $N$=12,14 for the non-singlet structure fun

Bjorn Andreas, Gottfried Curio, Ruben Minasian

Tadpole cancellation in F-theory on an elliptic Calabi-Yau fourfold $X\to B_3$ demands some spacetime-filling three-branes (points in $B_3$). If moved to the discriminant surface, which supports the gauge group, and dissolved into a finite size instanton, the second Chern class of the corresponding bundle $E$ is expected to give a compensating contribution.

Vijay Balasubramanian, Eric Gimon, Djordje Minic, Joachim Rahmfeld

Exploring the role of conformal theories of gravity in string theory, we show that the minimal (N=2) gauged supergravities in five dimensions induce the multiplets and transformations of N=1 four dimensional conformal supergravity on the spacetime boundary. N=1 Poincare supergravity can be induced by explicitly breaking the conformal invariance via a radial

P. Braun-Munzinger, J. Stachel

To investigate a recent proposal that J/$ψ$ production in ultra-relativistic nuclear collisions is of thermal origin we have reanalyzed the data from the NA38/50 collaboration within a thermal model including charm. Comparison of the calculated with measured yields demonstrates the non-thermal origin of hidden charm production at SPS energy. However, the rat

Adam Lipowski

We study a one-dimensional model which undergoes a transition between an active and an absorbing phase. Monte Carlo simulations supported by some additional arguments prompted as to predict the exact location of the critical point and critical exponents in this model. The exponents $δ=0.5$ and $z=2$ follows from random-walk-type arguments. The exponents $β=

Kengo Maeda, Takashi Torii, Makoto Narita, Shigeaki Yahikozawa

We investigate how much a first-quantized charged bosonic test string gets excited after crossing a shock wave generated by a charged particle with mass $\tilde{M}$ and charge $\tilde{Q}$. On the basis of Kaluza-Klein theory, we pay attention to a closed string model where charge is given by a momentum along a compactified extra-dimension. The shock wave is

M. Cvetic, H. Lu, C. N. Pope

We review general domain-wall solutions supported by a delta-function source, together with a single pure exponential scalar potential in supergravity. These scalar potentials arise from a sphere reduction in M-theory or string theory. There are several examples of flat (BPS) domain walls that lead to a localisation of gravity on the brane, and for these we

Pijush K. Ghosh

We show that the supersymmetric rational Calogero-Moser-Sutherland (CMS) model of A_{N+1}-type is equivalent to a set of free super-oscillators, through a similarity transformation. We prescribe methods to construct the complete eigen-spectrum and the associated eigen-functions, both in supersymmetry preserving as well as supersymmetry breaking phases, from

John Michael Williams

The symmetry of the problem of the apparent deficit in upward-going atmospheric muon neutrinos reveals two possible, nonexclusive kinds of solution: Nonlinearity in distance or nonlinearity in angle of observation. Nonlinearity in distance leads to the most popular theory for the atmospheric problem, neutrino flavor oscillations. If the observed deficit is c

Hans-Karl Janssen, Olaf Stenull

We study random lattice networks consisting of resistor like and diode like bonds. For investigating the transport properties of these random resistor diode networks we introduce a field theoretic Hamiltonian amenable to renormalization group analysis. We focus on the average two-port resistance at the transition from the nonpercolating to the directed perco

Yukitoshi Motome, Nobuo Furukawa

Ferromagnetic transition in three-dimensional double-exchange models is studied by the Monte Carlo method. Critical temperature $T_{\rm c}$ is precisely determined by finite-size scaling analysis. Strong spin fluctuations in this itinerant system significantly reduce $T_{\rm c}$ from mean-field estimates. By choosing appropriate parameters, obtained values o

M. Ave, J. A. Hinton, R. A. Vazquez, A. A. Watson

Using data from inclined events ($60^{\circ}<θ<80^{\circ}$) recorded by the Haverah Park shower detector, we show that above 10^19 eV less than 30% of the primary cosmic rays can be photons or iron nuclei at the 95% confidence level. Above 4 10^19 eV less than 55% of the cosmic rays can be photonic at the same confidence level. These limits place important c

Shin&#39;ichi Nojiri, Sergei D. Odintsov

The model of d5 higher derivative (HD) gravity admitting Schwarzschild--anti de Sitter Black Hole (S-AdS BH) as exact solution is considered. The surface counterterms are added to the complete action, they are fixed by the condition of finiteness of bulk AdS spacetime when brane goes to infinity. As a result the brane (observable Universe) is defined dynamic

Satoshi Matsuda, Shigenori Seki

Tachyonic Kaluza-Klein modes normally appear from the compactification of extra timelike dimensions with scale $L$ and lead to some instabilities of physical systems. We calculate the contribution of tachyonic gravitons to the self energies of spherical massive bodies of radius $R$ and discuss their possible gravitational stability. We find that some spheric

David J. Gross, Nikita A. Nekrasov

We continue our study of solitons in noncommutative gauge theories and present an extremely simple BPS solution of N=4 U(1) noncommutative gauge theory in 4 dimensions, which describes N infinite D1 strings that pierce a D3 brane at various points, in the presence of a background B-field in the Seiberg-Witten limit. We call this solution the N-fluxon. For N=

Jonas Soderholm, Gunnar Bjork, Alexei Trifonov

We present a new derivation of the unpolarized quantum states of light, whose general form was first derived by Prakash and Chandra [Phys. Rev. A 4, 796 (1971)]. Our derivation makes use of some basic group theory, is straightforward, and offers some new insights.

Jonathan Walgate, Anthony J. Short, Lucien Hardy, Vlatko Vedral

We consider one copy of a quantum system prepared in one of two orthogonal pure states, entangled or otherwise, and distributed between any number of parties. We demonstrate that it is possible to identify which of these two states the system is in by means of local operations and classical communication alone. The protocol we outline is both completely reli

M. S. Shahriar, T. Zelevinsky, P. R. Hemmer

We have shown via explicit analysis as well as numerical simulation the design of two large angle interferometers employing two-photon pulses. The first one uses the technique of adiabatic following in a dark state to produce a large splitting angle atomic interferometer that is capable of producing one dimensional gratings with spacings as small as 2 nm. Un

S. Collin, F. Pardo, R. Teissier, J. -L. Pelouard

Complex photonic band structures (CPBS) of transmission metallic gratings with rectangular slits are shown to exhibit strong discontinuities that are not evidenced in the usual energetic band structures. These discontinuities are located on Wood&#39;s anomalies and reveal unambiguously two different types of resonances, which are identified as horizontal and