September 1998 arXiv papers — page 4

Craig J. Hogan

An overview is presented of possible cosmologically distant sources of gravitational wave backgrounds, especially those which might produce detectable backgrounds in the LISA band between 0.1 and 100 mHz. Examples considered here include inflation-amplified vacuum fluctuations in inflaton and graviton fields, bubble collisions in first-order phase transition

Santiago Torres, Enrique Garcia-Berro, Jordi Isern

The white dwarf luminosity function has proven to be an excellent tool to study some properties of the galactic disk such as its age and the past history of the local star formation rate. The existence of an observational luminosity function for halo white dwarfs could provide valuable information about its age, the time that the star formation rate lasted,

Sidney van den Bergh

A great burst of cluster formation increased the rate at which open clusters were formed in the Large Magellanic Cloud 3-5 Gyr ago by at least an order of magnitude. On the other hand the rate of star formation ~ 4 Gyr appears to have increased by a factor of only 2-4. This shows that the rate of cluster formation is not a good tracer of the rate at which st

W. A. Dziembowski, G. Fiorentini, B. Ricci, R. Sienkiewicz

The problem of measuring the solar age by means of helioseismology hasbeen recently revisited by Guenther & Demarque (1997) and by Weiss & Schlattl (1998). Different best values for $t_{\rm seis}$ and different assessment of the uncertainty resulted from these two works. We show that depending on the way seismic data are used, one may obtain the value $t_{\r

Shude Mao, H. J. Mo, Simon D. M. White

We review some of our recent progress in modelling the formation of disk galaxies in the framework of hierarchical structure formation. Our model is not only consistent with the local observations, but also provides a good description of disk evolution out to redshift z~1. We use this model to interpret recent observational results on Lyman-break galaxies (L

S. Tremaine

This report provides a summary and bibliography for the research activities at the Princeton University Observatory and Department of Astrophysical Sciences during the period July 1, 1997 to June 30, 1998.

Nicholas B. Suntzeff, Alistair R. Walker, Verne V. Smith, Robert P. Kraft

We present both low and high-dispersion abundance analyses of giants drawn from the zero proper motion sample near NGC 121. For the sample of 35 stars, the mean metallicity of the SMC field near NGC 121 is [Fe/H]=-1.3 with a real dispersion of 0.4 dex. The most metal-rich stars are at -0.5 dex and the most metal-poor stars at -2.1 dex. The velocity dispersio

James M. Stone, Eve C. Ostriker, Charles F. Gammie

We report results of a three dimensional, high resolution (up to 512^3) numerical investigation of supersonic compressible magnetohydrodynamic turbulence. We consider both forced and decaying turbulence. The model parameters are appropriate to conditions found in Galactic molecular clouds. We find that the dissipation time of turbulence is of order the flow

Alan Owens, M. Guainazzi, T. Oosterbroek, A. Orr

We present an analysis of the X-ray absorption properties of 6 gamma-ray burst (GRB) afterglows measured with BeppoSAX. Between 8 hrs and 20 hrs after the initial GRB trigger, individual spectra can be described by a power-law with a photon index of ~2 and absorption marginally consistent with the galactic value. Taken collectively, the data are inconsistent

Edouard Audit, John F. L. Simmons

The measurement of the integrated optical polarization of weakly gravitationally lensed galaxies can provide considerable constraints on lens models. The method outlined depends on fact that the orientation of the direction of optical polarization is not affected by weak gravitational lensing. The angle between the semi-major axis of the imaged galaxy and th

Sylvie Vauclair

Element settling inside the Sun now becomes detectable from the comparison of the observed oscillation modes with the results of the theoretical models. This settling is due, not only to gravitation, but also to thermal diffusion and radiative acceleration (although this last effect is small compared to the two others). It leads to abundance variations of he

F. R. Bouchet, S. Prunet, S. K. Sethi

One goal of CMB data analysis is to combine data at different frequencies, angular resolutions, and noise levels in order to best extract the component with a Plankian spectral behaviour. A multi-frequency Wiener filtering method has been proposed in this context by Bouchet, Gispert and Puget (1995) and in parallel by Tegmark and Efstathiou (1996). As shown

Gabriele Ghisellini

Estimates on different scales of the power of relativistic bulk motion in extragalactic and galactic jets are presented. The power in the jets and the power produced by the accretion disk are found to be roughly equal. This may suggest an important role of the magnetic field in extracting both the gravitational energy of the accreting matter and the rotation

M. Scodeggio, R. Giovanelli, M. P. Haynes

We present here central velocity dispersion measurements for 325 early-type galaxies in eight clusters and groups of galaxies, including new observations for 212 galaxies. The clusters and groups are the A262, A1367, Coma (A1656), A2634, Cancer and Pegasus clusters, and the NGC 383 and NGC 507 groups. The new measurements were derived from medium dispersion

M. Scodeggio, R. Giovanelli, M. P. Haynes

As part of a project to compare the Fundamental Plane and Tully-Fisher distance-scales, we present here I band CCD photometry for 636 early-type galaxies in 8 clusters and groups of galaxies. These are the A262, A1367, Coma (A1656), A2634, Cancer and Pegasus clusters, and the NGC 383 and NGC 507 groups. Sample selection, cluster properties, and cluster membe

Stefan C. Keller, Michael S. Bessell

The presence of an anomalously large population of Be stars in the young cluster NGC 330 in the SMC has been noted by Feast (1972), Bessell & Wood (1993), Grebel (1996) and most recently Keller et al. (1998). We present results from follow-up medium resolution spectra of the bright Be stars identified in Keller et al. (1998) and in the spectroscopic study of

D. Anselmi

We determine the spectrum of currents generated by the operator product expansion of the energy-momentum tensor in N=4 super-symmetric Yang-Mills theory. Up to the regular terms and in addition to the multiplet of the stress tensor, three current multiplets appear, Sigma, Xi and Upsilon, starting with spin 0, 2 and 4, respectively. The OPE's of these new

A. Udalski, G. Pietrzynski, P. Wozniak, M. Szymanski

We present {\it UBVI} photometry of the eclipsing binary HV2274 - the system which has been recently used for distance determination to the LMC by Guinan et al. (1998). We determine the interstellar reddening to the star, E(B-V)=0.149+/-0.015 mag, based on observed colors of the star. This value is in excellent agreement with the mean reddening towards HV227

S. Bellucci, E. Ivanov, S. Krivonos

We describe the partial breaking of $N=1 D=10$ supersymmetry down to $(1,0) d=6$ supersymmetry within the non-linear realization approach. The basic Goldstone superfield associated with this breaking is shown to be the $(1,0) d=6$ hypermultiplet superfield $q^{ia}$ subjected to a non-linear generalization of the standard hypermultiplet superfield constraint.

Paulo F. Farinas, Kevin S. Bedell, Nelson Studart

We report the existence of regimes of the two dimensional Fermi liquid that show unusual conservation of the spin current and may be tuned by varying some parameter like the density of fermions. We show that for reasonable models of the effective interaction the spin current may be conserved in general in 2d, not only for a particular regime. Low temperature

We-Fu Chang, Hsiang-nan Li, Hoi-Lai Yu

We apply perturbative QCD factorization theorems to inclusive heavy hadron decays, and obtain simultaneously a low semileptonic branching ratio $B(B\to Xl\barν)=10.16%$, the average charm yield $<n_c>=1.17$ per $B$ decay, a small lifetime ratio $τ(Λ_b)/τ(B_d)=0.78$, and the correct absolute decay widths of the $B$ meson and of the $Λ_b$ baryon.

P. Ao

Starting from the microscopic theory of Bardeen-Cooper-Schrieffer (BCS) for the fermionic superfluids, we show that the vortex dynamics can be followed naturally by extending Feynman&#39;s influence functional approach to incorporate the transverse force. There is a striking mutual independence of the transverse and longitudinal influences: The former has th

C. A. Ogilvie

This talk reviews the physics of dense, strongly interacting matter. The newly acquired experimental data on strangeness production in heavy-ion reactions from 1-10 AGeV is used to probe the physics of in-medium properties of kaons, multi-body collisions, and the search for the baryon-rich quark-gluon plasma.

Paul J. Sanders, Tom S. Wilde

The coexponent of a finite p-group is introduced and we consider how the nilpotency class is bounded in terms of this invariant.

S. A. Gogilidze, Yu. S. Surovtsev

Local symmetries of the action for a relativistic particle with curvature and torsion of its world curve in the (2+1)-dimensional space-time are studied. With the help of the method, worked out recently by the authors (Phys.Rev., D56, 1135, 1142 (1997)), first the local-symmetry transformations are obtained both in the phase and configuration space. At the c

T. M. Aliev, M. Savci

The radiative &#34;B_c -> tau nu_tau gamma&#34; decay is analyzed in the standard model. The branching ratio of this decay is calculated and the contributions of the Bremstrahlung and structure dependent parts are compared. It is shown that this decay can be detected at LHC.

M. Fukugita, M. Tanimoto, T. Yanagida

We construct phenomenological quark-lepton mass matrices based on S$_3$ permutation symmetry in a manner fully compatible with SU(5) grand unification. The Higgs particles we need are {\bf 5}, {\bf 45} and their conjugates. The model gives a charge $-$1/3 quark vs charged lepton mass relation, and also a good fit to mass-mixing relations for the quark sector

V. V. Burov, A. V. Molochkov, G. I. Smirnov

The evolution of the EMC effect as a function of atomic mass $A$ is considered for the first time for the lightest nuclei, D, $^3H$, $^3He$ and $^4He$, with an approach based on the Bethe-Salpeter formalism. We show that the pattern of the oscillation of the ratio $r^A(x) = F_2^A/F_2^N(D)$ varies with $A$, unlike the pattern for nuclei with masses $A > 4$, w

E. N. Glass, Jonathan Kress

The computational use of Killing potentials which satisfy Penrose&#39;s equation is discussed. Penrose&#39;s equation is presented as a conformal Killing-Yano equation and the class of possible solutions is analyzed. It is shown that solutions exist in spacetimes of Petrov type O, D or N. In the particular case of the Kerr background, it is shown that there

Lior M. Burko

We study analytically the spacelike singularity inside a spherically-symmetric, charged black hole coupled to a self-gravitating spherical massless scalar field. We assume spatial homogeneity, and find a generic solution in terms of a formal series expansion. This solution is tested against fully-nonlinear and inhomogeneous numerical simulations. We find ful

Ido Dagan, Lillian Lee, Fernando C. N. Pereira

In many applications of natural language processing (NLP) it is necessary to determine the likelihood of a given word combination. For example, a speech recognizer may need to determine which of the two word combinations ``eat a peach&#39;&#39; and ``eat a beach&#39;&#39; is more likely. Statistical NLP methods determine the likelihood of a word combination

Didier Sornette, Daniel Zajdenweber

At what level should government or companies support research? This complex multi-faceted question encompasses such qualitative bonus as satisfying natural human curiosity, the quest for knowledge and the impact on education and culture, but one of its most scrutinized component reduces to the assessment of economic performance and wealth creation derived fr

E. Kanzieper, V. Freilikher

A formalism for study of spectral correlations in non-Gaussian, unitary invariant ensembles of large random matrices with strong level confinement is reviewed. It is based on the Shohat method in the theory of orthogonal polynomials. The approach presented is equally suitable for description of both local and global spectral characteristics, thereby providin

Z. Y. Weng, D. N. Sheng, C. S. Ting

In this paper we explore the incommensurate spatial modulation of spin-spin correlations as the intrinsic property of the doped Mott insulator, described by the $t-J$ model. We show that such an incommensurability is a direct manifestation of the phase string effect introduced by doped holes in both one- and two-dimensional cases. The magnetic incommensurate

Z. Y. Weng, D. N. Sheng, C. S. Ting

A mean-field treatment of the phase string effect in the $t-J$ model is presented. Such a theory is able to unite the antiferromagnetic (AF) phase at half-filling and metallic phase at finite doping within a single theoretical framework. We find that the low-temperature occurrence of the AF long range ordering (AFLRO) at half-filling and superconducting cond

V. Ya. Demikhovskii, D. I. Kamenev, G. A. Luna-Acosta

Quantum weak chaos is studied in a perturbed degenerate system --- a charged particle interacting with a monochromatic wave in a transverse magnetic field. The evolution operator for an arbitrary number of periods of the external field is built and its structure is explored in terms of the QE (quasienergy eigenstates) under resonance condition (wave frequenc

Itzhack Dana, Yaakov Rutman, Mario Feingold

Band Husimi distributions (BHDs) are introduced in the quantum-chaos problem on a toral phase space. In the framework of this phase space, a quantum state must satisfy Bloch boundary conditions (BCs) on a torus and the spectrum consists of a finite number of levels for given BCs. As the BCs are varied, a level broadens into a band. The BHD for a band is defi

H. K. C. Yee

This article describes the various photometric techniques currently being used, including some preliminary results from the large CNOC2 redshift survey. It also presents a critical look at the reliability of the photometric redshift technique, in part using the HDF results from various groups as a case study.

R. D. Blum, A. Damineli

We present 2 um narrow-band images of the core H II region in the Galactic star forming region Sagittarius D. The emission-line images are centered on 2.17 um (Brgamma) and 2.06 um (He I). The H II region appears at the edge of a well defined dark cloud, and the morphology suggests a blister geometry as pointed out in earlier radio continuum work. There is a

Yoshiaki Taniguchi, Youichi Ohyama

Recently Taniguchi and Ohyama found that the higher $^{12}$CO to $^{13}$CO integrated intensity ratios at a transition $J$=1--0, $R = I(^{12}$CO)$/I(^{13}$CO) $\gtrsim 20$, in a sample of starburst merging galaxies such as Arp 220 are mainly attributed to the depression of $^{13}$CO emission with respect to $^{12}$CO. Investigating the same sample of galaxie

O. Lahav, B. X. Santiago, A. M. Webster, M. A. Strauss

We re-examine the existence and extent of the planar structure in the local galaxy density field, the so-called Supergalactic Plane (SGP). This structure is studied here in three dimensions using both the new Optical Redshift Survey (ORS) and the IRAS 1.2 Jy redshift survey. The density contrast in a slab of thickness of 20 Mpc/h and diameter of 80 Mpc/h ali

Amir Levinson

A large fraction of the AGNs detected by EGRET exhibit strong variability in many wavebands- from radio to the highest energy gamma-rays observed. The origin of the transient emission in blazars is presumably associated with relativistic jets. In this talk plausible variability mechanisms that may operate in blazars are discussed.

Nick Kaiser

In this introductory talk I give an elementary overview of the development, current status, and near term outlook for three probes of large scale structure; galaxy clustering, bulk flows and weak lensing observations.

Roger Ellman

It is now possible to partially deflect gravitation away from an object so that the gravitational attraction on the object is reduced. That effect makes it possible to extract energy from the gravitational field, which makes the generation of gravito-electric power technologically feasible. Such plants would be similar to hydro-electric plants and would have

G. S. Bisnovatyi-Kogan, N. V. Pogorelov

We study axisymmetric accretion of slowly rotating matter onto a gravitation center. The process of the flow restructuring is presented as the angular velocity of accreting gas approaches the Keplerian velocity. For spherically-symmetric accretion we found conditions of existence of steady-state supersonic solutions for various external boundary conditions.

Jishnu Dey, Mira Dey, Mahendra Sinha Roy

We support the idea that the baryon, B with mass $M_B$, couples to its current with a coupling $\la_{B}^2 \sim 0.71 M_B^6$ from an analysis of magnetic moment sum rules. And we find a sum rule among the experimental magnetic moments which is independent of the parameters of QCDSR.

Yasunori Fujii, Akira Iwamoto, Tokio Fukahori, Toshihiko Ohnuki

We re-examine the effort to constrain the time-variability of the coupling constants of the fundamental interactions by studying the anomalous isotopic abundance of Sm observed at the remnants of the natural reactors which were in operation at Oklo about 2 billion years ago, in terms of a possible deviation of the resonance energy from the value observed tod

Yoshio Koide

On the universal seesaw mass matrix model, which is a promising model of the unified description of the quark and lepton mass matrices, the behaviors of the gauge coupling constants and intermediate energy scales in the SO(10)_L\times SO(10)_R model are investigated related to the neutrino mass generation scenarios. The unification of the gauge coupling cons

C. P. Sun, S. X. Yu, Y. B. Gao

The Gardiner&#39;s phonon presented for a particle-number conserving approximation method to describe the dynamics of Bose-Einstein Condesation (BEC) (C.W. Gardiner, Phys. Rev. A 56, 1414 (1997)) is shown to be a physical realization of the $q$-deformed boson, which was abstractly developed in quantum group theory. On this observation, the coherent output of

M. Rakhmanov, A. Arodzero

The dynamics of Fabry-Perot cavity with suspended mirrors is described. The suspended mirrors are nonlinear oscillators interacting with each other through the laser circulating in the cavity. The degrees of freedom decouple in normal coordinates, which are the position of the center of mass and the length of the cavity. We introduce two parameters and study

S. I. Bityukov, N. V. Krasnikov

Several statistics used by physicists to declare the signal observability over the background are compared. It is shown that the frequentist method of testing a precise hypothesis allows one to estimate the power value of criteria with specified level of significance for the considered statistics by Monte Carlo calculations. The application of this approach

A. Dimakis, F. Muller-Hoissen

We introduce a Hodge operator in a framework of noncommutative geometry. The complete integrability of 2-dimensional classical harmonic maps into groups (sigma-models or principal chiral models) is then extended to a class of &#39;noncommutative&#39; harmonic maps into matrix algebras.

Justin R. Smith

This paper proves that the functor $C(*)$ that sends pointed, simply-connected CW-complexes to their chain-complexes equipped with diagonals and iterated higher diagonals, determines their integral homotopy type --- even inducing an equivalence of categories between the category of CW-complexes up to homotopy equivalence and a certain category of chain-compl

Minhyong Kim

We prove a new bound for the Arakelov-Faltings height of an abelian variety over a function field of characteristic zero and relate it to inequalities of ABC-type as conjectured by Buium and Vojta.

Debajyoti Choudhury, Anindya Datta, Sreerup Raychaudhuri

At the Fermilab Tevatron, final states with three tagged b-jets could play an important role in searches for a Higgs boson with mass in the range 100-300 GeV. These signals arise from gb fusion and we demonstrate their observability in the limit of a large b-quark Yukawa coupling. Rather promising discovery limits on such a coupling are obtained and conseque

Eric Laenen, Sven-Olaf Moch

We present the threshold resummation for the cross section for electroproduction of heavy quarks. We work to next-to-leading logarithmic accuracy, and in single-particle inclusive kinematics. We provide next-to-leading and next-to-next-to-leading order expansions of our resummed formula, and examine numerically the quality of these finite order approximation

Utpal Sarkar

During a large period of time, the anomalous baryon number violating interactions are in equilibrium, when the $(B+L)$ asymmetry is washed out. If there is any lepton number violation during this period, that will also erase the $(B-L)$ asymmetry. As a result, survival of the baryon asymmetry of the universe pose strong constraints on lepton number violating

K. Hornbostel, in collaboration with, :, C. T. H. Davies

We present new values for the $\bar{MS}$ masses of $b$ and $c$ quarks based on lattice NRQCD simulations of the $Υ(b\bar{b})$ and $ψ(c\bar{c})$ systems. These include three measurements of the $b$ mass based on quenched simulations with lattice spacings ranging from 0.05fm to 0.15fm, which we find to be largely independent of lattice spacing. In addition, we

David Eppstein

We show that any polyhedron forming a topological ball with an even number of quadrilateral sides can be partitioned into O(n) topological cubes, meeting face to face. The result generalizes to non-simply-connected polyhedra satisfying an additional bipartiteness condition. The same techniques can also be used to reduce the geometric version of the hexahedra

Jose M. Vidal, Edmund H. Durfee

We present our approach to the problem of how an agent, within an economic Multi-Agent System, can determine when it should behave strategically (i.e. learn and use models of other agents), and when it should act as a simple price-taker. We provide a framework for the incremental implementation of modeling capabilities in agents, and a description of the for

A. S. Yeh, H. L. Stormer, D. C. Tsui, L. N. Pfeiffer

We investigate the properties of composite fermions with four attached flux quanta through tilted field experiments near Landau level filling factor nu = 3/4. The observed collapse of fractional quantum Hall gaps in the vicinity of this quarter-filling state can be comprehensively understood in terms of composite fermions with mass and spin. Remarkably, the

Adrienne M. Cool, Jonathan E. Grindlay, Haldan N. Cohn, Phyllis N. Lugger

We present evidence that the globular cluster NGC 6397 contains two distinct classes of centrally-concentrated UV-bright stars. Color-magnitude diagrams constructed from U, B, V, and I data obtained with the HST/WFPC2 reveal seven UV-bright stars fainter than the main-sequence turnoff, three of which had previously been identified as cataclysmic variables (C

H. J. Haubold

In 1990, the United Nations, in cooperation with the European Space Agency, initiated the organization of a series of annual Workshops on Basic Space Science for the benefit of astronomers and space scientists in Asia and the Pacific, Latin American and the Caribbean, Africa, Western Asia, and Europe. This article summarizes accomplishments of these Workshop

J. Wagenhuber, M. A. T. Groenewegen

Analytic formulae are presented to construct detailed secular lightcurves of both early asymptotic giant branch (AGB) and thermally pulsing AGB stars. They are based on an extensive grid of evolutionary calculations, performed with an updated stellar evolution code. Basic input parameters are the initial mass between 0.8 and 7 solar mass, metallicity of 0.00

Mark Srednicki

We consider many-body quantum systems that exhibit quantum chaos, in the sense that the observables of interest act on energy eigenstates like banded random matrices. We study the time-dependent expectation values of these observables, assuming that the system is in a definite (but arbitrary) pure quantum state. We induce a probability distribution for the e

A. N. Cillis, H. Fanchiotti, C. A. Garcia Canal, S. J. Sciutto

An analysis of the influence of the Landau-Migdal-Pomeranchuk (LPM) effect on the development of air showers initiated by astroparticles is presented. The theory of Migdal is studied and compared with other theoretical methods, particularly the Blankenbecler and Drell approach. By means of realistic computer simulations and using algorithms that emulate Migd

Paul J. Werbos

Classical adaptive control proves total-system stability for control of linear plants, but only for plants meeting very restrictive assumptions. Approximate Dynamic Programming (ADP) has the potential, in principle, to ensure stability without such tight restrictions. It also offers nonlinear and neural extensions for optimal control, with empirically suppor

M. C. Gonzalez-Garcia, M. M. Guzzo, P. I. Krastev, H. Nunokawa

Flavor changing (FC) neutrino-matter interactions can account for the zenith-angle dependent deficit of atmospheric neutrinos observed in the SuperKamiokande experiment, without directly invoking neither neutrino mass, nor mixing. We find that FC $ν_μ$-matter interactions provide a good fit to the observed zenith angle distributions, comparable in quality to

Jonathan L. Rosner

Some interesting heavy-flavor questions are mentioned that may yield to the methods of lattice QCD. Special emphasis is placed on topics which arise in the discussion of CP violation in $B$ decays. Other subjects include quarkonium and light-quark systems and some potential applications outside QCD.

Christof Gattringer

The hopping expansion of 8-vertex models in their Grassmann representation is studied. We use the functional similarity of the Ising model in this expansion with the hopping expansion of 2-D Wilson fermions to show that the lattice fermions are equivalent to the Self-avoiding Loop Model at bending rigidity 1/sqrt{2}.

Alain Karma, Mathis Plapp

Spiral surface growth is well understood in the limit where the step motion is controlled by the local supersaturation of adatoms near the spiral ridge. In epitaxial thin-film growth, however, spirals can form in a step-flow regime where desorption of adatoms is negligible and the ridge dynamics is governed by the non-local diffusion field of adatoms on the

Alekhin Sergey

We performed NLO QCD analysis of the nonsinglet part of the combined SLAC/BCDMS data on $F_2$ with the extraction of $α_s$ and high twist contribution. It was shown that the value of $α_s$ obtained in the analysis is sensitive to the statistical inference procedures dealing with systematic errors on the data. The fit with the complete account of point-to-poi

Jack Boyce, Raymond Y. Chiao

A new type of transverse instability in dispersively nonlinear optical cavities, called the optical whistle, is discussed. This instability occurs in the mean-field, soliton forming limit when the cavity is driven with a finite-width Gaussian beam, and gives rise to oscillation, period doubling, and chaos. It is also seen that bistability is strongly affecte

Nam-Jung Kim, Dragana Popovic, S. Washburn

We explore the scaling description for a two-dimensional metal-insulator transition (MIT) of electrons in silicon. Near the MIT, $β_{T}/p = (-1/p)d(\ln g)/d(\ln T)$ is universal (with $p$, a sample dependent exponent, determined separately; $g$--conductance, $T$--temperature). We obtain the characteristic temperatures $T_0$ and $T_1$ demarking respectively t

Dimitrios Psaltis, Deepto Chakrabarty

The recent discovery of the first known accretion-powered millisecond pulsar with the Rossi X-Ray Timing Explorer provides the first direct probe of the interaction of an accretion disk with the magnetic field of a weakly magnetic (B<10^10 G) neutron star. We demonstrate that the presence of coherent pulsations from a weakly magnetic neutron star over a wide

E. V. Kuraev, N. N. Nikolaev, B. G. Zakharov

We derive a full set, and determine the twist, of helicity amplitudes for diffractive production of light to heavy vector mesons in deep inelastic scattering. For large $Q^{2}$ all helicity amplitudes but the double-flip are calculable in perturbative QCD and are proportional to the gluon structure function of the proton at a similar hard scale. We find a su

F. Chishtie, V. Elias, T. G. Steele

Within the context of massive N-component $ϕ^4$ scalar field theory, we use asymptotic Pade-approximant methods to estimate from prior orders of perturbation theory the five-loop contributions to the coupling-constant beta-function $β_g$, the anomalous mass dimension $γ_m$, the vacuum-energy beta-function $β_v$, and the anomalous dimension $γ_2$ of the scala

Antal Károlyi, János Kertész, Shlomo Havlin, Hernán A. Makse

We study the filling process of a two-dimensional silo with inelastic particles by simulation of a granular media lattice gas (GMLG) model. We calculate the surface shape and flow profiles for a monodisperse system and we introduce a novel generalization of the GMLG model for a binary mixture of particles of different friction properties where, for the first

D. P. Menezes, C. Providencia

An extended version of the non linear Walecka model, with rho mesons and eletromagnetic field is used to investigate the possibility of phase transitions in hot (warm) nuclear matter, giving rise to droplet formation. Surface properties of asymmetric nuclear matter as the droplet surface energy and its thickness are also examined.

H. Heiselberg

The nuclear overlap zone in non-central relativistic heavy ion collisions is azimuthally very asymmetric. By varying the angle between the axes of deformation and the transverse direction of the pair momenta, the transverse HBT radii oscillate in a characteristic way. It is shown that these oscillations allow determination of source sizes, deformations as we

Yuji Ohta

Differential equations for scaling relation of prepotential in N=2 supersymmetric SU(2) Yang-Mills theory coupled with massive matter hypermultiplet are proposed and are explicitly demonstrated in one flavour ($N_f =1$) theory. By applying Whitham dynamics, the first order derivative of the prepotential over the $T_0$ variable corresponding to the mass of th

Max Tegmark, Benjamin C. Bromley

We show that the galaxy density in the Las Campanas Redshift Survey (LCRS) cannot be perfectly correlated with the underlying mass distribution since various galaxy subpopulations are not perfectly correlated with each other, even taking shot noise into account. This rules out the hypothesis of simple linear biasing, and suggests that the recently proposed s

Ariel Caticha

Entropic arguments are shown to play a central role in the foundations of quantum theory. We prove that probabilities are given by the modulus squared of wave functions, and that the time evolution of states is linear and also unitary.

K. Langanke, G. Martinez-Pinedo

At densities between 10^8 and 10^10} g/cm^3 electron capture in a presupernova collapse is believed to mainly occur on odd-odd nuclei. We have derived the rates for six of the most important electron capturing nuclei, {54,56,58}Mn and {56,58,60}Co, based on calculations of the Gamow-Teller strength distributions for the ground states and first excited states

K. Langanke, G. Martinez-Pinedo

We have calculated the Gamow-Teller strength distributions for the ground states and first excited states in 55Co and 56Ni. These calculations have been performed by shell model diagonalization in the pf shell using the KB3 interaction. The Gamow-Teller distributions are used to calculate the electron capture rates for typical presupernova conditions. Our 55

G. Fabbri, M. Colonna, M. Di Toro

In this paper we discuss the reaction mechanisms that occur in the overlap zone for semi-peripheral heavy ion collisions at intermediate energies. In particular we focus on the development of neck instabilities, that could determine a possible increase of dynamical fluctuations. As observed in recent experimental data, at beam energies just above 10 MeV/A th

J. Borg, I. N. Mishustin, J. P. Bondorf

We study the nuclear liquid-gas phase transition on the basis of a two-component lattice gas model. A Metropolis type of sampling method is used to generate microscopic states in the canonical ensemble. The effective equation of state and fragment mass distributions are evaluated in a wide range of temperatures and densities. A definition of the phase coexis

S. Kudla, M. Rapoport

We establish a relation between intersection numbers of special cycles on a Shimura curve and special values of derivatives of metaplectic Eisenstein series at a place of bad reduction where p-adic uniformization in the sense of Cherednik and Drinfeld holds. The result extends the one established by one of us (S. Kudla: Ann. of Math. 146 (1997)) for the arch

Riccardo Benedetti, Carlo Petronio

We extend Turaev&#39;s definition of torsion invariants of 3-dimensional manifolds equipped with non-singular vector fields, by allowing (suitable) tangency circles to the boundary, and manifolds with non-zero Euler characteristic. We show that these invariants apply in particular to (the exterior of) Legendrian links in contact 3-manifolds. Our approach use

Sadayoshi Kojima, Haruko Nishi, Yasushi Yamashita

A purely combinatorial compactification of the configuration space of n (>4) distinct points with equal weights in the real projective line was introduced by M. Yoshida. We geometrize it so that it will be a real hyperbolic cone-manifold of finite volume with dimension n-3. Then, we vary weights for points. The geometrization still makes sense and yields a d

David Berenstein, Richard Corrado, Willy Fischler, Juan Maldacena

The operator product expansion for ``small&#39;&#39; Wilson loops in {\cal N}=4, d=4 SYM is studied. The OPE coefficients are calculated in the large N and g_{YM}^2 N limit by exploiting the AdS/CFT correspondence. We also consider Wilson surfaces in the (0,2), d=6 superconformal theory. In this case, we find that the UV divergent terms include a term propor

Rajesh Gopakumar, Cumrun Vafa

The $R^2 F^{2g-2}$ terms of Type IIA strings on Calabi-Yau 3-folds, which are given by the corresponding topological string amplitudes (a worldsheet instanton sum for all genera), are shown to have a simple M-theory interpretation. In particular, a Schwinger one-loop computation in M-theory with wrapped M2 branes and Kaluza-Klein modes going around the loop

V. I. Tkach, J. J. Rosales, J. Torres

In this article we consider the local supersymmetry breaking and the broken SU(5) symmetry permisible by dilaton vacuum configuration in supergravity theories. We establish the parameter relation of spontaneuos breaking of supersymmetry and of the GUT theory.

Massimo Giovannini

The inhomogeneities associated with massless Kalb-Ramond axions can be amplified not only in isotropic (four-dimensional) string cosmological models but also in the fully anisotropic case. If the background geometry is isotropic, the axions (which are not part of the homogeneous background) develop, outside the horizon, growing modes leading, ultimately, to

M. Shifman

In the (non-supersymmetric) Yang-Mills theory in the large N limit there exists an infinite set of non-degenerate vacua. The distinct vacua are separated by domain walls whose tension determines the decay rate of the false vacua. I discuss the phenomenon from a field-theoretic point of view, starting from supersymmetric gluodynamics and then breaking supersy

M. N. Chernodub, D. A. Komarov

A dual Ginzburg-Landau model corresponding to SU(3) gluodynamics in abelian projection is studied. A string theory describing QCD string dynamics is obtained in this model. The interaction of static quarks in mesons and baryons is investigated in an approximation to leading order.

S. Ansoldi, C. Castro, E. Spallucci

We recover a general representation for the quantum state of a relativistic closed line (loop) in terms of string degrees of freedom.The general form of the loop functional splits into the product of the Eguchi functional, encoding the holographic quantum dynamics, times the Polyakov path integral, taking into account the full Bulk dynamics, times a loop eff

Jiro Hashiba

We show that the brane configuration describing the Izawa-Yanagida-Intriligator-Thomas (IYIT) model with gauged U(1) subgroup of the global symmetry contains inconsistent geometry, implying that there exists a stable vacuum where supersymmetry is dynamically broken.

Jonathan A. Bagger, Richard Altendorfer

In this talk we will study the partial breaking of supersymmetry in flat and anti de Sitter space. We will see that partial breaking in flat space can be accomplished using either of two representations for the massive N=1 spin-3/2 multiplet. We will &#34;unHiggs&#34; each representation and find a new N=2 supergravity and a new N=2 supersymmetry algebra. We

D. V. Nanopoulos

Cryptons, metastable bound states of matter in the string hidden sector, with dynamically determined masses M_X on the order of 10^{12} GeV and lifetimes tau_X greater than or on the order of 10^{18} yr, may be generated, through inflation, with an abundance close to that required for a near-critical universe. Their decay debris may be responsible for the mo