January 2000 arXiv papers — page 18

X. Barcons, F. J. Carrera, M. T. Ceballos, S. Mateos

In this paper we discuss various possibilities of using X-ray observations to gain information about the large-scale structure of the Universe. After reviewing briefly the current status of these investigations we explore different ways of making progress in this field, using deep surveys, large area surveys and X-ray background observations.

J. D. Vergados

The detection of the theoretically expected dark matter is central to particle physics cosmology. Current fashionable supersymmetric models provide a natural dark matter candidate which is the lightest supersymmetric particle (LSP). Such models combined with fairly well understood physics like the quark substructure of the nucleon and the nuclear form factor

Margarita Hernanz, Jordi Jose

The mechanism of classical novae explosions is explained, together with some of their observational properties. The scarce but not null impact of novae in the chemical evolution of the Milky Way is analyzed, as well as their relevance for the radioactivity in the Galaxy. A special emphasis is given to the predicted gamma-ray emission from novae and its relat

E. Athanassoula

In this paper I focus on three topics related to the dynamical evolution of small galaxy groups, for which the input of N-body simulations has been decisive. These are the merging rates in compact groups, the properties of remnants of multiple mergers, and the evolution of disc galaxies surrounded by one or more satellites. The short dynamical times of compa

A. M. Atoyan, R. J. Tuffs, F. A. Aharonian, H. J. Voelk

We consider the effect of energy dependent propagation of relativistic electrons in a spatially inhomogeneous medium in order to interpret the broad-band nonthermal radiation of the young supernova remnant (SNR) Cassiopeia A. A two-zone model is proposed that distinguishes between compact, bright steep-spectrum radio knots and the bright fragmented radio rin

A. M. Atoyan, F. A. Aharonian, R. J. Tuffs, H. J. Voelk

Based on the results of our previous study of the broad band synchrotron emission of Cas A in the framework of a spatial inhomogeneous model, we calculate the fluxes of gamma-radiation that can be expected from this supernova remnant in different energy bands. We show that at energies below 10 GeV gamma-ray fluxes detectable by forthcoming space-borne detect

F. Yusef-Zade, F. Melia, M. Wardle

The region bounded by the inner tens of light years at the center of the Milky Way contains five principal components that coexist within the central deep gravitational potential well. These constituents are a black hole candidate (Sgr~A*) with a mass equivalent to $2.6\pm0.2\times 10^6$ suns, a surrounding cluster of evolved stars, a complex of young stars,

Vaggelis Kolokotronis, Spyros Basilakos, Manolis Plionis, Ioannis Georgantopoulos

We present a detailed study of the morphological features of 22 rich galaxy clusters. We systematically compare cluster images and morphological parameters in an attempt to reliably identify possible substructure in both optical and X-ray images. To this end, we compute moments of the surface-brightness distribution to estimate ellipticities, center-of-mass

K. Beuermann, P. Wheatley, G. Ramsay, F. Euchner

Low-state spectrophotometry of the short-period polar EF Eridani (Porb=81 min) found the system at V=18.0 with no trace of the companion (Wheatley and Ramsay 1998). We show that the lack of such spectral features implies that the companion to the white dwarf in EF Eri has a spectral type later than M9 and is either a transition object at the brink of hydroge

X. Barcons, F. J. Carrera, M. T. Ceballos, S. Mateos

We review the current status of studies of large-scale structure in the X-ray Universe. After motivating the use X-rays for cosmological purposes, we discuss the various approaches used on different angular scales including X-ray background multipoles, cross-correlations of the X-ray background with galaxy catalogues, clustering of X-ray selected sources and

Janusz Gil, David Khechinashvili, George Melikidze

We present a model for generation mechanisms of the optical pulsations recently detected from the Geminga pulsar. We argue that this is just a synchrotron radiation emitted along open magnetic field lines at altitudes of a few light cylinder radii (which requires that Geminga is an almost aligned rotator), where charged particles acquire non-zero pitch-angle

Simon Goodwin, Frazer Pearce, Peter Thomas

The Hydra $N$-body hydrodynamics code has been modified to model, from the end of the Sedov phase, the effects of supernovae on the surrounding medium. The motivation is to investigate the feedback of energy into the interstellar/intergalactic medium. We compare our results for supernova remnants (SNRs) in a uniform medium to previous detailed work on the la

A. J. Blair, G. C. Stewart, I. Georgantopoulos, B. J. Boyle

Using a sample of 165 X-ray selected QSOs from seven deep ROSAT fields we investigate the X-ray spectral properties of an ``average&#39;&#39;radio-quiet broad line QSO as a function of redshift. The QSO stacked spectra, in the observers 0.1-2 keV band, in five redshift bins over the range 0.1<z<3.2 apparently harden from an equivalent photon index of 2.6 at

A. C. Fabian

The total energy emitted by the growth of massive black holes is large and can be 10-50 per cent of that emitted by stars in the universe. I show how the X-ray Background provides a good measure of this energy and also why most accretion power is absorbed and re-emitted in the far infrared band. A model for the obscured growth of massive black holes is prese

Laurance R. Doyle, Hans J. Deeg, Valerij P. Kozhevnikov, Brian Oetiker

A lightcurve of the eclipsing binary CM Draconis has been analyzed for the presence of transits of planets of size >= 2.5 Earth-radii (Re), with periods of 60 days or less, and in co-planar orbits around the binary system. About 400 million model lightcurves, representing transits from planets with periods ranging from 7 to 60 days, have been matched/correla

A. C. Fabian

The role of X-ray observations for cosmological studies and conclusions is briefly explored. X-rays currently yield cosmologically interesting results on the abundances, evolution and gas content of clusters of galaxies, on the clustering and evolution of active galaxies and on the X-ray Background. They are unlikely in the long term future to give the most

Jose F. Gomez, Joaquin Trapero, Sergio Pascual, Nimesh Patel

We present NH3(1,1) and NH3(2,2) observations of MBM 12, the closest known molecular cloud (65 pc distance), aimed to find evidence for on-going star formation processes. No local temperature (with a T_rot upper limit of 12 K) nor linewidth enhancement is found, which suggests that the area of the cloud we mapped (~ 15&#39; size) is not currently forming sta

Naoyuki Tamura, Chiaki Kobayashi, Nobuo Arimoto, Tadayuki Kodama

The origin of color gradients in elliptical galaxies is examined by comparing model gradients with those observed in the Hubble Deep Field. The models are constructed so as to reproduce color gradients in local elliptical galaxies either by a metallicity gradient or by an age gradient. By looking back a sequence of color gradient as a function of redshift, t

S. Garcia-Burillo, J. Martin-Pintado, A. Fuente, R. Neri

This paper presents the first high-resolution SiO map made in an external galaxy. The nucleus of the nearby barred spiral NGC253 has been observed simultaneously in the v=0, J=2-1 line of SiO and in the J=1-0 line of H13CO+ with the IRAM interferometer, with a resolution of 7.5&#34;x2.6&#34;. Emission from SiO and H13CO+ is extended in the nucleus of NGC253.

M. A. Barstow, S. Dreizler, J. B. Holberg, D. S. Finley

We present the first evidence for the direct detection of nickel in the photosphere of the hot DO white dwarf REJ0503$-$289. While this element has been seen previously in the atmospheres of hot H-rich white dwarfs, this is one of the first similar discoveries in a He-rich object. Intriguingly, iron, which is observed to be more abundant than Ni in the hot D

Donald F. Figer, E. E. Becklin, Ian S. McLean, Andrea M. Gilbert

We present moderate (R~$\approx$~2,700) and high resolution (R~$\approx$~22,000) 2.0$-$2.4 \micron\ spectroscopy of the central 0.1 square arcseconds of the Galaxy obtained with NIRSPEC, the facility near-infrared spectrometer for the Keck II telescope. The composite spectra do not have any features attributable to the brightest stars in the central cluster,

G. Meynet, M. Arnould

Meynet and Arnould (1993) have suggested that Wolf-Rayet (WR) stars could significantly contaminate the Galaxy with 19F. In their scenario, 19F is synthesized at the beginning of the He-burning phase from the 14N left over by the previous CNO-burning core, and is ejected in the interstellar medium when the star enters its WC phase. Recourse to CNO seeds make

Hajime Susa, Masayuki Umemura

The pancake collapse of pregalactic clouds under UV background radiation is explored with a one-dimensional sheet model. Here, attention is concentrated on elucidating the basic physics on the thermal evolution of pregalactic clouds exposed to diffuse UV radiation. So, we treat accurately the radiation transfer for the ionizing photons, with solving chemical

Xinwu Cao

The apparent position angle difference $Δ$PA between parsec and kilo-parsec jets in blazars can be related to the bending properties of the jets. We present correlations between the misalignment $Δ$PA and the ratio of radio to broad-line emission for a sample of $γ$-ray blazars. The present study is limited to EGRET sources due to uniform data for the radio

M. van der Klis

The first millisecond X-ray variability phenomena from accreting compact objects have recently been discovered with the Rossi X-ray Timing Explorer. Three new phenomena are observed from low-mass X-ray binaries containing low-magnetic-field neutron stars: millisecond pulsations, burst oscillations and kiloHertz quasi-periodic oscillations. Models for these n

L. M. Lubin, R. Brunner, M. R. Metzger, M. Postman

We present the results from a multi-band optical imaging program which has definitively confirmed the existence of a supercluster at z = 0.91. Two massive clusters of galaxies, CL1604+4304 at z = 0.897 and CL1604+4321 at z = 0.924, were originally observed in the high-redshift cluster survey of Oke, Postman & Lubin (1998). They are separated by 4300 km/s in

S. N. Zhang, Wei Cui, Wan Chen, Yangsen Yao

Modeling of the x-ray spectra of the Galactic superluminal jet sources GRS 1915+105 and GRO J1655-40 reveal a three-layered atmospheric structure in the inner region of their accretion disks. Above the cold and optically thick disk of a temperature 0.2-0.5 keV, there is a warm layer with a temperature of 1.0-1.5 keV and an optical depth around 10. Sometimes

J. Daniel Christensen, Bernhard Keller, Amnon Neeman

Let T be a triangulated category with coproducts, C the full subcategory of compact objects in T. If T is the homotopy category of spectra, Adams proved the following in [Adams71]: All contravariant homological functors C --> Ab are the restrictions of representable functors on T, and all natural transformations are the restrictions of morphisms in T. It has

Joachim Weber, Fritz Haake, Petr Seba

Resonances of the time evolution (Frobenius-Perron) operator P for phase space densities have recently been shown to play a key role for the interrelations of classical, semiclassical and quantum dynamics. Efficient methods to determine resonances are thus in demand, in particular for Hamiltonian systems displaying a mix of chaotic and regular behavior. We p

Jonathan Granot, Tsvi Piran, Re&#39;em Sari

We discuss the spectrum arising from synchrotron emission by fast cooling (FC) electrons, when fresh electrons are continually accelerated by a strong blast wave, into a power law distribution of energies. The FC spectrum was so far described by four power law segments divided by three break frequencies $ν_{sa} < ν_{c} < ν_{m}$. This is valid for a homogeneo

Juan Maldacena, Hirosi Ooguri

In this paper we study the spectrum of bosonic string theory on AdS_3. We study classical solutions of the SL(2,R) WZW model, including solutions for long strings with non-zero winding number. We show that the model has a symmetry relating string configurations with different winding numbers. We then study the Hilbert space of the WZW model, including all st

Jeroen Homan, Rudy Wijnands, Michiel van der Klis, Tomaso Belloni

We present an analysis of RXTE data of the X-ray transient XTE J1550-564. The source went through several states, which were divided into spectrally soft and hard states. These states showed up as distinct branches in the color-color diagram, forming a structure with a comb-like topology; the soft state branch forming the spine and the hard state branches fo

I. Y. Park, R. von Unge

Using the graphical method developed in hep-th/9908082, we obtain the full curve corresponding to the hyperkähler quotient from the extended E_7 Dynkin diagram. As in the E_6 case discussed in the same paper above, the resulting curve is the same as the one obtained by Minahan and Nemeschansky. Our results seem to indicate that it is possible to define a gen

Arun Paramekanti, Mohit Randeria

We argue based on theoretical considerations and analysis of experimental data that quasiparticle excitations near the nodes determine the low temperature properties in the superconducting state of cuprates. Quantum effects of phase fluctuations are shown to be quantitatively important, but thermal effects are small for $T \ll T_c$. An anisotropic superfluid

I. V. Tyutin

We present the proof of the equivalence theorem in quantum field theory which is based on a formulation of this problem in the field-antifield formalism. As an example, we consider a model in which a different choices of natural finite counterterms is possible, leading to physically non-equivalent quantum theories while the equivalent theorem remains valid.

L. Gallot, A. Lerda, P. Strigazzi

We study the gauge and gravitational interactions of the stable non-BPS D-particles of the type I string theory. The gravitational interactions are obtained using the boundary state formalism while the SO(32) gauge interactions are determined by evaluating disk diagrams with suitable insertions of boundary changing (or twist) operators. In particular the gau

Felix Finster

The &#34;principle of the fermionic projector&#34; provides a new mathematical framework for the formulation of physical theories and is a promising approach for physics beyond the standard model. The book begins with a brief review of relativity, relativistic quantum mechanics and classical gauge theories, with the emphasis on the basic physical concepts an

De-Min Li, Hong Yu, Qi-Xing Shen

The moment expressions for the boson resonances X with spin-parity 0++, 1-+, 1++, and 2++ possibly produced in the process $J/ψ\toρX$, $X\to b_1(1235)π$, $b_1\to ωπ$ are given in terms of the generalized moment analysis method. The 1-+ resonance can be distinguished from other resonances by means of these moments except for some rather special cases. The sug

Thibault Damour, Bala R. Iyer, B. S. Sathyaprakash

Frequency-domain filters for time-windowed gravitational waves from inspiralling compact binaries are constructed which combine the excellent performance of our previously developed time-domain P-approximants with the analytic convenience of the stationary phase approximation without a serious loss in event rate. These Fourier-domain representations incorpor

Takayuki Tamura, Kazuo Makishima, Yasushi Fukazawa, Yasushi Ikebe

X-ray spectral and imaging data from ASCA and ROSAT were used to measure the total mass profile in the central region of Abell 1060, a nearby and relatively poor cluster of galaxies. The ASCA X-ray spectra, after correcting for the spatial response of the X-ray telescope, show an isothermal distribution of the intra-cluster medium (ICM) within at least $\sim

M. Beneke, G. A. Schuler, S. Wolf

According to our present understanding many $J/ψ$ production processes proceed through a coloured $c\bar{c}$ state followed by the emission of soft particles in the quarkonium rest frame. The kinematic effect of soft particle emission is usually a higher-order effect in the non-relativistic expansion, but becomes important near the kinematic endpoint of quar

S. R. Choudhury, A. Cornell, G. C. Joshi

In this note we study an interesting effect of low energy gravity on photon-photon scattering at high energies.

Russell K. Standish

Ensemble theories have received a lot of interest recently as a means of explaining a lot of the detailed complexity observed in reality by a vastly simpler description ``every possibility exists&#39;&#39; and a selection principle ({\em Anthropic Principle}) ``we only observe that which is consistent with our existence&#39;&#39;. In this paper I show why, i

Carlos O. Nicasio, Reinaldo Gleiser, Jorge Pullin

We consider perturbations of a Schwarzschild black hole that can be of both even and odd parity, keeping terms up to second order in perturbation theory, for the $\ell=2$ axisymmetric case. We develop explicit formulae for the evolution equations and radiated energies and waveforms using the Regge-Wheeler-Zerilli approach. This formulation is useful, for ins

D. A. Trifonov

A sufficient condition for a state |ψ> to minimize the Robertson-Schrödinger uncertainty relation for two observables A and B is obtained which for A with no discrete spectrum is also a necessary one. Such states, called generalized intelligent states (GIS), exhibit arbitrarily strong squeezing (after Eberly) of A and B. Systems of GIS for the SU(1,1) and SU

B. Roy, P. Roy

We construct a displacement operator type nonlinear coherent state and examine some of its properties. In particular it is shown that this nonlinear coherent state exhibits nonclassical properties like squeezing and sub-Poissonian behaviour.

Glenn Watson, John R. Klauder

Affine variables, which have the virtue of preserving the positive-definite character of matrix-like objects, have been suggested as replacements for the canonical variables of standard quantization schemes, especially in the context of quantum gravity. We develop the kinematics of such variables, discussing suitable coherent states, their associated resolut

Partha Ghose

In spite of its popularity, it has not been possible to vindicate the conventional wisdom that classical mechanics is a limiting case of quantum mechanics. The purpose of the present paper is to offer an alternative point of view in which quantum mechanics emerges as a limiting case of classical mechanics in which the classical system is decoupled from its e

Vilen Melik-Alaverdian, M. P. Nightingale

This paper deals with the optimization of trial states for the computation of dominant eigenvalues of operators and very large matrices. In addition to preliminary results for the energy spectrum of van der Waals clusters, we review results of the application of this method to the computation of relaxation times of independent relaxation modes at the Ising c

Fan Wang, T. Goldman

The work of Yuan et al. (Phys. Rev. C 60 (1999) 045203) is being represented as definitive regarding the non-existence of a particular nonstrange, isoscalar, spin three dibaryon which has been proposed. We comment on this paper and its relation to our work and that of others.

K. Langanke, G. Martinez-Pinedo

Based on large-scale shell model calculations we have determined the electron capture, positron capture and beta-decay rates on more than 100 nuclei in the mass range A=45-65. The rates are given for densities ρY_e =10^7-10^{10} mol/cm^3 and temperatures T=10^9-10^{10} K and hence are relevant for both types of supernovae (Type Ia and Type II). The shell mod

E. Sh. Gutshabash, V. D. Lipovskii, S. S. Nikulichev

We propose a nonlinear $σ$-model in a curved space as a general integrable elliptic model. We construct its exact solutions and obtain energy estimates near the critical point. We consider the Pohlmeyer transformation in Euclidean space and investigate the gauge equivalence conditions for a broad class of elliptic equations. We develop the inverse scattering

C. Wagner

We compute the full Lyapunov spectra for a hard-disk fluid under temperature gradient and shear. The system is thermalized by deterministic and time-reversible scattering at the boundary. This thermostating mechanism allows for energy fluctuations around a mean value which is reflected by only two vanishing Lyapunov exponents in equilibrium and nonequilibriu

Yunbo Zeng

Degrees of freedom for high-order binary constrained flows of soliton equations admitting $2\times 2$ Lax matrices are $2N+k_0$. It is known that $N+k_0$ pairs of canonical separated variables for their separation of variables can be introduced directly via their Lax matrices. In present paper we propose a new method to introduce the additional $N$ pairs of

Russell K. Standish

Recently, Adami and coworkers have been able to measure the information content of digital organisms living in their {\em Avida} artificial life system. They show that over time, the organisms behave like Maxwell&#39;s demon, accreting information (or complexity) as they evolve. In {\em Avida} the organisms don&#39;t interact with each other, merely reproduc

Ron Aharoni, Eli Berger, Ran Ziv

Konig&#39;s theorem states that the covering number and the matching number of a bipartite graph are equal. We prove a generalisation of this result, in which each point in one side of the graph is replaced by a subtree of a given tree. The proof uses a recent extension of Hall&#39;s theorem to families of hypergraphs, by the first author and P. Haxell.

Keiji Oguiso, Eckart Viehweg

We study non-isotrivial projective families of elliptic surfaces of Kodaira dimension one, over complex projective curves. If the base is an elliptic curve, we show that the family must have a singular fibre, and that over the projective line it must have at least three singular fibres. Similar results, for families of surfaces of general type, have been obt

Shu-Chung Liu, Bruce Sagan

Left-modularity is a concept that generalizes modularity in lattice theory. In this paper, we give a characterization of left-modular elements and derive two formulae for the characteristic polynomial of a lattice with such an element, one of which generalizes Stanley&#39;s Partial Factorization Theorem for a geometric lattice with a modular element. Both fo

Margaret M. Bayer

A graded partially ordered set is Eulerian if every interval has the same number of elements of even rank and of odd rank. Face lattices of convex polytopes are Eulerian. For Eulerian partially ordered sets, the flag vector can be encoded efficiently in the cd-index. The cd-index of a polytope has all positive entries. An important open problem is to give th

Marco Leoni

We extend a result of to Esnault-Levine-Viehweg concerning the Chow groups of hypersurfaces in projective space to those in weighted projective spaces.

David Berenstein, Robert G. Leigh

We analyse D-branes on orbifolds with discrete torsion, extending earlier results. We analyze certain Abelian orbifolds of the type C^3/ Γ, where Γis given by Z_m x Z_n, for the most general choice of discrete torsion parameter. By comparing with the AdS/CFT correspondence, we can consider different geometries which give rise to the same physics. This identi

Oskar Pelc

Type II string theory compactified on a Calabi-Yau manifold, with a singularity modeled by a hypersurface in an orbifold, is considered. In the limit of vanishing string coupling, one expects a non gravitational theory concentrated at the singularity. It is proposed that this theory is holographicly dual to a family of ``non-critical'' superstring vacua, gen

V. I. Tkach, A. Pashnev, J. J. Rosales

We obtain a time-dependent Schrodinger equation for the Friedmann - Robertson - Walker (FRW) model interacting with a homogeneous scalar matter field. We show that for this purpose it is necesary to include an additional action invariant under the reparametrization of time. The last one does not change the equations of motion of the system, but changes only

Yuri Makeenko

Four pedagogical Lectures at the NATO-ASI on &#34;Quantum Geometry&#34; in Akureyri, Iceland, August 1999. Contents: 1. O(N) Vector Models, 2. Large-N QCD, 3. QCD in Loop Space, 4. Large-N Reduction

Horace Crater, Luca Lusanna

In the semiclassical approximation in which the electric charges of scalar particles are described by Grassmann variables ($Q_i^2=0, Q_iQ_j\ne 0$), it is possible to re-express the Lienard-Wiechert potentials and electric fields in the radiation gauge as phase space functions, because the difference among retarded, advanced, and symmetric Green functions is

O. Kenneth, S. Nussinov

We argue that the exactly computable, angle dependent, Casimir force between parallel plates with different directions of conductivity can be measured.

Y. Matsuo

We discuss tachyon configuration for the unoriented bosonic string theory which produces a bosonic string theory with SO(32) gauge symmetry in ten dimensions. It is closely related to the tachyon condensation scenario proposed by A. Sen. We also give the boundary state description of the tachyon condensation process, with some emphasis on the rôle of orbifol

Zhiyong Wang, Ailin Zhang

In this paper, we put forth a new massive spin-1 field theory. In contrast to the quantization of traditional vector field, the quantization of the new vector field is carried out in a natural way. The Lorentz invariance of the theory is discussed, where owing to an interesting feature of the new vector field, the Lorentz invariance has a special meaning. In

St. D. Glazek

We describe key elements of the perturbative similarity renormalization group procedure for Hamiltonians using two, third-order examples: phi^3 interaction term in the Hamiltonian of scalar field theory in 6 dimensions and triple-gluon vertex counterterm in the Hamiltonian of QCD in 4 dimensions. These examples provide insight into asymptotic freedom in Hami

Yu. A. Simonov, J. A. Tjon

The effective quark Lagrangian is written for a light quark in the field of a static antiquark, explicitly containing field correlators as coefficient functions of products of quark operators. At large N_c the closed system of equations for the gauge-invariant quark Green&#39;s function in the field of static source is examined analytically. The formation of

Stephen Godfrey, Pat Kalyniak, Basim Kamal, Arnd Leike

We examine the sensitivity of the process e+e- -> nu nubar gamma to extra gauge bosons, Z&#39; and W&#39;, which arise in various extensions of the standard model. The process is found to be sensitive to W&#39; masses up to several TeV, depending on the model, the center of mass energy, and the assumed integrated luminosity. If extra gauge bosons were discov

Lisa Everett, Paul Langacker, Michael Plumacher, Jing Wang

We describe the features of supersymmetric spectra, alternative to and qualitatively different from that of most versions of the MSSM. The spectra are motivated by extensions of the MSSM with an extra U(1)&#39; gauge symmetry, expected in many grand unified and superstring models, which provide a plausible solution to the mu problem, both for models with sup

G. Dvali, M. Shifman

We propose a new mechanism for explanation of the fermion hierarchy without introducing any family symmetries. Instead, we postulate that different generations live on different branes embedded in a relatively large extra dimension, where the gauge fields can propagate. The electroweak symmetry is broken on a separate brane, which is a source of exponentiall

Paolo Gondolo, Katherine Freese

We summarize our paper hep-ph/9908390, where we find that in some regions of supersymmetric parameter space, CP violating effects that mix the CP-even and CP-odd Higgs bosons can enhance the neutralino annihilation rate by factors of 10^6, and reduce the neutralino scattering rate off nucleons by factors of 10^{-7}.

Paolo Gondolo, Joseph Silk

Particle dark matter near the galactic center is accreted by the central black hole into a dense spike, strongly enhancing its annihilation rate. Searching for its annihilation products may give us information on the presence or absence of a central cusp in the dark halo profile. We summarize our paper Phys Rev Lett 83, 1719 (1999), and use an updated limit

H. Athar, Jose F. Nieves

When neutrinos propagate in a background, their gravitational couplings are modified by their weak interactions with the particles in the background. In a medium that contains electrons but no muons or taons, the matter-induced gravitational couplings of neutrinos are different for the various neutrino flavors, and they must be taken into account in describi

S. B. Gerasimov

Relativistic potential-type equations are proposed which approximately reproduce important features and constraints of field-theoretic models and can be useful tool in hadron spectroscopy. Within this approach, the Regge-trajectory parameters and some properties of hihger radial excitations in the light quark sector are discussed.

Jose F. Nieves

In a medium that contains a neutrino background in addition to the matter particles, the neutrinos contribute to the photon self-energy as a result of the effective electromagnetic vertex that they acquire in the presence of matter. We calculate the contribution to the photon self-energy in a dense plasma, due to the presence of a gas of charged particles, o

Ulf-G. Meißner

I review the novel results and developments presented at the Third Workshop on Physics and Detectors for DA$Φ$NE that deal with hadronic physics. Topics discussed include: the scalar quark condensate, kaon decays, the sector of scalar and vector mesons, kaon-nucleon scattering, pion- and kaon-nucleon sigma terms, and strange nuclear physics.

F. Gangemi, G. Montagna, M. Moretti, O. Nicrosini

Three studies on six-fermion production processes are presented, in which the production of an intermediate-mass Higgs boson, the top-quark physics and the analysis of possible anomalous quartic gauge couplings are considered. A Monte Carlo event generator has been developed for full electroweak tree-level calculations on six-fermion processes at the Linear

K. Melnikov, F. Nguyen, B. Valeriani, G. Venanzoni

The potential of DAPHNE to explore direct radiative decay $ϕ\to π^+ π^- γ$ is studied in detail. Predictions of different theoretical models for this decay are compared. We find that it should be possible to discriminate between these models at DAPHNE in one year, even assuming a relatively low luminosity ${\cal{L}} = 10^{31} {\rm cm}^{-2} {\rm sec^{-1}}$. T

CDF Collaboration, T. Affolder

The transverse momentum and total cross section of e^+e^- pairs in the Z-boson region of 66<M_{ee}<116 GeV$/c^2$ from $p\bar{p}$ collisions at $\sqrt{s}=1.8$ TeV are measured using 110 pb^{-1} of collisions taken by the Collider Detector at Fermilab during 1992-1995. The total cross section is measured to be $248 \pm 11$ pb. The differential transverse momen

G. Grindhammer, S. Peters

A general approach to a fast simulation of electromagnetic showers using parameterizations of the longitudinal and radial profiles in homogeneous and sampling calorimeters is described. The dependence of the shower development on the materials used and the sampling geometry is taken into account explicitly. Comparisons with detailed simulations of various ca

V. V. Flambaum, J. C. Berengut

It is believed that there may have been a large number of black holes formed in the very early universe. These would have quantised masses. A charged ``elementary black hole&#39;&#39; (with the minimum possible mass) can capture electrons, protons and other charged particles to form a ``black hole atom&#39;&#39;. We find the spectrum of such an object with a

Hiromi Saida, Jiro Soda

For the BTZ black hole in the Einstein gravity, a statistical entropy has been calculated. It is equal to the Bekenstein-Hawking entropy. In this article, its statistical entropy in the higer curvature gravity is calculated and shown to be equal to one derived by using the Noether charge method. This suggests that the equivalence between the geometrical and

Dominic Mayers

The paper was retracted.

Stefaan De Cnodder, Omar Elloumi, Kenny Pauwels

We consider the adaptation of random early detection (RED) as a buffer management algorithm for TCP traffic in Internet gateways where different maximum transfer units (MTUs) are used. We studied the two RED variants described in [4] and point out a weakness in both. The first variant where drop probability is independent from the packet size discriminates c

P. Kumar, Donavan Hall, R. G. Goodrich

This comment addresses criticisms of our PRL 82 (1999) p. 4532-4535 (cond-mat/9904288) raised by Woodfield et al. in their recent PRL. We find that the critical fields in single crystals of Ba1-xKxBiO3 (x = 0.4) have anomalous temperature dependecies which suggests that the superconducting phase transition in this material is not of order II.

Uwe R. Fischer

The general local, nondissipative equations of motion for a quantized vortex moving in an uncharged laboratory superfluid are derived from a relativistic, co-ordinate invariant framework, having vortices as its elementary objects in the form of stable topological excitations. This derivation is carried out for a pure superfluid with isotropic gap at the abso

Ar. Abanov, Andrey V. Chubukov

We calculate the SIN and SIS tunneling conductances for the spin-fermion model. We argue that at strong spin-fermion coupling, relevant to cuprates, both conductances have dip features near the threshold frequencies when a tunneling electron begin emitting propagating spin excitation. We argue that the resonance spin frequency measured in neutron scattering

G. D. Sanders, K. W. Kim, W. C. Holton

We investigate an optically driven quantum computer based on electric dipole transitions within coupled single-electron quantum dots. Our quantum register consists of a freestanding n-type pillar containing a series of pair wise coupled asymmetric quantum dots, each with a slightly different energy structure, and with grounding leads at the top and bottom of

M. Danckwerts A. R. Goni, C. Thomsen, K. Eberl, A. G. Rojo

An enhancement of vortex-motion damping in thin Pb/In superconducting films is obtained through coupling to an adjacent two-dimensional electron gas formed in a modulation-doped GaAs/AlGaAs heterostructure. This effect is observed by monitoring the power dissipation at the superconductor in the vortex state while increasing the density of the electron gas us

D. Loison

Classical XY spins on a two dimensional triangular lattice with antiferromagnetic interactions are reconsidered. We find that the Kosterlitz-Thouless transition associated to the U(1) symmetry appears at a temperature 0.0020(2) below the Ising transition at 0.5122(1) associated to the Z_2 symmetry. The Ising transition has critical exponents different from t

V. Melik-Alaverdian, G. Ortiz, N. E. Bonesteel

A generalized stochastic method for projecting out the ground state of the quantum many-body Schrödinger equation on curved manifolds is introduced. This random-walk method is of wide applicability to any second order differential equation (first order in time), in any spatial dimension. The technique reduces to determining the proper ``quantum corrections&#

Enrico Scalas, Rudolf Gorenflo, Francesco Mainardi

In this paper we present a rather general phenomenological theory of tick-by-tick dynamics in financial markets. Many well-known aspects, such as the Lévy scaling form, follow as particular cases of the theory. The theory fully takes into account the non-Markovian and non-local character of financial time series. Predictions on the long-time behaviour of the

V. Kurasov

The situation of the metastable phase decay on the several types of heterogeneous centers is considered. The iteration procedure is formulated and with the help of the avalanche consumption property all iterations can be calculated. The same procedure is done for the monodisperse approximation. Here the avalnche consumption is also used to calculate iteratio

Karl Strobl

We show that the frequent claim that the implied tree prices exotic options consistently with the market is untrue if the local volatilities are subject to change and the market is arbitrage-free. In the process, we analyse -- in the most general context -- the impact of stochastic variables on the P&L of a hedged portfolio, and we conclude that no model can

G. V. Shpatakovskaya

A semiclassical approach for calculating shell effects, that has been used in atomic and plasma physics, is applied to describe the electronic supershells in metal clusters. Using the spherical jellium model we give the analytical expression for the oscillating part of the binding energy of electrons as an explicit sum of contributions from supershells with

Xiaoyu Yang, D. Candela

Fast NMR imaging was used to measure the density profile of a three-dimensional granular medium fluidized by vertical vibrations of the container. For container acceleration much larger than gravity, the rise in center of mass of the granular medium is found to scale as (v0^alpha)/(N^beta) with alpha = 1.0 +/-0.2 and beta = 0.5 +/- 0.1, where v0 is the vibra

V. Kurasov

The situation of the metastable phase decay on the several types of heterogeneous centers is considered. This publication directly continues &#34; cond-mat@xxx.lanl.gov get 0001104 &#34;, &#34; cond-mat@xxx.lanl.gov get 0001108&#34; and &#34; cond-mat@xxx.lanl.gov get 0001112 &#34; . In this section the approximation od the essential asymptotes is formulated