November 2001 arXiv papers — page 10

Partha Ghose, M. K. Samal

It is shown that classical electrodynamics in its alternative Kemmer-Duffin-Petiau-Harish-Chandra formulation surprisingly reveals a Hilbert space structure leading to the possibility of entangled states of classical radiation, and this in turn implies the violation of Einstein-Bell locality in spite of Lorentz invariance.

Zhi-Jian Li, Jiu-Qing. Liang, D. H. Kobe

The Larmor precession of a relativistic neutral spin-1/2 particle in a uniform constant magnetic field confined to the region of a one-dimensional arbitrary potential barrier is investigated. The spin precession serves as a clock to measure the time spent by a quantum particle traversing a potential barrier. With the help of general spin coherent state it is

A. F. Kracklauer

A fully classical model of a recent experiment exhibiting what is interpreted as teleportation and four-photon entanglement is described. It is shown that the reason that a classical model is possible, contrary to the current belief, results ultimately from a misguided modification by Bohm of the EPR Gedanken experiment. Finally, teleportation is reinterpret

Salvatore Esposito

We report on an original method, due to Majorana, leading to a semi-analytical series solution of the Thomas-Fermi equation, with appropriate boundary conditions, in terms of only one quadrature. We also deduce a general formula for such a solution which avoids numerical integration, but is expressed in terms of the roots of a given polynomial equation.

V. Baggiolini, S. Jensen, K. Kostro, F. Di Maio

This paper presents the Remote Device Access (RDA) package developed at CERN in the framework of the joint PS/SL Controls Middleware project. The package design reflects the Accelerator Device Model in which devices, named entities in the control system, can be controlled via properties. RDA implements this model in a distributed environment with devices res

Angom Dilip Singh, Bhanu Pratap Das, Debashis Mukherjee

The existence of a finite electric dipole moment (EDM) d_a of the closed-shell atom Yb implies parity and time reversal violations involving the nuclear sector. An important effect which can contribute to the Yb EDM is the tensor-pseudotensor electron-nucleus interaction characterized by the coupling constant C_T. Within the Standard Model (SM) of particle p

A. Bertocchi, G. Buceti, C. Centioli, F. Iannone

In the last three years, the architecture of Frascati Tokamak Upgrade (FTU) experimental database has undergone meaningful modifications, data and codes have been moved from mainframe to UNIX platforms and AFS (Andrew File System) has been adopted as distributed file system. Further improvement we have added regards data storage system; the choice of SAN (St

J. T. Morris, T. S. Clifford, B. Frak, J. Laster

Reliable and reproducible performance of the more than 800 Relativistic Heavy Ion Collider (RHIC) magnet power supplies is essential to successful RHIC operation. In order to support power supply commissioning, a system was developed to capture detailed power supply measurements from all the RHIC ring power supplies during acceleration ramps. Diagnostic tool

G. R. White, H. Shoaee

We describe the software requirements and development methodology developed for the NLC control system. Given the longevity of that project, and the likely geographical distribution of the collaborating engineers, the planned requirements management process is somewhat more formal than the norm in high energy physics projects. The short term goals of the req

M. Hentschel, H. Schomerus

We discuss curvature corrections to Fresnel's laws for the reflection and transmission of light at a non-planar refractive-index boundary. The reflection coefficients are obtained from the resonances of a dielectric disk within a sequential-reflection model. The Goos-Hänchen effect for curved light fronts at a planar interface can be adapted to provide a

D. Cussol

Selected results of a classical simulation of N bodies in strong interaction are presented. The static properties of such classical systems are qualitatively similar to the known properties of atomic nuclei. The simulations of collisions show that all observed reaction mechanisms in nucleus-nucleus collisions are present in this numerical simulation. The fir

Jaivir Singh, Rajeev K. Puri, Jörg Aichelin

We report, for the first time, the dependence of the multiplicity of different fragments on the system size employing a quantum molecular dynamics model. This dependence is extracted from the simulations of symmetric collisions of Ca+Ca, Ni+Ni, Nb+Nb, Xe+Xe, Er+Er, Au+Au and U+U at incident energies between 50 A MeV and 1 A GeV. We find that the multiplicity

L. Tiator, D. Drechsel, S. Kamalov, S. N. Yang

Pion photo- and electroproduction has been studied at threshold and in the resonance region below W=2GeV. At threshold pi^0 production can be very well explained within a dynamical model derived from an effective chiral Lagrangian. The final state interaction is nearly saturated by single charge exchange rescattering. In the resonance region new electroprodu

B. T. Kim, W. Y. So, S. W. Hong, T. Udagawa

Based on an approach recently proposed by us, simultaneous $χ^{2}$-analyses are performed for elastic scattering, direct reaction (DR) and fusion cross sections data for the $^{6}$He+$^{209}$Bi system at near-Coulomb-barrier energies to determine the parameters of the polarization potential consisting of DR and fusion parts. We show that the data are well re

Vadim B. Kuznetsov

We review the separation of variables for the Kowalevski top and for its generalization to the algebra o(4). We notice that the corresponding separation equations allow an interpretation of the Kowalevski top as a B2 integrable lattice. Consequently, we apply the quadratic r-matrix formalism to construct a new 2x2 Lax matrix for the top, which is responsible

Jean-Pierre Amiet, Stefan Weigert

The symmetry properties of a classical N-dimensional harmonic oscillator with rational frequency ratios are studied from a global point of view. A commensurate oscillator possesses the same number of globally defined constants of motion as an isotropic oscillator. In both cases invariant phase-space functions form the algebra su(N) with respect to the Poisso

Semjon Vugalter, Timo Weidl

We prove Cwikel-Lieb-Rosenbljum and Lieb-Thirring type bounds on the discrete spectrum of a two-body pair operator and calculate spectral asymptotics for the eigenvalue moments and the local spectral density in the pseudo-relativistic limit.

Octavian Cornea

In a non-compact context the first natural step in the search for periodic orbits of a hamiltonian flow is to detect bounded ones. In this paper we show that, in a non-compact setting, certain algebraic topological constraints imposed to a gradient flow of the hamiltonian function $f$ imply the existence of bounded orbits for the hamiltonian flow of $f$. Onc

Jean-Christophe Aval, Nantel Bergeron

A lattice diagram is a finite list L=((p_1,q_1),...,(p_n,q_n) of lattice cells. The corresponding lattice diagram determinant is Δ_L(X;Y)=\det \| x_i^{p_j}y_i^{q_j} \|. These lattice diagram determinants are crucial in the study of the so-called ``n! conjecture'' of A. Garsia and M. Haiman. The space M_L is the space spanned by all partial derivative

Julio Rubio, Francis Sergeraert

The classical ``computation'' methods in Algebraic Topology most often work by means of highly infinite objects and in fact +are_not+ constructive. Typical examples are shown to describe the nature of the problem. The Rubio-Sergeraert solution for Constructive Algebraic Topology is recalled. This is not only a theoretical solution: the concrete compu

Oscar Bolina

We consider the classical one-dimensional random walk of a particle on the right-half real line. We assume that the particle is initially at position x=k, k > 0, and moves to the right with probability p or to the left with probability 1-p. We consider that the particle is absorbed at the origin without fixing the number of steps needed to get there. We calc

Lin Weng

Proposed is a program for what we call Geometric Arithmetic, based on our works on non-abelian zeta functions and non-abelian class field theory. Key words are stability and adelic intersection-cohomology theory.

Lin Weng

In this paper, using what we call a micro reciprocity law, we complete Weil's program for non-abelian class field theory of Riemann surfaces.

Michael K. Kinyon, Kenneth Kunen, J. D. Phillips

We study a variety of loops, RIF, which arise naturally from considering inner mapping groups, and a somewhat larger variety, ARIF. All Steiner and Moufang loops are RIF, and all flexible C-loops are ARIF. We show that all ARIF loops are diassociative, thus generalizing Moufang's Theorem.

K. Graham

In this note we consider boundary perturbations in the A-Series unitary minimal models by phi_{r,r+2} fields on superpositions of boundaries. In particular, we consider perturbations by boundary condition changing operators. Within conformal perturbation theory we explicitly map out the space of perturbative renormalisation group flows for the example phi_{1

L. Cantini, P. Menotti, D. Seminara

A proof is given of Polyakov conjecture about the auxiliary parameters of the SU(1,1) Riemann-Hilbert problem for general elliptic singularities. Such a result is related to the uniformization of the the sphere punctured by n conical defects. Its relevance to the hamiltonian structure of 2+1 dimensional gravity in the maximally slicing gauge is stressed.

Daniele Tommasini

I argue that the correlations that are predicted by Quantum Field Theory should not be interpreted as a real sign of non locality.

Marianna Larosa

Unabridged version of the Thesis presented to the University of Rome ``Tor Vergata'', in partial fulfillment of the requirements for the ``Laurea'' degree in Physics, May 2001.

Jonathan L. Feng, Konstantin T. Matchev, Frank Wilczek

Supersymmetry may be discovered at high energy colliders, through low energy precision measurements, and by dark matter searches. We present a comprehensive analysis of all available probes in minimal supergravity. This work extends previous analyses by including the focus point branch of parameter space and the full array of promising indirect dark matter s

John Ellis, Jonathan L. Feng, Andrew Ferstl, Konstantin T. Matchev

We review the prospects for discovering supersymmetric dark matter in a recently proposed set of post-LEP supersymmetric benchmark scenarios. We consider direct detection through spin-independent nuclear scattering, as well as indirect detection through relic annihilations to neutrinos, photons, and positrons. We find that several of the benchmark scenarios

M. E. Carrington, T. J. Hammond, R. Kobes

In an earlier paper Almeida and Frenkel considered the calculation of the pressure in gϕ^3 theory in 6 dimensions via the Schwinger--Dyson equation. They found, under certain approximations, that a finite result ensues in the infrared limit. We find this conclusion to remain true with certain variations of these approximations, suggesting the finiteness of t

Dmitry S. Gorbunov, Andrei V. Semenov

We present a complete description of a new physical model with goldstino supermultiplet for CompHEP software package. The model contains MSSM content supplemented by three new fields: {\it goldstino} -- two component spinor, scalar {\it sgoldstino} and pseudoscalar {\it sgoldstino}. To the leading order in 1/F, where F is the parameter of supersymmetry break

M. A. Braun, C. Merino, G. Rodriguez

Strong correlations between the number of emitted jets and their average transverse momentum are found for the events resulting from the exchange of a single BFKL pomeron. transverse momentum are found for the events resulting from the exchange.

Pierre Fayet

We discuss the possible existence of new long-range forces mediated by spin-1 or spin-0 particles. By adding their effects to those of gravity, they could lead to apparent violations of the Equivalence Principle. While the vector part in the couplings of a new spin-1 U boson involves, in general, a combination of the B and L currents, there may also be, in a

Mu-Lin Yan, Ji-Hao Jiang, Xiao-Jun Wang

Mixed Propagator (MP) approach to $ρ-ω$ mixing is discussed. It is found that under the pole-approximation assumption the results of MP approach is not compatible both with the effective Lagrangian theory and with the experiment measurement criterion. To overcome these inconsistent, we propose a new MP approach in which the physical states of $ρ$ and $ω$ are

Thomas Walcher

Several experiments suggest the existence of narrow excited states in the nucleon below the πN threshold. Taking all information together a series of states emerges at masses of 940, 966, 985, 1003, m_4, 1044, m_6, 1094 MeV above the nucleon ground state at 940 MeV with m_4 and m_6 missing. A model based on the excitation of collective states of the quark co

Lluis Ametller

The decays of the eta meson are reviewed in the framework of Chiral Perturbation Theory. Particular attention is devoted to the electromagnetic channels involving photons, either in the final or intermediate states.

T. Matsui

Lectures deliverd at the NATO Advanced Study Institute on QCD Perspectives on Hot and Dense Matter, Cargese, Aug. 6 - 18, 2001. Dedicated to the memory of Dominique Vautherin.

Yuko Fueki, Hisao Nakkagawa, Hiroshi Yokota, Koji Yoshida

In this paper we calculated the n-point hard-thermal-loop (HTL) vertex functions in QCD/QED for n= 2, 3 and 4 in the physical representation in the real time formalism (RTF). The result showed that the n-point HTL vertex functions can be classified into two groups, a) those with odd numbers of external retarded indices, and b) the others with even numbers of

Chris Quigg

Wonderful opportunities await particle physics over the next decade, with the coming of the Large Hadron Collider at CERN to explore the 1-TeV scale (extending efforts at LEP and the Tevatron to unravel the nature of electroweak symmetry breaking) and many initiatives to develop our understanding of the problem of identity: what makes a neutrino a neutrino a

B. Ananthanarayan, P. N. Pandita

Infrared fixed points in the minimal supersymmetric standard model with baryon and lepton number violation were studied and their structure elucidated by us in Physical Review D 63 076008 (2001). Here we reply to a comment on this paper. We emphasize that our paper concentrates on the case of the only true infrared fixed point in the model, i.e. the stable n

G. Calderon, G. Lopez Castro

We update the determination of |V_us| using semielectronic and semimuonic decays of K mesons. A modest improvement of 15% with respect to its present value is obtained for the error bar of this matrix element when we combine the four available semileptonic decays. The combined effects of long-distance radiative corrections and nonlinear terms in the vector f

R. Vogt

We study inclusive heavy quark and exclusive heavy quark pair production in pp, pA and AA interactions. Intrinsic transverse momentum is introduced in pp interactions. Nuclear effects, limited to $k_T$ broadening and nuclear shadowing, are introduced in pA and AA interactions. The nuclear dependence is studied over a range of energies, both in fixed target a

C. Kokorelis

We discuss supersymmetry breaking mechanisms at the level of low energy N=1 effective heterotic superstring actions that exhibit $SL(2,Z)_T$ target space modular duality or $SL(2,Z)_S$ strong-weak coupling duality. The allowed superpotential forms use the assumption that the source of non-perturbative effects is not specified and as a result represent the mo

Tereza Mendes

The chiral transition for two-flavor QCD is predicted to be in the same universality class as the 3d O(4) model. This prediction is verified in the Wilson case, but not for the staggered-fermion case. The comparison is usually done assuming infinite-volume behavior. Here we make an analysis of existing staggered-fermion data using finite-size scaling and nor

Christof Gattringer, C. B. Lang

Recently various new concepts for the construction of Dirac operators in lattice Quantum Chromodynamics (QCD) have been introduced. These operators satisfy the so-called Ginsparg-Wilson condition (GWC), thus obeying the Atiyah-Singer index theorem and violating chiral symmetry only in a modest and local form. Here we present studies in 4-d for SU(3) gauge co

V. Bornyakov, H. Ichie, S. Kitahara, Y. Koma

We present first results on the dynamics of monopoles in full QCD with N_f=2 flavors of dynamical quarks. Among the quantities being studied are the monopole density and the monopole screening length, the static potential as well as the profile of the color electric flux tube. Furthermore, we derive the low-energy effective monopole action.

Seyong Kim, Shigemi Ohta

To study continuum limit of lattice QCD with many light quark flavors, we investigate the zero temperature phase structures of multi-flavor QCD. Currently a series of exploratory simulations are being performed with the number of quark flavors, $N_f $= 6, 8, and 10 on a set of lattice volumes for various quark masses. Here, we report on the current status of

I. G. Irastorza, A. Morales, C. E. Aalseth, F. T. Avignone

One IGEX 76Ge double-beta decay detector is currently operating in the Canfranc Underground Laboratory in a search for dark matter WIMPs, through the Ge nuclear recoil produced by the WIMP elastic scattering. A new exclusion plot has been derived for WIMP-nucleon spin-independent interactions. To obtain this result, 40 days of data from the IGEX detector (en

O. Gonzalez

The internal structure of the jets produced in neutral current interactions for Q^2>125 GeV^2 has been studied using the subjet multiplicity with the ZEUS detector at HERA. Jets are identified in the laboratory frame by applying the longitudinally invariant k_T-cluster algorithm. Next-to-leading order QCD calculations have been obtained and compared to the d

V. M. Biryukov, V. N. Chepegin, Yu. A. Chesnokov, V. I. Kotov

The crystal extraction of 10^7 proton/s on BEC experiment facility is described. Detailed computer analysis is made to explain the basic experimental results. Future high-intensity efficient extraction using a short crystal is announced.

R. -D. Heuer

An electron-positron linear collider in the energy range between 500 and 1000 GeV is of crucial importance to precisely test the Standard Model and to explore the physics beyond it. The physics program is complementary to that of the Large Hadron Collider. Some of the main physics goals and the expected accuracies of the anticipated measurements at such a li

M. Cirilli

CP violation in the neutral kaon system is known to be dominated by the mixing of K0 and anti-K0. Direct CP violation in the 2 pion decays of neutral kaons has been a controversial subject over the last decade. A strong experimental effort has been devoted to the precise measurement of the direct CP violation parameter re(epsilon'/epsilon). After 10 year

Rainer Burghardt

We propose a global minimal embedding of the Schwarzschild theory in a five-dimensional flat space by using two surfaces. Covariant field equations are deduced for the gravitational forces.

C. M. Zhang, A. Beesham

For the Dirac particle in the rotational system, the rotation induced inertia effect is analogously treated as the modification of the "spin connection" on the Dirac equation in the flat spacetime, which is determined by the equivalent tetrad. From the point of view of parallelism description of spacetime, the obtained torsion axial-vector is just th

Anthony Kusalik

The Eleventh Workshop on Logic Programming Environments (WLPE'01) was one in a series of international workshops in the topic area. It was held on December 1, 2001 in Paphos, Cyprus as a post-conference workshop at ICLP 2001. Eight refereed papers were presented at the conference. A majority of the papers involved, in some way, constraint logic programmi

A. Correa, K. Hallberg, C. A. Balseiro

We develop a theory for the interactions between magnetic impurities in nanoscopic systems. The case of impurities in quantum corrals built on the (111) Cu surface is analyzed in detail. For elliptical corrals with one impurity, clear magnetic mirages are obtained. This leads to an enhancement of the inter-impurity interactions when two impurities are placed

O. Elgaroy

We calculate the characteristic length scale of a vortex line in a dilute, superfluid gas of fermionic atoms, and find that it is in general smaller, and has a weaker density dependence than the BCS coherence length. Taking this into account, we find the energy of a vortex line to be larger than has previously been estimated. As a consequence, the critical f

G. G. Kozlov

The relaxation of the harmonical oscillator, being in contact with the thermostat whose excitations can be treated as bosons is studied. An exact temporary behavior of the inverse oscillator's temperature is obtained. In low interaction limit the temperature behavior is exponential. When the interaction is increasing the temporary behavior display oscill

J. Steinhauer, R. Ozeri, N. Katz, N. Davidson

We report the first measurement of the excitation spectrum and the static structure factor of a Bose-Einstein condensate. The excitation spectrum displays a linear phonon regime, as well as a parabolic single-particle regime. The linear regime provides an upper limit for the superfluid critical velocity, by the Landau criterion. The excitation spectrum agree

Andrea Cappelli, Marina Huerta, Guillermo R. Zemba

Chiral conformal field theories are characterized by a ground-state current at finite temperature, that could be observed, e.g. in the edge excitations of the quantum Hall effect. We show that the corresponding thermal conductance is directly proportional to the gravitational anomaly of the conformal theory, upon extending the well-known relation between spe

M. V. Milosevic, S. V. Yampolskii, F. M. Peeters

The vortex states in a thin mesoscopic disk are investigated within the phenomenological Ginzburg-Landau theory in the presence of a step-like external magnetic field with zero average which could model the field resulting from a ferromagnetic disk or a current carrying loop. The regions of existence of the multi-vortex state and the giant vortex state are f

Frédéric Piéchon, Gilles Montambaux

Recent experiments on quantum dots in the Coulomb Blockade regime have shown how adding successive electrons into a dot modifies the energy spectrum and the wave functions of the electrons already present in the dot. Using a microscopic model, we study the importance of electron-electron interaction on these ``scrambling'' effects. We compute the Har

O. Gunnarsson, K. Schonhammer

In a recent letter, Zvyagin calculates the density of states for 4f electrons coupled to a conduction band in the framework of the Bethe ansatz (BA) solution for the degenerate Anderson model. It is claimed that the results qualitatively disagree with the results obtained for the same model but using a variational approach. Even the high energy feature in th

D. Alfe`, M. J. Gillan, G. D. Price

A general set of methods is presented for calculating chemical potentials in solid and liquid mixtures using {\em ab initio} techniques based on density functional theory (DFT). The methods are designed to give an {\em ab initio} approach to treating chemical equilibrium between coexisting solid and liquid solutions, and particularly the partitioning ratio o

P. M. Hogan, A. R. Tajbakhsh, E. M. Terentjev

A range of monodomain nematic liquid crystal elastomers containing differing proportions of photo-isomerisable mesogenic moieties, which turn from a rod-like to a kinked shape upon ultraviolet (UV) irradiation, was studied. Depending on the proportion and positional role of the photo-sensitive groups in the crosslinked polymer network, different types and ma

A. M. Dykhne, I. M. Kaganova

We bring forward rather simple algorithm allowing us to calculate the effective impedance of inhomogeneous metals in the frequency region where the local Leontovich (the impedance) boundary conditions are justified. The inhomogeneity is due to the properties of the metal or/and the surface roughness. Our results are nonperturbative ones with respect to the i

Mu-Lin Yan

The Davey-Stewartson 1(DS1) system[9] is an integrable model in two dimensions. A quantum DS1 system with 2 colour-components in two dimensions has been formulated. This two-dimensional problem has been reduced to two one-dimensional many-body problems with 2 colour-components. The solutions of the two-dimensional problem under consideration has been constru

Shun-Qing Shen, X. C. Xie, F. C. Zhang

High-spin systems with orbital degeneracy are studied in the large spin limit. In the absence of Hund's coupling, the classical spin model is mapped onto disconnected orbital systems with spins up and down, respectively. The ground state of the isotropic model is an orbital valence bond state where each bond is an orbital singlet with parallel spins, and

H. Hong, Gun Sang Jeon, M. Y. Choi

We consider a system of coupled oscillators with finite inertia and time-delayed interaction, and investigate the interplay between inertia and delay both analytically and numerically. The phase velocity of the system is examined; revealed in numerical simulations is emergence of spontaneous phase oscillation without external driving, which turns out to be i

Yong-Jun Liu, Chang-De Gong

For a class of quasi-one-dimensional clusters, by using exact diagonalization, we study the effect of side spins on the spin-spin correlations on chain. Our calculations show that the side spins added in the same sublattice can effectively strengthen the spin-spin correlations in large distance region and make the change tend to flat. It is exactly proved th

Girish S. Setlur

The well-studied phenomenon of X-ray edge singularities is revisited using the sea-boson approach that has recently been placed on a rigorous footing. We are able to reproduce the well-known result namely, Mahan's power law divergences. Unlike the work of Schotte and Schotte, no linearization of the bare fermion dispersion is needed, which, by their own

Keiji Saito, Yosuke Kayanuma

Dissipative effects on the nonadiabatic transition for the two and three level systems are studied. When the system is affected by a strong dissipation through the diabatic states, the exact transition probability is enumerated making use of the effective master equation. In the two-level system, we consider the case where the external field is swept from no

D. C. Cabra, M. D. Grynberg, P. C. W. Holdsworth, P. Pujol

We study the magnetic properties of the Kagome antiferromagnet going from the classical limit to the deep quantum regime of spin 1/2 systems. In all the cases there are special values for the magnetization, 1/3 in particular, in which a singular behavior is observed to occur in both the classical and quantum cases. We show clear evidence for a magnetization

M. Picco, F. Ritort, M. Sales

In a previous paper (cond-mat/0106554) we showed the existence of two new zero-temperature exponents (λand θ') in two dimensional Gaussian spin glasses. Here we introduce a novel low-temperature expansion for spin glasses expressed in terms of the gap probability distributions for successive energy levels. After presenting the numerical evidence in favor

Th. M. Nieuwenhuizen, A. E. Allahverdyan

The Brownian motion of a quantum particle in a harmonic confining potential and coupled to a harmonic quantum thermal bath is exactly solvable. It is shown that at low enough temperatures the stationary state is non-Gibbsian due to an entanglement with the bath. In physical terms, this happens when the cloud of bath modes around the particle starts to play a

Philip I. Choi, Puragra Guhathakurta, Kathryn V. Johnston

Surface photometry of the M31 satellites M32 and NGC 205 is compared to numerical simulations of satellite destruction to constrain orbital parameters and the interaction history of the M31 subgroup. Our analysis reveals the following preliminary results: (1) Generic features of tidal disruption in the simulations include an extended ``extra-tidal''

Shwetabh Singh, Chung-Pei Ma

Studies of the growth of cosmic perturbations are typically focused on galactic scales and above. In this paper we investigate the evolution of perturbations in baryons, photons, and dark matter for masses below 10^6 M_\odot (or wavenumbers above 100 Mpc^-1). Fluctuations on these scales are of interest and importance because they grow to become the earliest

E. Athanassoula, A. Misiriotis

We discuss the morphology, photometry and kinematics of the bars which have formed in three N-body simulations. These have initially the same disc and the same halo-to-disc mass ratio, but their haloes have very different central concentrations. The third model includes a bulge. The bar in the model with the centrally concentrated halo (model MH) is much str

Yu. I. Neshpor, N. N. Chalenko, A. A. Stepanian, O. R. Kalekin

The active galactic nucleus BL Lac was observed with the Gt-48 atmospheric Cherenkov detector of the Crimean Astrophysical Observatory from July 23-September 1, 1998, in order to search for ultrahigh-energy gamma-ray (>1 TeV) emission. The object was in the field of view of the detector for more than 24 hours. The source was detected with a high level of con

A. C. Katsiyannis, M. Mathioudakis, K. J. H. Phillips, D. R. Williams

The Solar Eclipse Coronal Imaging System (SECIS) is a simple and extremely fast, high-resolution imaging instrument designed for studies of the solar corona. Light from the corona (during, for example, a total solar eclipse) is reflected off a heliostat and passes via a Schmidt-Cassegrain telescope and beam splitter to two CCD cameras capable of imaging at 6

Boris Dintrans, Michel Rieutord

After showing that the anelastic approximation is better than the subseismic one to filter out acoustic waves when studying low-frequency stellar oscillations, we compute gravito-inertial modes of a typical Gamma-Doradus star using this approximation. We show that eigenmodes can be regular or singular, according to the possible focusing towards attractors of

V. A. Dogiel, V. Schoenfelder, A. W. Strong

We investigate the origin of the nonthermal X-ray emission from the Galactic ridge in the range 10-200 keV. We consider bremsstrahlung of subrelativistic cosmic ray protons and electrons as production processes. From the solution of the kinetic equations describing the processes of particle in-situ acceleration and spatial propagation we derive parameters of

Manfred P. Leubner

Most astrophysical plasmas are observed to have velocity distribution functions exhibiting non-Maxwellian suprathermal tails. The high energy particle populations are accurately represented by the family of kappa-distributions where the use of these distributions has been unjustly criticized because of a perceived lack of theoretical justification. We show t

A. C. Katsiyannis, P. Boumis, J. Meaburn

The UK Schmidt camera was used to observe the Virgo cluster of galaxies, where a total of 13 R-band Kodak Tech-Pan films were obtained. The latter, were scanned by the APM machine (Cambridge, UK),digitally aligned, co-added, corrected for vignetting effects andfinally cleaned of stellar features. The resulting image covers an area of ~6.2x6.2 degree^2 with a

Vladimir V. Usov

Strange quark matter with the density of ~ 5\times 10^{14} g cm^{-3} might exist up to the surface of a strange star. This differs qualitatively from the case of a neutron star and opens observational possibilities to distinguish strange stars from neutron stars. The thermal emission of photons and e^+e^- pairs from the bare (or nearly bare) quark surface of

Frank Verbunt

X-ray bursts from bright sources in globular clusters of our galaxy show that at least 11 (of a total 13) of these sources are neutron stars. One of the low-luminosity X-ray sources in omega Cen is a neutron star accreting at a low rate. Together with the discoveries that M~15 contains two bright X-ray sources, and that 47 Tuc and NGC 6440 contain 2 and 5 lo

G. F. Burgio, M. Baldo, P. K. Sahu, A. B. Santra

Massive neutron stars (NS) are expected to possess a quark core. While the hadronic side of the NS equation of state (EOS) can be considered well established, the quark side is quite uncertain. While calculating the EOS of hadronic matter we have used the Brueckner-Bethe-Goldstone formalism with realistic two-body and three-body forces, as well as a relativi

Frank Verbunt

The twelve bright (Lx>10(36) erg/s) X-ray sources in the globular clusters have lower luminosities than the brightest sources in the bulge of our galaxy. The dim (Lx<10(35) erg/s) X-ray sources in globular clusters reach higher luminosities than the cataclysmic variables in the disk of our galaxy. The first difference is a statistical fluke, as comparison wi

V. E. Kuzmichev, V. V. Kuzmichev

Old and new puzzles of cosmology are reexamined from the point of view of quantum theory of the universe developed here. It is shown that in proposed approach the difficulties of the standard cosmology do not arise. The theory predicts the observed dimensions of nonhomogeneities of matter density and the amplitude of fluctuations of the cosmic background rad

W. Reich, E. Fuerst, P. Reich, R. Wielebinski

We report on sensitive 21cm and 11cm polarization surveys of the Galactic plane carried out with the Effelsberg 100-m telescope at arcmin angular resolution and some related work. Highly structured polarized emission is seen along the Galactic plane as well as up to very high Galactic latitudes. These observations reflect Faraday effects in the interstellar

Nozomu Kawakatu, Masayuki Umemura

We quantitatively scrutinize the effects of the radiation drag arising from the radiation fields in a galactic bulge in order to examine the possibility that the radiation drag could be an effective mechanism to extract angular momentum in a spheroidal system like a bulge and allow plenty of gas to accrete onto the galactic center. For this purpose, we numer

G. Mark Voit, Greg L. Bryan

Clusters of galaxies are thought to contain about ten times as much dark matter as baryonic matter. The dark component therefore dominates the gravitational potential of the cluster, and the baryons confined by this potential radiate X-rays with a luminosity that depends mainly on the gas density in the cluster&#39;s core. Predictions of the X-rays&#39; prop

Hong Wu, Dave Burstein, Zugan Deng

We present a deep, 42.79 hr image of the nearby, edge-on galaxy NGC 4565 in the Beijing-Arizona-Taipei-Connecticut (BATC) 6660A band using the large-format CCD system on the 0.6m Schmidt telescope at the Xinglong Station of the National Astronomical Observatories of China (NAOC). we obtain a final image that is calibrated to an accuracy of 0.02 mag in zero p

Ryoko Ishioka, Makoto Uemura, Katsura Matsumoto, Hiroyuki Ohashi

We report on time-series photometric observations in the earliest stages of superoutbursts of the extreme dwarf novae, AL Com and WZ Sge, which started on 2001 May after the 6 years quiescence and on 2001 July after the 23 years quiescence, respectively. We detected growth of ``early superhumps&#39;&#39; during the each rising stage. Our observations reject

Douglas C. -J. Bock, V. V. Gvaramadze

We present some arguments in support of the association of the pulsar PSR B1706-44 with the supernova remnant G343.1-2.3, based on the idea that these objects could be the result of a supernova explosion within a mushroom-like cavity (created by the supernova progenitor wind breaking out of the parent molecular cloud). We suggest that in addition to the know

Hisakazu Minakata, Hiroaki Sugiyama

We point out under the assumption of Majorana neutrinos that a lower bound on the MNS matrix element |U_{e3}|^2 can be derived by using constraint imposed by neutrinoless double beta decay experiments and by positive detection of neutrino mass by single beta decay experiments. We show that the lower bound exists in a narrow region of the ratio of the observa

T. R. Kirkpatrick, D. Belitz

Dephasing of electrons due to the electron-electron interaction has recently been the subject of a controversial debate, with different calculations yielding mutually incompatible results. In this paper we prove, by means of Ward identities, that neither a Coulomb interaction nor a short-ranged model interaction can lead to phase breaking at zero temperature

E. Leader, A. V. Sidorov, D. B. Stamenov

We present a new leading and next-to-leading QCD analysis of the world data on inclusive polarized deep inelastic scattering. A new set of polarized parton densities is extracted from the data and the sensitivity of the results to the newly incorporated SLAC/E155 proton data is discussed.

M. Choudhury, A. R. Rao, S. V. Vadawale, C. H. Ishwara-Chandra

We present the results of a detailed correlation study between the soft X-ray, hard X-ray, and radio emission (obtained from RXTE ASM, BATSE, and GBI observations, respectively) of the bright radio emitting Galactic X-ray binary Cygnus X-3. We detect a very strong positive correlation between the soft X-ray and radio emission during the low-hard and minor fl