July 2001 arXiv papers — page 11

Anjan S. Joshipura, Rishikesh D. Vaidya, Sudhir K. Vempati

The structure of neutrino masses and mixing resulting from trilinear $R$ violating interactions is studied in the presence of the gauge mediated supersymmetry breaking. Neutrino masses arise in this model at tree level through the RG-induced vacuum expectation values of the sneutrinos and also through direct contribution at 1-loop. The relative importance of

P. D. Jarvis, J. D. Bashford

A calculational framework is proposed for phylogenetics, using nonlocal quantum field theories in hypercubic geometry. Quadratic terms in the Hamiltonian give the underlying Markov dynamics, while higher degree terms represent branching events. The spatial dimension L is the number of leaves of the evolutionary tree under consideration. Momentum conservation

Emily Chattopadhyay, Indrani Bose

In this paper, we construct a class of spin-1/2 antiferromagnetic (AFM) two-chain ladder models consisting of blocks of n-spin tetrahedral clusters alternating with two-spin rungs. For n=4 and 6 and in extended parameter regimes, the exact ground state of the ladder is shown to be a product of the ground states of the rungs and the n-spin blocks, in both zer

Anatoly Konechny, O. Teoman Turgut

We study a large N_{c} limit of a two-dimensional Yang-Mills theory coupled to bosons and fermions in the fundamental representation. Extending an approach due to Rajeev we show that the limiting theory can be described as a classical Hamiltonian system whose phase space is an infinite-dimensional supergrassmannian. The linear approximation to the equations

D. K. Park, Hungsoo Kim, Yan-Gang Miao, H. J. W. Müller-Kirsten

The effect of temperature is investigated in the Randall-Sundrum brane-world scenario. It is shown that for a spacetime ansatz motivated by similarity with AdS/CFT correspondence several features of the model, such as its $Z_2$ symmetry, are not maintained at nonzero temperatures.

Somshubhro Bandyopadhyay, Vwani Roychowdhury

We show that entanglement-assisted transformations of bipartite entangled states can be more efficient than catalysis [D. Jonathan and M. B. Plenio, Phys. Rev. Lett. 83, 3566 (1999)}, i.e., given two incomparable bipartite states not only can the transformation be enabled by performing collective operations with an auxiliary entangled state, but the entangle

Timothy H. Boyer

Classical electromagnetic forces can account for the experimentally observed phase shifts seen in an electron interference pattern when a line of electric dipoles or a line of magnetic dipoles (a solenoid) is placed between the electron beams forming the interference pattern.

R. de la Madrid

In formal scattering theory, Green functions are obtained as solutions of a distributional equation. In this paper, we use the Sturm-Liouville theory to compute Green functions within a rigorous mathematical theory. We shall show that both the Sturm-Liouville theory and the formal treatment yield the same Green functions. We shall also show how the analytici

B. Bagchi, S. Mullik, C. Quesne, R. Roychoudhury

We consider a PT Symmetric Partner to Khare Mandal's recently proposed non-Hermitian potential with complex eigen values. Our potential is Quasi-Exactly solvable and is shown to possess only real eigen values.

R. M. Jones, N. M. Kroll, T. Higo, Z. Li

Recent experiments at SLAC [1,2] and CERN [3] have revealed evidence of significant deformation in the form of "pitting" of the cells of the 1.8m series of structures DDS/RDDS (Damped Detuned Structure/Rounded Damped Detuned Structure). This pitting occurs in the high group velocity (vg /c = 0.012) end of the accelerating structure and little evidenc

R. M. Jones, N. M. Kroll, T. Higo, R. H. Miller

Operating the SLAC/KEK DDS (Damped Detuned Structure) X-band linacs at high gradients (in excess of 70MV/m) has recently been found to be limited by the accelerator structures breaking down and as a consequence severe damage occurs to the cells which makes the structures inoperable. A series of recent experiments at SLAC indicates that arcing in the structur

James D. Brownridge, Sol Raboy

Measurements of the polarization charge accumulated at the -z and the +z bases of the pyroelectric crystals of LiNbO3 and LiTaO3 during changes in temperature are described. An electrometer in the charge mode with its probe attached to the base under study was used. A reference for the electrometer was established by grounding the electrometer probe at a spe

Takaharu Otsuka, Rintaro Fujimoto, Yutaka Utsuno, B. Alex Brown

The magic numbers in exotic nuclei are discussed, and their novel origin is shown to be the spin-isospin dependent part of the nucleon-nucleon interaction in nuclei. The importance and robustness of this mechanism is shown in terms of meson exchange, G-matrix and QCD theories. In neutron-rich exotic nuclei, magic numbers such as N = 8, 20, etc. can disappear

H. Nakada, M. Sato

We develop a new method of implementing the Hartree-Fock calculations. A class of Gaussian bases is assumed, which includes the Kamimura-Gauss basis-set as well as the set equivalent to the harmonic-oscillator basis-set. By using the Fourier transformation to calculate the interaction matrix elements, we can treat various interactions in a unified manner, in

I. Chemakin, V. Cianciolo, B. A. Cole, R. Fernow

Inclusive and semi-inclusive measurements are presented for antiproton ($\bar{p}$) production in proton-nucleus collisions at the AGS. The inclusive yields per event increase strongly with increasing beam energy and decrease slightly with increasing target mass. The $\bar{p}$ yield in 17.5 GeV/c p+Au collisions decreases with grey track multiplicity, $N_g$,

L. A. Kalyakin

Autoresonance is a phase locking phenomenon occurring in nonlinear oscislatory system, which is forced by oscillating perturbation. Many physical applicatcons of the autoresonance are known in nonlenear physics. The essence of the phenomecon is that the nonlinear oscillator selfadjusts to the varying external conditions so that it remains in resonance with t

Ivan Avramidi

We give a short overview of the effective action approach in quantum field theory and quantum gravity and describe various methods for calculation of the asymptotic expansion of the heat kernel for second-order elliptic partial differential operators acting on sections of vector bundles over a compact Riemannian manifold. We consider both Laplace type operat

Lawrence Goldman

For a large class of systems of o.d.e.'s which have first integrals, the method of arrays yields the following results: i) The first integrals $I$ can be found by solving systems of linear equations. ii) How the first integral $I$ responds to changes in the system $S$. iii) An easy way for finding the first integral for a special class of first integrals

David W. Dreisigmeyer, Peter M. Young

We show that, for a class of systems described by a Lagrangian L(x,\dot{x},t) = 1/2\dot{x}^{2} - V(x,t) the propagator can be reduced via Noether's Theorem to a standard path integral multiplied by a phase factor. Using Henstock's integration technique, this path integral is given a firm mathematical basis. Finally, we recast the propagator as an evo

Tony Shaska, Helmut Voelklein

We study genus 2 function fields with elliptic subfields of degree 2. The locus $Ł_2$ of these fields is a 2-dimensional subvariety of the moduli space $\mathcal M_2$ of genus 2 fields. An equation for $Ł_2$ is already in the work of Clebsch and Bolza. We use a birational parameterization of $Ł_2$ by affine 2-space to study the relation between the j-invaria

Bertrand Patureau-Mirand

Pulling back the weight system associated with the spinor representation of the Lie algebra so(7) by the universal Vassiliev-Kontsevich invariant yields a numerical link invariant with values in formal power series. Computing some skein relations satisfied by this invariant, I derive a recursive algorithm for its evaluation. The values of this invariant belo

Dmitriy Bilik, Vladimir Kadets, Roman Shvidkoy, Dirk Werner

We show that if $T$ is a narrow operator on $X=X_{1}\oplus_{1} X_{2}$ or $X=X_{1}\oplus_{\infty} X_{2}$, then the restrictions to $X_{1}$ and $X_{2}$ are narrow and conversely. We also characterise by a version of the Daugavet property for positive operators on Banach lattices which unconditional sums of Banach spaces inherit the Daugavet property, and we st

Christian Haase, Günter M. Ziegler

The combinatorial structure of a d-dimensional simple convex polytope can be reconstructed from its abstract graph [Blind & Mani 1987, Kalai 1988]. However, no polynomial/efficient algorithm is known for this task, although a polynomially checkable certificate for the correct reconstruction was found by [Joswig, Kaibel & Koerner 2000]. A much stronger certif

V. Manuilov, K. Thomsen

Let $A$ be a separable $C^*$-algebra and $B$ a stable $C^*$-algebra containing a strictly positive element. We show that the group $\Ext(SA,B)$ of unitary equivalence classes of extensions of $SA$ by $B$, modulo the extensions which are asymptotically split, coincides with the group of homotopy classes of such extensions. This is done by proving that the Con

Ian I. Kogan, Nuno B. B. Reis

We add a simple boundary term to the Polyakov action and construct a new class of D-branes with a single null direction. On the string world-sheet the system is described by a single quantized left-mode sector of a conformal field theory. By a Wick rotation of spacetime, we map open strings attached to these branes into chiral closed strings. We suggest that

C. I. Lazaroiu

I discuss tree-level amplitudes in cubic topological string field theory, showing that a certain family of gauge conditions leads to an A-infty algebra of tree-level string products which define a potential describing the dynamics of physical states. Upon using results of modern deformation theory, I show that the string moduli space admits two equivalent de

Paolo Budinich

The Cartan's equations definig simple spinors (renamed pure by C. Chevalley) are interpreted as equations of motion in momentum spaces, in a constructive approach in which at each step the dimesions of spinor space are doubled while those momentum space increased by two. The construction is possible only in the frame of geometry of simple or pure spinors

N. V. Mikheev, M. V. Chistyakov

Damping of an electromagnetic wave in a strong magnetic field is analyzed in the kinematic region near the threshold of electron-positron pair production. Damping of the electromagnetic field is shown to be noticeably nonexponential in this region. The resulting width of the photon $γ\to e^+ e^-$ decay is considerably smaller than previously known results.

J. Kenichi Mizukoshi, Howard Baer, A. S. Belyaev, Xerxes Tata

It is generally accepted that experiments at an e+e- linear colliders will be able to extract the masses of the selectron as well as the associated sneutrinos with a precision of ~ 1% by determining the kinematic end points of the energy spectrum of daughter electrons produced in their two body decays to a lighter neutralino or chargino. Recently, it has bee

Rula Tabbash

We argue that identifying the electroweak Higgs particle with the extra components of the gauge field in $4+d$ dimensions provides a solution to the hierarchy problem. The absence of ultraviolate quadratic divergences is due to the fact that the Higgs mass is protected by an exact gauge symmetry at energies beyond the cutoff. The idea is implemented within e

Hans Peter Nilles, Keith A. Olive, Marco Peloso

We consider the potential problems due to the production of inflatinos and gravitinos after inflation. Inflationary models with a single scale set by the microwave background anisotropies have a low enough reheat temperature to avoid problems with the thermal production of gravitinos. Moreover, the nonthermal production of gravitinos has been shown to be suf

Cristina Manuel, Krishna Rajagopal

We imagine shining light on a lump of cold dense quark matter, in the CFL phase and therefore a transparent insulator. We calculate the angles of reflection and refraction, and the intensity of the reflected and refracted light. Although the only potentially observable context for this phenomenon (reflection of light from and refraction of light through an i

L. Micu

We establish a relation between the solution of a relativistic bound state equation in quantum mechanics and the field representation of a bound state with the aid of creation and annihilation operators. We show that a bound system can be represented by a gas of free constituents and a classical effective field representing the countless quantum fluctuations

Y. Kiyo

Future e^+ e^- linear colliders will enable us to determine the top quark mass with high accuracy from the measurement of the 1S peak position of (remnant of) toponium. The estimated statistical error in this measurement is about 50 MeV with integrated luminosity of 30 ${\rm fb^{-1}}$. We calculate ${\cal O}(α_s^5 m)$ corrections to the quarkonium 1S energy

J. -M. Laget

At high energy, the photoproduction or electroproduction of Vector Mesons allow to prepare a beam of quark-antiquark pairs of a given flavor. At high momentum transfer, the study of the scattering of these pairs on a nucleon opens up an original window on the quark-gluon structure of hadronic matter, which may eventually shed light on its gluonic content, on

Vicente Pleitez

Taking into account that neutrinos are massive particles and that they are produced mainly as states of negative helicity, we show that the neutral and charged current interactions change these neutrinos into transversally polarized states. This implies a considerable reduction of the neutrino flux when propagating through ordinary matter (electrons, protons

The OPAL collaboration, G. Abbiendi

The process e+ e- -> e+ e- Z/gamma* is studied with the OPAL detector at LEP at a centre of mass energy of sqrt(s) = 189 GeV. The cross-section times the branching ratio of the Z/gamma* decaying into hadrons is measured within Lorentz invariant kinematic limits to be (1.2 +/- 0.3 +/- 0.1) pb for invariant masses of the hadronic system between 5 GeV and 60 Ge

The OPAL collaboration, G. Abbiendi

Data on muon pair production obtained by the OPAL collaboration at centre of mass energies near the Z peak are analysed. Small angular mismatches between the directions of the two muons are used to assess the effects of initial state photon radiation and initial-final-state radiation interference on the forward-backward asymmetry of muon pairs. The dependenc

Duncan Noltingk

We consider the extension of classical history theory to the massive vector field and electromagnetism. It is argued that the action of the two Poincare groups introduced by Savvidou suggests that the history fields should have five components. The extra degrees of freedom introduced to make the fields five-dimensional result in an extra pair of second class

Deborah East. Miroslaw Truszczynski

We present an implementation of an answer-set programming paradigm, called aspps (short for answer-set programming with propositional schemata). The system aspps is designed to process PS+ theories. It consists of two basic modules. The first module, psgrnd, grounds an PS+ theory. The second module, referred to as aspps, is a solver. It computes models of gr

Deborah East, Miroslaw Truszczynski

We show that propositional logic and its extensions can support answer-set programming in the same way stable logic programming and disjunctive logic programming do. To this end, we introduce a logic based on the logic of propositional schemata and on a version of the Closed World Assumption. We call it the extended logic of propositional schemata with CWA (

Victor Marek, Inna Pivkina, Miroslaw Truszczynski

Revision programming is a formalism to describe and enforce updates of belief sets and databases. That formalism was extended by Fitting who assigned annotations to revision atoms. Annotations provide a way to quantify the confidence (probability) that a revision atom holds. The main goal of our paper is to reexamine the work of Fitting, argue that his seman

G. A. Luna-Acosta, J. A. Méndez-Bermúdez, P. Šeba, K. N. Pichugin

The purely classical counterpart of the Scattering Probability Matrix (SPM) $\mid S_{n,m}\mid^2$ of the quantum scattering matrix $S$ is defined for 2D quantum waveguides for an arbitrary number of propagating modes $M$. We compare the quantum and classical structures of $\mid S_{n,m}\mid^2$ for a waveguide with generic Hamiltonian chaos. It is shown that ev

Soon-Hyung Yook, Hawoong Jeong, Albert-Laszlo Barabasi

Network generators that capture the Internet's large-scale topology are crucial for the development of efficient routing protocols and modeling Internet traffic. Our ability to design realistic generators is limited by the incomplete understanding of the fundamental driving forces that affect the Internet's evolution. By combining the most extensive

Paul Tangney, Sandro Scandolo

We derive an analytic expression for the average difference between the forces on the ions in a Car-Parrinello simulation and the forces obtained at the same ionic positions when the electrons are at their ground state. We show that for common values of the fictitious electron mass, a systematic bias may affect the Car-Parrinello forces in systems where the

T. Fennell, O. A. Petrenko, G. Balakrishnan, S. T. Bramwell

Neutron scattering has been used to investigate the magnetic correlations in the the spin ice material dysprosium titanate, Dy2Ti2O7. An isotopically enriched sample was used to minimise neutron absorption. In zero field no magnetic order was observed down to 50 mK but the magnetic diffuse scattering was in qualitative agreement with that expected for the di

F. Hohls, U. Zeitler, R. J. Haug

We have measured the temperature dependence of the conductivity $σ_{xx}$ of a two-dimensional electron system deep into the localized regime of the quantum Hall plateau transition. Using variable-range hopping theory we are able to extract directly the localization length $ξ$ from this experiment. We use our results to study the scaling behavior of $ξ$ as a

Semjon Stepanow

We consider the adsorption of a semiflexible polymer chain onto interfaces and surfaces by using the differential equation of the distribution function $G(R,L)$ of the end-to-end distance $R$, which is associated with the moment expansion of the latter. We present the results of the approximative treatment consisting of taking into account the 2nd and 4th mo

Y. Noat, R. Deblock, B. Reulet, H. Bouchiat

In order to understand how screening is modified by electronic interferences in a mesoscopic isolated system, we have computed both analytically and numerically the average thermodynamic and time dependent polarisabilities of two dimensional mesoscopic samples in the presence of an Aharonov-Bohm flux. Two geometries have been considered: rings and squares. M

Alexandre Rosas, Sérgio Coutinho

The ground state critical properties of the Random Field Ising Model (RFIM) on the diamond hierarchical lattice are investigated via a combining method encompassing real space renormalization group and an exact recurrence procedure. The local magnetization and the nearest neighbors pair correlation function are exactly calculated. The fixed-point joint proba

J. A. Skinta, T. R. Lemberger, E. Wertz, K. Wu

From study of the Kosterlitz-Thouless-Berezinskii (KTB) transition in the superfluid density, n_s(T), of ultrathin c-axis oriented YBa_{2}Cu_{3}O_{7-δ} (YBCO) films, we find that interlayer coupling is unexpectedly strong. The KTB transition occurs at a high temperature, as if the films were isotropic rather than quasi-two-dimensional. This result agrees wit

Peixun Luo, K. Y. Michael Wong

We analyze the learning of noisy teacher-generated examples by nonlinear and differentiable student perceptrons using the cavity method. The generic activation of an example is a function of the cavity activation of the example, which is its activation in the perceptron that learns without the example. Mean field equations for the macroscopic parameters and

Alexandre Rosas, Sérgio Coutinho

The phase diagram and the thermodynamics of the random field Ising model (RFIM) defined on a family of diamond hierarchical lattices of arbitrary dimension and scaling factor $b=2$ is investigated. The phase diagram is studied considering the flow of the renormalized joint probability distributions of couplings and fields. A continuous (Gaussian) and a discr

Dominic J. Lee, Ian D. Lawrie

If the zero-field transition in high temperature superconductors such as YBa_2Cu_3O_7-δis a critical point in the universality class of the 3-dimensional XY model, then the general theory of critical phenomena predicts the existence of a critical region in which thermodynamic functions have a characteristic scaling form. We report the first attempt to calcul

Saburo Takahashi, Taro Yamashita, Hiroshi Imamura, Sadamichi Maekawa

The effect of spin relaxation on tunnel magnetoresistance (TMR) in a ferromagnet/superconductor/ferromagnet (FM/SC/FM) double tunnel junction is theoretically studied. The spin accumulation in SC is determined by balancing of the spin-injection rate and the spin-relaxation rate. In the superconducting state, the spin-relaxation time becomes longer with decre

Ian D. Lawrie, Dominic J. Lee

A renormalization-group scheme is developed for the 3-dimensional O($2N$)-symmetric Ginzburg-Landau-Wilson model, which is consistent with the use of a 1/N expansion as a systematic method of approximation. It is motivated by an application to the critical properties of superconductors, reported in a separate paper. Within this scheme, the infrared stable fi

D. Naumovic, P. Aebi, L. Schlapbach, C. Beeli

We report the in situ formation of an ordered equilibrium decagonal Al-Pd-Mn quasicrystal overlayer on the 5-fold symmetric surface of an icosahedral Al-Pd-Mn monograin. The decagonal structure of the epilayer is evidenced by x-ray photoelectron diffraction, low-energy electron diffraction and electron backscatter diffraction. This overlayer is also characte

Indrani Bose

Quantum magnetism is one of the most active areas of research in condensed matter physics. There is significant research interest specially in low-dimensional quantum spin systems. Such systems have a large number of experimental realizations and exhibit a variety of phenomena the origin of which can be attributed to quantum effects and low dimensions. In th

David Sanchez, A. H. MacDonald, Gloria Platero

We develop a theory of non-linear growth direction transport in magnetically doped II-VI compound semiconductor multiple-quantum-well systems. We find that the formation of electric field domains can be controlled by manipulating the space dependence of the band electron spin-polarization, using its exchange coupling to local moments. We emphasize the import

Niurka R. Quintero, Angel Sanchez, Franz G. Mertens

We study the dynamics of kinks in the $ϕ^4$ model subjected to a parametric ac force, both with and without damping, as a paradigm of solitary waves with internal modes. By using a collective coordinate approach, we find that the parametric force has a non-parametric effect on the kink motion. Specifically, we find that the internal mode leads to a resonance

N. V. Agudov, B. Spagnolo

We study the effect of noise-enhanced stability of periodically driven metastable states in a system described by piecewise linear potential. We find that the growing of the average escape time with the intensity of the noise is depending on the initial condition of the system. We analytically obtain the condition for the noise enhanced stability effect and

A. Garcia-Martin, J. J. Saenz

The full distribution of the conductance $P(G)$ in quasi-one-dimensional wires with rough surfaces is analyzed from the diffusive to the localization regime. In the crossover region, where the statistics is dominated by only one or two eigenchannels, the numerically obtained P(G) is found to be independent of the details of the system with the average conduc

M. A. Cirone, F. de Pasquale, B. Spagnolo

We analyze the nonlinear relaxation of a complex ecosystem composed of many interacting species. The ecological system is described by generalized Lotka-Volterra equations with a multiplicative noise. The transient dynamics is studied in the framework of the mean field theory and with random interaction between the species. We focus on the statistical proper

I. Albert, J. G. Sample, A. J. Morss, S. Rajagopalan

We study the drag force on discrete objects with circular cross section moving slowly through a spherical granular medium. Variations in the geometry of the dragged object change the drag force only by a small fraction relative to shape effects in fluid drag. The drag force depends quadratically on the object's diameter as expected. We do observe, howeve

I. Zivkovic, Y. Hirai, M. Prester, D. Drobac

We report ac susceptibility measurements on polycrystalline samples of SrRuO_3 and three ruthenocuprates: superconducting RuSr_2GdCu_2O_8 (Ru-1212), superconducting RuSr_2Eu_(2-x)Ce_xCu_2O_y (Ru-1222, x=0.5) and nonsuperconducting, insulating RuSr_2Eu_(2-x)Ce_xCu_2O_z (Ru-1222, x=1.0). Ac susceptibility of both Ru-1222 compositions exhibit logarithmic time r

Christoph Jurecka, Wolfram Brenig

We present an analytic theory for the energy spectrum of a two-leg spin ladder doped with two holes. Starting from a pseudo-fermion-bond-boson representation of the corresponding $t_{1,2}-J_{1,2}$ Hamiltonian we apply a diagrammatic approach adapted to the limit of strong rung coupling, which includes both, the coupling of holes to the spin background as wel

W. N. Brandt, A. E. Hornschemeier, D. P. Schneider, D. M. Alexander

We present results from stacking analyses, using the 1 Ms Chandra Deep Field North data, that constrain the X-ray emission of Lyman break galaxies at z = 2-4. Stacking the counts from 24 individually undetected Lyman break galaxies located within the Hubble Deep Field North, we have obtained average detections of these objects in the resulting 0.5-8.0 keV an

A. Saha, Allan Sandage, G. A. Tammann, A. E. Dolphin

Repeated imaging observations have been made of NGC 3982 with the Hubble Space Telescope between March and May 2000, over an interval of 53 days. Images were obtained on 12 epochs in the F555W band and on five epochs in the F814W band. The galaxy hosted the type Ia supernova SN1998aq. A total of 26 Cepheid candidates were identified, with periods ranging fro

C. Horellou, J. H. Black, J. H. van Gorkom, F. Combes

We present and interpret observations of atomic and molecular gas toward the southern elliptical galaxy NGC 1316 (Fornax A), a strong double-lobe radio source with a disturbed optical morphology that includes numerous shells and loops. The 12CO(1-0), 12CO(2-1), and HI observations were made with SEST and the VLA. CO emission corresponding to a total molecula

Brian D. Fields, Keith A. Olive, Joseph Silk, Michel Casse

Recent observations suggest the existence of a white dwarf population in the Galactic halo, while others suggest that deuterium has been astrated in systems at high redshift and low metallicity. We propose that these observations could be signatures of an early population of intermediate-mass stars. Such a population requires a Population III initial mass fu

B. Mobasher, T. J. Bridges, D. Carter, B. Poggianti

This is the second paper in a series studying the photometric and spectroscopic properties of galaxies of different luminosities in the Coma cluster. The sample selection, spectroscopic observations and completeness functions are presented here. To study the spectral properties of galaxies as a function of their local environment, two fields were selected fo

J. L. Sanz, D. Herranz, E. Martinez-Gonzalez

This paper introduces the use of pseudo-filters that optimize the detection/extraction of sources on a background. We assume as a first approach that such sources are described by a spherical (central) profile and that the background is represented by a homogeneous and isotropic random field. We make an n-dimensional treatment making emphasis in astrophysica

I. Szapudi, S. Prunet, S. Colombi

Szapudi et al (2001) introduced the method of estimating angular power spectrum of the CMB sky via heuristically weighted correlation functions. Part of the new technique is that all (co)variances are evaluated by massive Monte Carlo simulations, therefore a fast way to measure correlation functions in a high resolution map is essential. This letter presents

A. Bonanno, A. L. Murabito, L. Paterno'

We study the sensitivity of the sound speed to relativistic corrections of the equation of state (EOS) in the standard solar model by means of a helioseismic forward analysis. We use the latest GOLF/SOHO data for $\ell = 0,1,2,3$ modes to confirm that the inclusion of the relativistic corrections to the adiabatic exponent $Γ_1$ computed from both OPAL and MH

M. Schultheis, I. S. Glass

In this work, a sample of luminous M-type giants in the Baade's Windows towards the inner Galactic Bulge is investigated in the near-infrared. The ISOGAL survey at 7 and 15 micron has given information concerning the mass-loss rates of these stars and their variability characteristics have been extracted from the MACHO database. Most are known to be semi

Jens Woitas, Christoph Leinert, Rainer K"ohler

Using near-infrared speckle interferometry we have obtained resolved JHK-photometry for the components of 58 young binary systems. From these measurements, combined with other data taken from literature, we derive masses and particularly mass ratios of the components. We use the J-magnitude as an indicator for the stellar luminosity and assign the optical sp

A. Schroeder, M. J. Drinkwater, O. -G. Richter

We present a new set of deep HI observations of member galaxies of the Fornax cluster. We detected 35 cluster galaxies in HI. The resulting sample, the most comprehensive to date, is used to investigate the distribution of HI in the cluster galaxies. We compare the HI content of the detected cluster galaxies with that of field galaxies by measuring HI mass-t

A. Orr, P. Barr, M. Guainazzi, A. N. Parmar

We present the 0.1-200 keV BeppoSAX spectrum of MR 2251-178 observed at two epochs in 1998 separated by 5 months. Both epochs show identical spectral shape and X-ray flux. Analysis of the combined spectra allow us to confirm the presence of the ionized Fe K-alpha line detected by ASCA and to test the presence of reflection from ionized material. The best sel

P. A. Caraveo

The vast majority of the high-energy gamma-ray sources discovered by EGRET are still unidentified. Percentages range from 50% at high galactic latitudes, where blazars are responsible for almost all identified sources, to more than 90% near the galactic plane, where isolated neutron stars appear to be the only certified class of sources of high energy gamma-

I. Iwata, K. Ohta, K. Nakanishi, K. Kohno

We present a result of the quasar CO(J=6-5) observations of SDSSp J104433.04-012502.2 at z = 5.8. Ten-days observations with the Nobeyama Millimeter Array yielded an rms noise level of ~ 2.1 mJy/beam in a frequency range from 101.28 GHz to 101.99 GHz at a velocity resolution of 120 km/s. No significant clear emission line was detected in the observed field a

M. Terasawa, K. Sumiyoshi, T. Kajino, G. J. Mathews

We study the role of light neutron-rich nuclei during r-process nucleosynthesis in supernovae. Most previous studies of the r-process have concentrated on the reaction flow of heavy unstable nuclei. Although the nuclear reaction network includes a few thousand heavy nuclei, only limited reaction flow through light-mass nuclei near the stability line has been

Erwin de Blok, Stacy McGaugh, Vera Rubin

We present mass models for a sample of 30 high-resolution rotation curves of low surface brightness (LSB) galaxies. We fit both pseudo-isothermal (core-dominated) and Cold Dark Matter (CDM) (cusp-dominated) halos for a wide variety of assumptions about the stellar mass-to-light ratio. We find that the pseudo-isothermal model provides superior fits. CDM fits

T. Nikola, N. Geis, F. Herrmann, S. C. Madden

We have mapped the inner 360'' regions of M51 in the 158micron [CII] line at 55'' spatial resolution using the Far-infrared Imaging Fabry-Perot Interferometer (FIFI) on the Kuiper Airborne Observatory (KAO). The emission is peaked at the nucleus, but is detectable over the entire region mapped, which covers much of the optical disk of the gal

C. Da Rocha, C. Mendes de Oliveira, M. Bolte, B. L. Ziegler

We have obtained deep photometry of NGC 1199 (in HCG 22) and NGC 6868 (in the Telescopium group). Both galaxies are the optically brightest galaxies of their groups. Our analysis of B and R images taken with the Keck II and the VLT/ESO telescopes, detected a population of globular clusters around both galaxies, with total specific frequencies S_N=1.7\pm0.6 f

Ravi Subrahmanyan

I discuss the capabilities and limitations of the AMiBA for imaging CMB anisotropies. Michael Kesteven (ATNF-CSIRO) has proposed drift-scanning as an observing strategy for measuring and rejecting any instrumental response that the close-packed interferometers may have to the local environment. The advantages of mosaic imaging CMB anisotropies using a co-mou

Lorella Angelini, Michael Loewenstein, Richard F. Mushotzky

We report on the {\it Chandra} observations of the elliptical galaxy NGC 1399, concentrating on the X-ray sources identified with globular clusters (GCs). A large fraction of the 2-10 keV X-ray emission in the $8' \times 8'$ {\it Chandra} image is resolved into point sources with luminosities $\ge 5 \times 10^{37}$ \ergsec. These sources are most lik

Henry G. Roe, James R. Graham, Ian S. McLean, Imke de Pater

We present 2.03-2.30 micron near-infrared spectroscopy of Neptune taken 1999 June 2 (UT) with the W.M. Keck Observatory's near-infrared spectrometer (NIRSPEC) during the commissioning of the instrument. The spectrum is dominated by a bright cloud feature, possibly a storm or upwelling, in the southern hemisphere at approximately 50 degrees S latitude. Th

David Merritt, Laura Ferrarese, Charles L. Joseph

We analyze optical long-slit spectroscopy of the nucleus of M33 obtained from the Space Telescope Imaging Spectrograph aboard the Hubble Space Telescope. Rather than the steep rise expected within the radius of influence of a supermassive black hole, the velocity dispersion drops significantly within the inner parsec. Dynamical modelling yields an estimated

Michael C. Liu, James R. Graham, Stephane Charlot

We have measured K-band surface brightness fluctuations (SBFs) of 19 early-type galaxies in the Fornax cluster. Combining our results with published data, we find the absolute SBF magnitude Mbar_K = (-5.84)+(3.6)*[(V-I)-1.15]. The intrinsic cosmic scatter of Mbar_K appears to be larger than that of I-band SBFs. The discovery of a correlation between K-band S

H. Hees, J. Knoll

Within finite temperature field theory, we show that truncated non-perturbative self-consistent Dyson resummation schemes can be renormalized with local counter-terms defined at the vacuum level. The requirements are that the underlying theory is renormalizable and that the self-consistent scheme follows Baym''s $Φ$-derivable concept. The scheme gene

J. A. Sellwood

I give a very brief review of aspects of internal dynamics that affect the global shape of a galaxy, focusing on triaxiality, bars and warps. There is general agreement that large central masses can destroy triaxial shapes, but recent simulations of this process seem to suffer from numerical difficulties. Central black holes alone are probably not massive en

T. M. aliev, A. Ozpineci, M. Savci

Using the most general form of the interpolating currents of heavy baryons, the magnetic moments of heavy baryons "Lambda_Q (Q=b,c)" are calculated in framework of the light cone QCD sum rules. A comparison of our results on magnetic moments with the existing theoretical results calculated in various other frameworks are presented.

Ernest Ma, G. Rajasekaran

The three massless active (doublet) neutrinos may mix with two heavy and one \underline {light} sterile (singlet) neutrinos so that the induced masses and mixings among the former are able to explain the present data on atmospheric and solar neutrino oscillations. If the LSND result is also to be explained, one active neutrino mass eigenstate must mix with t

T. B. Pittman, B. C. Jacobs, J. D. Franson

It has previously been shown that probabilistic quantum logic operations can be performed using linear optical elements, additional photons (ancilla), and post-selection based on the output of single-photon detectors. Here we describe the operation of several quantum logic operations of an elementary nature, including a quantum parity check and a quantum enc

Amihay Hanany, Jan Troost

We analyze string theory backgrounds that include different kinds of orientifold planes and map out a natural correspondence to (twisted) affine Kac-Moody algebras. The low-energy description of specific BPS states in these backgrounds leads to a construction of explicit twisted magnetic monopole solutions on R^3 x S^1. These backgrounds yield new low-energy

J. J. van der Bij, Eugen Radu

Black hole solutions with nonspherical event horizon topology are shown to exist in an Einstein-Yang-Mills theory with negative cosmological constant. The main characteristics of the solutions are presented and differences with respect to the spherically symmetric case are studied. The stability of these configurations is also addressed.

A. Masiero, C. A. Scrucca, M. Serone, L. Silvestrini

Scherk-Schwarz gauge symmetry breaking of a D-dimensional field theory model compactified on a circle is analyzed. It is explicitly shown that forbidden couplings in the unbroken theory appear in the one-loop effective action only in a non-local way, implying that they are finite at all orders in perturbation theory. This result can be understood as a conseq

Philippe Pouliot

We generate by computer a basis of invariants for the fundamental representations of the exceptional Lie groups E(6) and E(7), up to degree 18. We discuss the relevance of this calculation for the study of supersymmetric gauge theories, and revisit the self-dual exceptional models. We study the chiral ring of G(2) to degree 13, as well as a few classical gro

P. Fosalba, O. Doré, F. R. Bouchet

We present an analytic approach to the estimation of beam asymmetry effects in CMB temperature and linear polarization anisotropy experiments. We derive via perturbative expansions simple and accurate results for the case of an elliptical Gaussian window. Our results are applied to investigate the effect of beam ellipticity in the estimation of full-sky pola

Thomas DeGrand

I use the technique of Hernandez, et al (hep-lat/0106011) to convert a recent calculation of the lattice-regulated quark condensate from an overlap action to a continuum-regulated number. I find Sigma(MSbar)(mu = 2 GeV) = (282(6) MeV)-cubed times (a-inverse/1766 MeV)-cubed from a calculation with the Wilson gauge action at beta=5.9.