January 2001 arXiv papers

Hungsoo Kim, D. K. Park, S. Tamaryan, H. J. W. Müller-Kirsten

In the context of $AdS/CFT$ correspondence the two Wilson loop correlator is examined at both zero and finite temperatures. On the basis of an entirely analytical approach we have found for Nambu-Goto strings the functional relation $d S_c^{(Reg)} / dL = 2 \pi k$ between Euclidean action $S_c$ and loop separation $L$ with integration constant $k$, which corr

Pierre Binétruy, Cédric Deffayet, David Langlois

We consider the homogeneous cosmological radion, which we define as the interbrane distance in a two brane and $Z_2$ symmetrical configuration. In a coordinate system where one of the brane is at rest, the junction conditions for the second (moving) brane give directly the (non-linear) equations of motion for the radion. We analyse the radion fluctuations an

Nima Arkani-Hamed, Thomas Gregoire, Jay Wacker

We present an explicit formulation of supersymmetric Yang-Mills theories from $\D=$ 5 to 10 dimensions in the familiar $\N=1,\D=4$ superspace. This provides the rules for globally supersymmetric model building with extra dimensions and in particular allows us to simply write down $\N=1$ SUSY preserving interactions between bulk fields and fields localized on

Reinhold A. Bertlmann, Beatrix C. Hiesmayr

We investigate Bell inequalities for neutral kaon systems from Phi resonance decay to test local realism versus quantum mechanics. We emphasize the unitary time evolution of the states, that means we also include all decay product states, in contrast to other authors. Only this guarantees the use of the complete Hilbert space. We develop a general formalism

F. Bigazzi

We perform here a critical analysis of some non-supersymmetric gravity solutions in Type 0B string theory. We first consider the most general configuration of parallel N electric and M magnetic D3-branes. The field theory living on their worldvolume is non-supersymmetric and non-conformal (if N is different from M) and has gauge group SU(N)XSU(M). We study t

E. L. Bratkovskaya

Detailed predictions for dilepton production from $p A$ reactions at SIS energies are presented within a semi-classical BUU transport model that includes the off-shell propagation of vector mesons nonperturbatively and calculates the width of the vector mesons dynamically. Different scenarios of in-medium modifications of vector mesons, such as collisional b

Gregory Brown, M. A. Novotny, Per Arne Rikvold

Numerical solutions of the Landau-Lifshitz-Gilbert micromagnetic model incorporating thermal fluctuations and dipole-dipole interactions (calculated by the Fast Multipole Method) are presented for systems composed of nanoscale iron pillars of dimension 9 nm x 9 nm x 150 nm. Hysteresis loops generated under sinusoidally varying fields are obtained, while the

H. J. de Vega, N. S'anchez

We provide a complete picture to the selfgravitating non-relativistic gas at thermal equilibrium using Monte Carlo simulations, analytic mean field methods (MF) and low density expansions. The system is shown to possess an infinite volume limit in the grand canonical (GCE), canonical (CE) and microcanonical (MCE) ensembles when(N, V) --> infinity, keeping N/

H. J. de Vega, N. S'anchez

We complete our study of the selfgravitating gas by computing the fluctuations around the saddle point solution for the three statistical ensembles. Although the saddle point is the same for the three ensembles, the fluctuations change from one ensemble to another. The zeroes of the fluctuations determinant determine the position of the critical points for e

M. A. Clayton, J. W. Moffat

The dynamical consequences of a bimetric scalar-tensor theory of gravity with a dynamical light speed are investigated in a cosmological setting. The model consists of a minimally-coupled self-gravitating scalar field coupled to ordinary matter fields in the standard way through the metric: $\metric_{μν}+B\partial_μϕ\partial_νϕ$. We show that in a universe w

C. Le Mouel

In the MSSM, we make a careful tree-level study of Charge and Color Breaking conditions in the plane $(H_2, \tilde{u}_L, \tilde{u}_R)$, focusing on the top quark scalar case. A simple and fast procedure to compute the VEVs of the dangerous vacuum is presented and used to derive a model-independent optimal CCB bound on $A_t$. This bound takes into account all

Matsuo Sato

We construct 1/8, 1/4, and 1/2 BPS solutions spanned by diagonal elements of U(N) constant fluxes in the 6+1 dimensional U(N) super Yang-Mills theory on T^6 with topological stability. These solutions represent BPS bound states of D0, D2, D4, and D6 branes. The consistency with the D-brane charge conservation implies that unstable D0-D2-D6-brane systems in a

Donam Youm

We study cosmologies in the Randall-Sundrum models, incorporating the possibility of time-varying speed of light and Newton's constant. The cosmologies with varying speed of light (VSL) were proposed by Moffat and by Albrecht and Magueijo as an alternative to inflation for solving the cosmological problems. We consider the case in which the speed of ligh

Jens Mund

The geometric action of modular groups for wedge regions (Bisognano-Wichmann property) is derived from the principles of local quantum physics for a large class of Poincare covariant models in d=4. As a consequence, the CPT theorem holds for this class. The models must have a complete interpretation in terms of massive particles. The corresponding charges ne

G. Akemann, P. H. Damgaard

Based on the AdS/CFT correspondence, string theory has given exact predictions for circular Wilson loops in U(N) ${\cal N}=4$ supersymmetric Yang-Mills theory to all orders in a 1/N expansion. These Wilson loops can also be derived from Random Matrix Theory. In this paper we show that the result is generically insensitive to details of the Random Matrix Theo

Richard L. Hall, Wolfgang Lucha, F. F. Schoberl

We study the spectrum of the spinless-Salpeter Hamiltonian H = β\sqrt{m^2 + p^2} + V(r), where V(r) is an attractive central potential in three dimensions. If V(r) is a convex transformation of the Coulomb potential -1/r and a concave transformation of the harmonic-oscillator potential r^2, then upper and lower bounds on the discrete eigenvalues of H can be

Kingman Cheung, Otto C. W. Kong

Starting from the new sources of $LL$- and $LR$- scalar (slepton) mixings due to R-parity violation, we discuss the structure of lepton-flavor violation focusing on the radiative decay of muon into electron. Using an optimal parametrization, we give the general formulae for the one-loop contributions. from which we discuss all combinations of R-parity violat

A. van Heukelum, G. T. Barkema, R. H. Bisseling

The cage model for polymer reptation, proposed by Evans and Edwards, and its recent extension to model DNA electrophoresis, are studied by numerically exact computation of the drift velocities for polymers with a length L of up to 15 monomers. The computations show the Nernst-Einstein regime (v ~ E) followed by a regime where the velocity decreases exponenti

Y. C. Liang, Edward Teo

We present a technique that can be used to generate a static, axisymmetric solution of the Einstein-Maxwell-Dilaton equations from a stationary, axisymmetric solution of the vacuum Einstein equations. Starting from the Kerr solution, Davidson and Gedalin have previously made use of this technique to obtain a pair of oppositely charged, extremal dilatonic bla

S. Giusto, M. B. Halpern

Using a Hamiltonian approach, we construct the classical and quantum theory of open WZW strings on a strip. (These are the strings which end on WZW branes.) The development involves non-abelian generalized Dirichlet images in an essential way. At the classical level, we find a new non-commutative geometry in which the equal-time coordinate brackets are non-z

Lorenzo Cornalba, Ricardo Schiappa

We investigate the deformation of D-brane world-volumes in curved backgrounds. We calculate the leading corrections to the boundary conformal field theory involving the background fields, and in particular we study the correlation functions of the resulting system. This allows us to obtain the world-volume deformation, identifying the open string metric and

S. L. Bud'ko, G. Lapertot, C. Petrovic, C. E. Cunningham

We report the preparation method of, and boron isotope effect for MgB$_2$, a new binary intermetallic superconductor with a remarkably high superconducting transition temperature $T_c$($^{10}$B) = 40.2 K. Measurements of both temperature dependent magnetization and specific heat reveal a 1.0 K shift in $T_c$ between Mg$^{11}$B$_2$ and Mg$^{10}$B$_2$. Whereas

Luis P. Chimento, Alejandro S. Jakubi, Norberto A. Zuccala

We investigate the simplest quintessence dissipative dark matter attractor cosmology characterized by a constant quintessence baryotropic index and a power--law expansion. We show a class of accelerated coincidence--solving attractor solutions converging to this asymptotic behavior. Despite its simplicity, such a ``superattractor'' regime provides a

Michael E. Peskin, James D. Wells

The fit of precision electroweak data to the Minimal Standard Model currently gives an upper limit on the Higgs boson mass of 170 GeV at 95% confidence. Nevertheless, it is often said that the Higgs boson could be much heavier in more general models. In this paper, we critically review models that have been proposed in the literature that allow a heavy Higgs

N. Lehner, K. R. Sembach, P. L. Dufton, W. R. J. Rolleston

We present ultraviolet and optical spectra of DI 1388, a young star in the Magellanic Bridge, a region of gas between the Small and Large Magellanic Clouds. The data have signal-to-noise ratios of 20 to 45 and a spectral resolution of 6.5 km/s. Interstellar absorption by the Magellanic Bridge at v_LSR = 200 km/s is visible in the lines of C I, C II,C II*, C

A. B. Matsko, I. Novikova, M. O. Scully, G. R. Welch

We show that the effective decay rate of Zeeman coherence, generated in a Rb87 vapor by linearly polarized laser light, increases significantly with the atomic density. We explain this phenomenon as the result of radiation trapping. Our study shows that radiation trapping must be taken into account to fully understand many electromagnetically induced transpa

Y. G. A Pierseaux

Einstein's reply to Weyl about the importance in General Relativity of the identity of the sources of spectral lines is well know. We show that, already in Special Relavitity, Einstein's definition of the unit of time from the frequency of atomic emission is deeply incompatible with Poincare's classical conception of time in his special relativit

A. B. Klimov, L. L. Sanchez-Soto, J. Delgado

We find an effective Hamiltonian describing the process of second-harmonic generation in the far-off resonant limit. We show that the dynamics of the fundamental mode is governed by a Kerrlike Hamiltonian. Some dynamical consequences are examined.

Erasmo Recami

In this article (after some brief theoretical considerations) a bird-eye view is presented -with the help of nine figures- of the various experimental sectors of physics in which Superluminal motions seem to appear. In particular, a panorama is presented of the experiments with evanescent waves and/or tunnelling photons, and with the "localized Superlumi

F. Hammache, G. Bogaert, P. Aguer, C. Angulo

We have measured the cross section of the 7Be(p,gamma)8B reaction for E_cm = 185.8 keV, 134.7 keV and 111.7 keV using a radioactive 7Be target (132 mCi). Single and coincidence spectra of beta^+ and alpha particles from 8B and 8Be^* decay, respectively, were measured using a large acceptance spectrometer. The zero energy S factor inferred from these data is

V. Eckardt, T. Eggert, H. Fessler, H. Hümmler

The principles of the calibration of a time projection chamber with radioactive Krypton-83 are explained. The calculation of gain correction factors and the methods of obtaining a precise energy calibration are illustrated. The properties and advantages of \nuc{83m}{Kr} are summarized and compared to other radioactive calibration sources. It was shown that t

Tetsu Masuda, Yasuhiro Ohta, Kenji Kajiwara

We give an explicit determinant formula for a class of rational solutions of the Painlevé V equation in terms of the universal characters.

J. de Gier, V. Korepin

We consider the six-vertex model with domain wall boundary conditions. We choose the inhomogeneities as solutions of the Bethe Ansatz equations. The Bethe Ansatz equations have many solutions, so we can consider a wide variety of inhomogeneities. For certain choices of the inhomogeneities we study arrow correlation functions on the horizontal line going thro

Michael K. Murray

I survey the theory of Bogomolny monopoles and the various approaches to their study. These include the spectral curve, Nahm correspondence and rational maps.

A. B. Aleksandrov, V. V. Peller

We study the problem of characterizing Hankel-Schur multipliers and Toeplitz-Schur multipliers of Schatten-von Neumann class $\bS_p$ for $0<p<1$. We obtain various sharp necessary conditions and sufficient conditions for a Hankel matrix to be a Schur multiplier of $\bS_p$. We also give a characterization of the Hankel-Schur multipliers of $\bS_p$ whose symbo

J. Colliander, M. Keel, G. Staffilani, H. Takaoka

We prove that the 1D Schrödinger equation with derivative in the nonlinear term is globally well-posed in $H^{s}$, for $s>2/3$ for small $L^{2}$ data. The result follows from an application of the ``I-method&#39;&#39;. This method allows to define a modification of the energy norm $H^{1}$ that is ``almost conserved&#39;&#39; and can be used to perform an ite

J. Colliander, M. Keel, G. Staffilani, H. Takaoka

The initial value problem for the Korteweg-deVries equation on the line is shown to be globally well-posed for rough data. In particular, we show global well-posedness for initial data in H^s({\mathbb{R}), -3/10<s.

V. -B. K. Rogov

The q-Bessel-Macdonald functions of kinds 1, 2 and 3 are considered. Their representations by classical integral are constructed.

Michael K. Murray, Daniel Stevenson

We give a characterisation of central extensions of a Lie group G by the non-zero complex numbers in terms of a differential two-form on G and a differential one-form on GxG. This is applied to the case of the central extension of the loop group.

Mu-Fa Chen

This paper surveys the main results obtained during the period 1992-1999 on three aspects mentioned at the title. The first result is a new and general variational formula for the lower bound of spectral gap (i.e., the first non-trivial eigenvalue) of elliptic operators in Euclidean space, Laplacian on Riemannian manifolds or Markov chains (§1). Here, a prob

Young-Hoon Kiem

We show by studying the symplectic geometry of the extended moduli space that the intersection cohomology of the representation space $Hom(π_1(Σ),G)/G$ for a simply connected compact Lie group $G$ is naturally embedded into the $G$ equivariant cohomology of $Hom(π_1(Σ),G)$ where $Σ$ is a closed Riemann surface. This enables us to compute the intersection coh

Young-Hoon Kiem, Jonathan Woolf

Let $M$ be a proper Hamiltonian $K$-space with proper moment map $μ$. The symplectic quotient $X=μ^{-1}(0)/K$ is in general a singular stratified space. In this paper we first generalize the Kirwan map to this symplectic setting which maps the $K$ equivariant cohomology of $μ^{-1}(0)$ to the middle perversity intersection cohomology $IH^*(X)$. Next, we show

Xiaoping Xu

Poisson superpair is a pair of Poisson superalgebra structures on a super commutative associative algebra, whose any linear combination is also a Poisson superalgebra structure. In this paper, we first construct certain linear and quadratic Poisson superpairs over a finite-dimensional or semi-finitely-filtered polarized $\Bbb{Z}_2$-graded associative algebra

Dominic Joyce

This is the second in a series of papers constructing explicit examples of special Lagrangian submanifolds in C^m. The first paper was math.DG/0008021, which studied special Lagrangian m-folds with large symmetry groups. The third is math.DG/0010036, which uses ideas from this paper to construct families of special Lagrangian 3-folds in C^3. This paper descr

I. Martin, J. Ovalle, A. Restuccia

It is shown that a double compactified D=11 supermembrane with non trivial wrapping may be formulated as a symplectic non-commutative gauge theory on the world volume. The symplectic non commutative structure is intrinsically obtained from the symplectic 2-form on the world volume defined by the minimal configuration of its hamiltonian. The gauge transformat

Jonathan M. Evans

Local commuting charges in sigma-models with classical Lie groups as target manifolds are shown to be related to the conserved quantities appearing in the Drinfeld-Sokolov (generalized mKdV) hierarchies. Conversely, the Drinfeld-Sokolov construction can be used to deduce the existence of commuting charges in these and in wider classes of sigma-models, includ

G. W. Gibbons, C. A. R. Herdeiro

We derive a Melvin Universe type solution describing a magnetic field permeating the whole Universe in gravity minimally coupled to any non-linear electromagnetic theory, including Born-Infeld Theory. For a large set of non-linear electrodynamics theories, our solution is complete and non-singular, as long as the magnetic field is sub-critical. We examine so

Kiyoshi Higashijima, Naoto Yokoi

We study the spontaneous Lorentz symmetry breaking in a field theoretical model in (2+1)-dimension, inspired by string theory. This model is a gauge theory of an anti-symmetric tensor field and a vector field (photon). The Nambu-Goldstone (NG) boson for the spontaneous Lorentz symmetry breaking is identified with the unphysical massless photon in the covaria

Ernest Ma

The Newton-Wu conditions for the cancellation of quadratic divergences in a class of two-Higgs-doublet models are analyzed as to how they may be satisfied with a typical extension of the Standard Model of particle interactions.

Shinya Kanemura, Stefano Moretti, Kosuke Odagiri

We discuss single charged Higgs boson production from $e^+e^-$ annihilation at next generation linear colliders. They can be important to study the phenomenology of charged Higgs bosons, especially when charged Higgs bosons are too heavy to be produced by the pair production mechanism. Cross sections for various single production processes are evaluated at t

Aseshkrishna Datta, Abdelhak Djouadi, Jean-Loic Kneur

We discuss the production at $e^+e^-$ colliders of Higgs bosons in association with both the scalar leptons and the lightest neutralinos in the Minimal Supersymmetric extension of the Standard Model. While the rates for associated Higgs production with neutralinos and first/second generation sleptons are rather tiny, the cross section for the production of t

Gregory W. Anderson, Tomas Blazek

$E_6$ is an attractive group for unification model building. However, the complexity of a rank 6 group makes it non-trivial to write down the structure of higher dimensional operators in an $E_6$ theory in terms of the states labeled by quantum numbers of the Standard Model gauge group. In this paper, we show the results of our computation of the Clebsch-Gor

M. A. Kimber, A. D. Martin, M. G. Ryskin

We describe how to calculate the parton distributions $f_a(x, k_t^2, μ^2)$, unintegrated over the parton transverse momentum $k_t$, from auxiliary functions $h_a(x, k_t^2)$, which satisfy single-scale evolution equations. The formalism embodies both DGLAP and BFKL contributions, and accounts for the angular ordering which comes from coherence effects in gluo

E. N. Argyres, A. F. W. van Hameren, R. H. P. Kleiss, C. G. Papadopoulos

A study of zero-dimensional theories, based on exact results, is presented. First, relying on a simple diagrammatic representation of the theory, equations involving the generating function of all connected Green&#39;s functions are constructed. Second, exact solutions of these equations are obtained for several theories. Finally, renormalization is carried

Tran N. Truong

The solution of the Muskhelishvili-Omnes Integral Equation is ambiguous by a real polynomial. The coefficients of this polynomial can be fixed either by the knowledge of the low energy parameters or by the asymptotic behavior of the form factor. The role of the contact terms of the low energy effective Lagrangian is explicitly analysed.

E. Gotsman, E. Levin, M. Lublinsky, U. Maor

These notes are a summary of our predictions for the new THERA project, related to deep inelastic scattering in the region of ultra low $x$ ($x \to 10^{-7}$). We collect here predictions that satisfy two criteria (i) they do not depend on specific features of the model that we have to use to estimate a possible effect; and (ii) they do not contradict the HER

Biswanath Layek, Soma Sanyal, Ajit M. Srivastava

Cosmic strings moving through matter produce wakes where density is higher than the background density. We investigate the effects of such wakes occurring at the time of a first order quark-hadron transition in the early universe and show that they can lead to separation of quark-gluon plasma phase in the wake region, while the region outside the wake conver

E. I. Ivanov

An amplitude analysis of an exclusive sample of 5765 events from the reaction $π^{-} p \to η^{\prime} π^- p$ at 18 GeV/c is described. The $η^{\prime} π^-$ production is dominated by natural parity exchange and by three partial waves: those with $J^{PC} = 1^{-+}, 2^{++},$ and $4^{++}$. A mass-dependent analysis of the partial-wave amplitudes indicates the pr

Ian G Moss, Wade Naylor

A diagramatic heat kernel expansion technique is presented. The method is especially well suited to the small-derivative expansion of the heat kernel, but it can also be used to reproduce the results obtained by the approach known as covariant perturbation theory. The new technique gives an expansion for the heat kernel at coincident points. It can also be u

Filippo Giraldi, Paolo Grigolini

Entanglement is the fundamental quantum property behind the now popular field of quantum transport of information. This quantum property is incompatible with the separation of a single system into two uncorrelated subsystems. Consequently, it does not require the use of an additive form of entropy. We discuss the problem of the choice of the most convenient

Bernard Deconinck, Bela A. Frigyik, J. Nathan Kutz

The cubic nonlinear Schrodinger equation with repulsive nonlinearity and elliptic function potential in two-dimensions models a repulsive dilute gas Bose--Einstein condensate in a lattice potential. A family of exact stationary solutions is presented and its stability is examined using analytical and numerical methods. All stable trivial-phase solutions are

R. Schumann

By use of the conservation laws a four-site Hubbard model coupled to a particle bath within an external magnetic field in z-direction was diagonalized. The analytical dependence of both the eigenvalues and the eigenstates on the interaction strength, the chemical potential and magnetic field was calculated. It is demonstrated that the low temperature behavio

Rashmi Ray

In this article, we shall focus on the collective dynamics of the fermions in a $ν= 1$ quantum Hall droplet. Specifically, we propose to look at the quantum Hall ferromagnet. In this system, the electron spins are ordered in the ground state due to the exchange part of the Coulomb interaction and the Pauli exclusion principle. The low energy excitations are

David L. C. Chan, David Eliezer, Ian I. Kogan

We present results of numerical analysis of several simple models for the microstructure of a double auction market without intermediaries which were introduced in cond-mat/9808240. We perform computer simulations of the minimal model in order to verify liquidity scaling laws. A logarithmic correction to the scaling law for midmarket variance is observed, bu

R. Raimondi, M. Leadbeater, P. Schwab, E. Caroti

It is shown that the spin-orbit coupling due to structure inversion asymmetry leads to a characteristic anisotropy in the magnetoconductance of two-dimensional metals. Relevance for recent experiments is discussed.

N. S. Skantzos, J. van Mourik, A. C. C. Coolen

We propose and solve a simple model describing secondary structure formation in random hetero-polymers. It describes monomers with a combination of one-dimensional short-range interactions (representing steric forces and hydrogen bonds) and infinite range interactions (representing polarity forces). We solve our model using a combination of mean field and ra

H. Portales, E. Duval, L. Saviot, M. Fujii

Raman scattering experiments from silver nanocrystals embedded in films of amorphous silica are reported. In addition to the low-frequency peak due to vibrational quadrupolar modes, a broadband is observed in the high-frequency range, with a maximum at about 1000 $cm^{-1}$. The linear dependence of the position of this maximum on the inverse cluster radius i

Yu. M. Zinoviev

The correlation functions are calculated for the three - dimensional Z_2 electrodynamics for the particular values of the ineraction energies and for the free boundary conditions.

Ranjan Chaudhury, Samir K. Paul

An effective theory for quantum spin system in low dimension is constructed in the finite-q regime. It is shown that there are field configurations for which Wess-Zumino term contributes to the partition functions as topological term for ferromagnet as well as antiferromagnet in both one and two dimensional lattice,in contrast to the long wave length regime.

A. Harju

The two-dimensional Hubbard model is studied using the variational quantum Monte Carlo technique with Gutzwiller-type variational wave functions. In addition to the simple one-site correlated Gutzwiller wave function, we use a form with correlation between electrons on nearest- and next-nearest-neighbor sites. We show that the stochastic gradient approximati

B. Sriram Shastry, Abhishek Dhar

We present the exact solution for a set of nonlinear algebraic equations $\frac{1}{z_l}= πd + \frac{2 d}{n} \sum_{m \neq l} \frac{1}{z_l-z_m}$. These were encountered by us in a recent study of the low energy spectrum of the Heisenberg ferromagnetic chain \cite{dhar}. These equations are low $d$ (density) ``degenerations&#39;&#39; of more complicated transce

Michael Brunner, Sylvain Capponi, Fakher F. Assaad, Alejandro Muramatsu

The dynamics of a single hole in the t-J model on two- (2LL) and three- (3LL) leg ladders is studied using a recently developed quantum Monte Carlo algorithm. For the 2LL it is shown that in addition to the most pronounced features of the spectral function, well described by the limit of strong coupling along the rungs, a clear shadow band appears in the ant

Eric P Rubenstein

Stellar flares 100-10^7 times more energetic than the most powerful solar flares have been detected from 9 normal F and G main sequence stars (Schaefer, King & Deliyannis 2000). Although these stars are not in close binary systems, their superflares show a remarkable similarity to the large stellar flares observed on RS Canum Venaticorum binary systems. Such

Steve B. Howell, David R. Ciardi

Infrared spectroscopic observations of LL Andromedae and EF Eridani are presented. Our K band spectrum of LL Andromedae reveals the presence of methane absorption in the secondary star indicating an effective temperature less than 1300K, similar to a &#34;T&#34; type methane brown dwarf. The secondary star in EF Eridani is seen to be warmer with an effective

C. S. Froning, E. L. Robinson

We measured the near-infrared orbital light curve of the black hole binary A0620-00 in 1995 and 1996. The light curves show an asymmetric, double-humped modulation with extra emission in the peak at orbital phase 0.75. There were no significant changes in the shape of the light curve over the one-year observation period. There were no sharp dips in the light

Svetlana G. Jorstad, Alan P. Marscher, John R. Mattox, Ann E. Wehrle

We present the results of a program to monitor the structure of the radio emission in 42 $γ$-ray bright blazars (31 quasars and 11 BL Lac objects) with the VLBA at 43, 22, and occasionally 15 and 8.4 GHz, over the period from November 1993 to July 1997. We determine proper motions in 33 sources and find that the apparent superluminal motions in $γ$-ray sourc

Michiel R. Hogerheijde

Evidence for a transitional stage in the formation of a low-mass star is reported, intermediate between the fully embedded and the T Tauri phases. Millimeter aperture synthesis observations in the HCO+ J=1-0 and 3-2, HCN 1-0, 13CO 1-0, and C18O 1-0 transitions reveal distinctly different velocity fields around two embedded, low-mass young stellar objects. Th

Andrew W. Steiner, Madappa Prakash, James M. Lattimer

Neutrino opacities important in the evolution of a proto-neutron star containing quark matter are studied. The results for pure quark matter are compared with limiting expressions previously derived, and are generalized to the temperatures, neutrino degeneracies and lepton contents encountered in a proto-neutron star&#39;s evolution. We find that the appeara

Daniele Fargion

The discover of Ultra High Energy Neutrino of astrophysical nature may be already reached. Indeed upward and horizontal tau Air-showers emerging from the Earth crust or mountain chains offer the best and most powerful signal of Ultra High Energy UHE neutrinos nu_tau}, barν_tau and barν_e at PeV and higher energy. The multiplicity in tau Air-showers secondary

Haiguang Xu, Guangxue Jin, Xiang-Ping Wu

We present a new investigation of the mass-temperature (\MTrelation) relation of 22 nearby clusters based on the analysis of their ROSAT X-ray surface brightness profiles ($S_{X}(r)$) and their ASCA emission weighted temperatures. Two methods of the cluster mass estimations are employed and their results are compared: (1) the conventional $β$ model for gas d

Karim A. Malik

After introducing gauge-invariant cosmological perturbation theory we give an improved set of governing equations for multiple fluids including energy transfer. Having defined adiabatic and entropic perturbations we derive the ``conservation law&#39;&#39; for the curvature perturbation on large scales using only the energy conservation equation. We then inve

Nissim Kanekar, T. Padmanabhan

We use non-linear scaling relations (NSRs) to investigate the effects arising from the existence of negative correlations on the evolution of gravitational clustering in an expanding universe. It turns out that such anti-correlated regions have important dynamical effects on {\it all} scales. In particular, the mere existence of negative values for the linea

Andreu Alibes, Javier Labay, Ramon Canal

A LiBeB evolution model including Galactic Cosmic Ray nucleosynthesis, the $ν$-process, novae, AGB and C-stars is presented. We have included Galactic Cosmic Ray Nucleosynthesis (GCRN) in a complete Chemical Evolution Model that takes into account 76 stable isotopes from hydrogen to zinc. Any successful LiBeB evolution model should also be compatible with ot

Sydney A. Barnes, Sabatino Sofia, Marc. H. Pinsonneault

The simultaneous presence of both the so-called `ultra-fast rotators&#39; and slowly rotating stars among the solar-type stars ($\sim 0.6-1.2 M_{\odot}$) in the same young star clusters has been a puzzle in the field of stellar rotation. No model to date has been able to explain both by a single mechanism intrinsic to the star and questions about the appropr

Paolo Lipari

New measurements of the cosmic ray fluxes (p, e+, e- and Helium) performed by the Alpha Magnetic Spectrometer (AMS) during a ten days flight of space shuttle have revealed the existence of significant fluxes of particles below the geomagnetic cutoff. These fluxes exhibit a number of remarkable properties, such as a He-3/He-4 ratio of order ~10, an e+/e- rati

Emi Miyata, Hiroshi Tsunemi

We performed spectroscopic X-ray observations of the eastern and northern regions of the Cygnus Loop with the ASCA observatory. The X-ray surface brightness of these regions shows a complex structure in the ROSAT all-sky survey image. We carried out a spatially-resolved analysis for both regions and found that $kT_{\rm e}$ did not increase toward the center

Hiroshi Tsunemi, Koji Mori, Emi Miyata, Christopher Baluta

The position accuracy of X-ray photons on a CCD detector is generally believed to be limited by the CCD pixel size. While this is true in general, the position accuracy for X-ray events which deposit charge in more than one pixel can be better than that of the CCD pixel size. Since the position uncertainty for corner events is much better than the pixel size

C. Maraston, M. Kissler-Patig, J. P. Brodie, P. Barmby

We have extended the study of the young star clusters observed in the merger remnant galaxy NGC 7252 by obtaining K band photometry for these clusters. Our K band data significantly complement the optical photometry and spectroscopy in the literature: K band data are fundamental to study the Asymptotic Giant Branch (AGB) population of these clusters, since t

Tsutomu T. Takeuchi, Ryohei Kawabe, Kotaro Kohno, Koichiro Nakanishi

We investigate what we can learn about galaxy formation and evolution from the data which will be obtained by the forthcoming large submillimeter/millimeter facilities, mainly by the Atacama Submillimeter Telescope Experiment (ASTE) and the Atacama Large Millimeter Array/Large Millimeter and Submillimeter Array (ALMA/LMSA). We first calculate the source coun

O. Saavedra, L. Jones

Cosmic rays physics is currently being studied with rather sophisticated detectors running in a variety of experimental conditions and atmospheric depths around the world. In this paper we describe the reasons why cosmic ray physics experiments at high altitudes like Chacaltaya are so important for resolving some of the open problems in cosmic physics. A dis

Andreas Burkert, Thorsten Naab

High-resolution numerical simulations of galaxy mergers are analysed. The global structure and isophotal shapes of the merger remnants are in good agreement with the observations. Whereas equal-mass mergers lead to anisotropic, boxy ellipticals, unequal-mass mergers result in disky and isotropic systems. The line-of-sight velocity distributions show small de

S. Schippers, A. Mueller, G. Gwinner, J. Linkemann

The low energy C IV dielectronic recombination (DR) rate coefficient associated with 2s-2p Delta n=0 excitations of this lithiumlike ion has been measured with high energy-resolution at the heavy-ion storage-ring TSR of the Max-Planck-Institut fuer Kernphysik in Heidelberg, Germany. The experimental procedure and especially the experimental detection probabi

J. V. Narlikar, R. G. Vishwakarma, G. Burbidge, F. Hoyle

In this paper we show that, within the framework of the QSSC, the small scale deviations on angular scales $\lesssim 1^{0}$ expected in the MBR are due to inhomogeneities in the distribution of galaxies and clusters. It is shown how these can be estimated on the galaxy-cluster-supercluster scale at the epoch of redshift $\sim 5$ when the universe was last pa

Robert E. Rutledge

Previous work on the emission from isolated old neutron stars (IONS) accreting the inter-stellar medium (ISM) focussed on gravitational capture - Bondi accretion. We propose a new class of sources which accrete via magnetic interaction with the ISM. While for the Bondi mechanism, the accretion rate decreases with increasing NS velocity, in magnetic accretors

Cristiano Palomba

We consider the emission of gravitational waves in the two proposed models for the collapse of a massive star to a black hole: the prompt collapse, in which nearly all the star collapses to a black hole in a dynamical time scale, and the delayed collapse, in which a light black hole, or a neutron star, which subsequently accretes matter, forms due to the fal

K. Abazajian, G. M. Fuller, M. Patel

We calculate the incoherent resonant and non-resonant scattering production of sterile neutrinos in the early universe. We find ranges of sterile neutrino masses, vacuum mixing angles, and initial lepton numbers which allow these species to constitute viable hot, warm, and cold dark matter (HDM, WDM, CDM) candidates which meet observational constraints. The

Diego Cordoba, Charles Fefferman

We povide a test for numerical simulations for the collapse of regular tubes carried by a 3D incompressible flow. In particular, we obtain necessary conditions for 3D Euler to have a vortex tube collapse in finite time.

Kathryn V. Johnston, Penny D. Sackett, James S. Bullock

We examine the detectability and interpretation of debris trails caused by satellite disruption in external galaxies using semi-analytic approximations for the dependence of streamer length, width and surface brightness on satellite and primary galaxy characteristics. The semi-analytic method is tested successfully against N-body simulations and then applied

G. D. Sanders, C. J. Stanton, Chang-Sub Kim

A microscopic theory for the generation and propagation of coherent LA phonons in pseudomorphically strained wurzite (0001) InGaN/GaN multi-quantum well (MQW) p-i-n diodes is presented. The generation of coherent LA phonons is driven by photoexcitation of electron-hole pairs by an ultrafast Gaussian pump laser and is treated theoretically using the density m

Thomas Gajdosik

In this talk I want to present questions that remained unclear to me in the last years. These questions concern the Electric Dipole Moments of electron and neutron and the way people exclude regions of parameter space.