October 1997 arXiv papers — page 6

D. Barrado y Navascues, J. R. Stauffer, S. Randich

We have studied dF-dK and dM stars belonging to Praesepe in order to determine membership via radial velocities and to compare several stellar properties, such as X-ray luminosities, H$α$ equivalent width, etc, between this cluster and Hyades, which have similar age. We show that all properties are analogous in both clusters except the distribution of Lx. Th

T. Tanimori, K. Sakurazawa, S. A. Dazeley, P. G. Edwards

Gamma rays with energies greater than 7 TeV from the Crab pulsar/nebula have been observed at large zenith angles, using the Imaging Atmospheric Technique from Woomera, South Australia. CANGAROO data taken in 1992, 1993 and 1995 indicate that the energy spectrum extends up to at least 50 TeV, without a change of the index of the power law spectrum. The obser

Raffaele G. Gratton

HIPPARCOS satellite parallaxes for 22 metal-poor field horizontal branch stars with Vo<9 are used to derive their absolute magnitude. The weighted mean value is Mv=+0.69+/-0.10 for an average metallicity of [Fe/H]=-1.41; a somewhat brighter average magnitude of Mv=+0.60+/-0.12 for an average metallicity of [Fe/H]=-1.51 is obtained eliminating HD17072, that m

B. Ratra, K. Ganga, N. Sugiyama, G. S. Tucker

We use data from the White Dish experiment to set limits on cosmic microwave background radiation anisotropies in open and spatially-flat-Lambda cold dark matter cosmogonies. We account for the White Dish calibration uncertainty, and marginalize over the offset and gradient removed from the data. Our 2-sigma upper limits are larger than those derived previou

Matthew Colless, Brian Boyle

We report on the 2dF Galaxy and QSO Redshift Surveys now in progress with the Two Degree Field facility at the Anglo-Australian Observatory. We describe the 2dF instrumentation, outline the scientific aims of the surveys and their current status, and present some initial results.

T. J. Pearson, I. W. A. Browne, D. R. Henstock, A. G. Polatidis

The Caltech-Jodrell Bank VLBI surveys of bright extragalactic radio sources north of declination 35 deg were carried out between 1990 and 1995 using the Mark-II system, achieving images with a resolution of about 1 mas at 5 GHz. The CJ1 survey (together with the older `PR&#39; survey) includes 200 objects with 5 GHz flux density greater than 0.7 Jy; the CJ2

H. Andernach, Erik Tago

We present an update of our compilation of measured redshifts of galaxy clusters in the all-sky Abell catalog. In the last 7 years the number of ACO clusters with measured z has doubled to now ~2100, but still ~56% of these are based on only 1 or 2 measured member galaxies. Our October 1997 version gives 2247 redshifts (including components or line-of-sight

M. Kapranov

It was suggested on several occasions by Deligne, Drinfeld and Kontsevich that all the moduli spaces arising in the classical problems of deformation theory should be extended to natural &#34;derived&#34; moduli spaces which are always smooth in an appropriate sense and whose tangent spaces involve the entire cohomology of the sheaf of infinitesimal automorp

Michael R. Douglas, Hirosi Ooguri

Recently Sen and Seiberg gave a prescription for constructing the matrix theory in any superstring background. We use their prescription to test the finite N matrix theory conjecture on an ALE space. Based on our earlier work with Shenker, we find a sharper discrepancy between matrix theory computation and supergravity prediction. We discuss subtleties in th

Ricardo Troncoso, Jorge Zanelli

Locally supersymmetric systems in odd dimensions whose Lagrangians are Chern-Simons forms for supersymmetric extensions of anti-de Sitter gravity are discussed. The construction is illustrated for D=7 and 11. In seven dimensions the theory is an N=2 supergravity whose fields are the vielbein ($e_{\mu}^{a}$), the spin connection ($\omega_{\mu}^{ab}$), two gra

David G. Shelton, David Sénéchal

We study a system of two Tomonaga-Luttinger models coupled by a small transverse hopping (a two-chain ladder). We use Abelian and non-Abelian bosonisation to show that the strong coupling regime at low energies can be described by an SO(5)$_1$ WZW model (or equivalently 5 massless Majorana fermions) deformed by symmetry breaking terms that nonetheless leave

David P. DiVincenzo, Daniel Loss

We discuss a few current developments in the use of quantum mechanically coherent systems for information processing. In each of these developments, Rolf Landauer has played a crucial role in nudging us and other workers in the field into asking the right questions, some of which we have been lucky enough to answer. A general overview of the key ideas of qua

Stéphane Pairault, David Sénéchal, A. -M. S. Tremblay

A strong-coupling expansion for models of correlated electrons in any dimension is presented. The method is applied to the Hubbard model in $d$ dimensions and compared with numerical results in $d=1$. Third order expansion of the Green function suffices to exhibit both the Mott metal-insulator transition and a low-temperature regime where antiferromagnetic c

Edward F. Brown

Abundance measurements of the light elements lithium, beryllium, and boron are playing an increasingly important role in the study of stellar physics. Because these elements are easily destroyed in stars at temperatures 2--4 million K, the abundances in the surface convective zone are diagnostics of the star&#39;s internal workings. Standard stellar models c

Ernest Ma, D. P Roy, Jose Wudka

If the charged Higgs boson H+ exists with mh < mt + mb, the conventional expectation is that it will decay dominantly into c s-bar and tau+ nu-tau. However, the three-body decay mode H+ --> W+ b b-bar is also present and we show that it becomes very important in the low tan(beta) region for mh >~ 140 GeV. We explore its phenomenological implications for the

L. Cooper, I. I. Kogan, R. J. Szabo

We describe mirror symmetry in N=2 superconformal field theories in terms of a dynamical topology changing process of the principal fiber bundle associated with a topological membrane. We show that the topological symmetries of Calabi-Yau sigma-models can be obtained from discrete geometric transformations of compact Chern-Simons gauge theory coupled to char

Edward F. Brown, Lars Bildsten

We investigate the atmosphere, ocean, and crust of neutron stars accreting at rates sufficiently high (typically in excess of the local Eddington limit) to stabilize the burning of accreted hydrogen and helium. For hydrogen-rich accretion at global rates in excess of 10^-8 solar masses per year (typical of a few neutron stars), we discuss the thermal state o

Luis Bento

It is proved that true Goldstone bosons develop coherent fields whenever the associated charges of the matter particles are not conserved in a macroscopic scale. The sources of the Goldstone fields are the time rates of quantum number violation. The case of neutrino flavour oscillations is studied with application to Supernovae. It is shown that if the Lepto

Joachim Brand, Lorenz S. Cederbaum

We present an approximation scheme for the calculation of the principal excitation energies and transition moments of finite many-body systems. The scheme is derived from a first order approximation to the self energy of a recently proposed extended particle-hole Green&#39;s function. A hermitian eigenvalue problem is encountered of the same size as the well

Paul B. Slater

Hubner&#39;s formula for the Bures (statistical distance) metric is applied to both a one-parameter and a two-parameter series (n=2,...,7) of sets of 2^n x 2^n density matrices. In the doubly-parameterized series, the sets are comprised of the n-fold tensor products --- corresponding to n independent, identical quantum systems --- of the 2 x 2 density matric

Frank E. Close

The production of $J^{PC} = 1^{++},0^{-+}$ and $2^{-+}$ mesons in double tagged $e^+e^- \to e^+e^-R$ is calculated and found to have the same polarisation and dynamical characteristics as observed in $pp \to ppR$. Implications for the spin structure of the Pomeron are considered. Production of $0^{++},2^{++}$ mesons in these two processes may enable the dyna

Y. Tanushi, Y. Nakahara, S. Saito, M. Uehara

We calculate the spin-dependent polarizability of the nucleon in the Skyrme model. The result is compared with that of a heavy baryon chiral perturbation theory(HBChPT), and is shown to be the same as that of HBChPT up to the $Δ$-pole terms in the narrow width limit of the $Δ$ state and with the experimental physical constants. The effect of the $Δ+π$ channe

L. B. Leinson, A. Perez

We have considered collective effects in $ν\barν$ synchrotron radiation from an ultrarelativistic degenerate electron gas in neutron stars with strong magnetic fields. For this problem we apply a calculation method which explicitly makes use of the fact that the radiating electron moves semi-classically, but takes into account the interaction among particles

Anna Opanowicz

All bialgebra structures for centrally extended Galilei algebra are classified. The corresponding Lie-Poisson structures on centrally extended Galilei group are found.

S. Chaturvedi

We discuss the symmetric homogeneous polynomial solutions of the generalized Laplace&#39;s equation which arises in the context of the Calogero-Sutherland model on a line. The solutions are expressed as linear combinations of Jack polynomials and the constraints on the coefficients of expansion are derived. These constraints involve generalized binomial coef

Ross H. McKenzie, J. S. Qualls, S. Y. Han, J. S. Brooks

The interlayer magnetoresistance of the quasi-two-dimensional metal $α$-(BEDT-TTF)$_2$KHg(SCN)$_4$ is considered. In the temperature range from 0.5 to 10 K and for fields up to 10 tesla the magnetoresistance has a stronger temperature dependence than the zero-field resistance. Consequently Kohler&#39;s rule is not obeyed for any range of temperatures or fiel

Yu. Berest, A. Kasman

A method of G. Wilson for generating commutative algebras of ordinary differential operators is extended to higher dimensions. Our construction, based on the theory of D-modules, leads to a new class of examples of commutative rings of partial differential operators with rational spectral varieties. As an application, we briefly discuss their link to the bis

Anjan Kundu

Basic concepts of quantum integrable systems (QIS) are presented stressing on the unifying structures underlying such diverse models. Variety of ultralocal and nonultralocal models is shown to be described by a few basic relations defining novel algebraic entries. Such properties can generate and classify integrable models systematically and also help to sol

Alexander Kogan

We give explicit formulas for the generators of $q$-deformed W-algebras associated to Lie algebras $D_n, E_6$ and $G_2$, and compute the Poisson brackets between the generators.

Frank Antonsen

We generalise the notion of coherent states to arbitrary Lie algebras by making an analogy with the GNS construction in $C^*$-algebras. The method is illustrated with examples of semisimple and non-semisimple finite dimensional Lie algebras as well as loop and Kac-Moody algebras. A deformed addition on the parameter space is also introduced simplifying some

Nark Nyul Choi, Min-Ho Lee, Sung Ho Suck Salk

A new approach to multi-dimensional quantum scattering by the infinite order discrete variable representation is presented. Determining the expansion coefficients of the wave function at the asymptotic regions by the solution of the differential Schrödinger equation, we reduce an infinite set of linear equations to a finite one. Application to the benchmark

Waldyr A. Rodrigues, Jose E. Maiorino

Representing the relativistic physical fields as sections of the Clifford Bundle (or of the Spin-Clifford Bundle) of Minkowski spacetime we show that all the relativistic wave equations satisfied by these fields possess solutions traveling with arbitrary speeds $0 \leq v < \infty$. By giving rigorous mathematical definitions of reference frames and of the Pr

D. Vretenar, S. Brant, G. Bonsignori, L. Corradini

The Interacting Boson Model with broken-pairs has been extended to include mixed proton-neutron configurations in the fermion model space. The extended version of the model has been used to describe high-spin bands in the transitional nucleus $^{136}$Nd. Model calculations reproduce ten bands of positive and negative parity states, including the two dipole h

M. Effenberger, A. Sibirtsev

Within the Glauber formalism and a BUU transport model we analyze the $η$-photoproduction data from nuclei and evaluate the in-medium $ηN$ cross section. Our results indicate that the $ηN$ cross section is almost independent of the $η$ energy up to 200 MeV.

J. Dobes, S. Pittel

Neutron-proton pairing correlations are studied within the context of two solvable models, one based on the algebra SO(5) and the other on the algebra SO(8). Boson-mapping techniques are applied to these models and shown to provide a convenient methodological tool both for solving such problems and for gaining useful insight into general features of pairing.

J. M. F. Labastida, Esther Perez

We analyse the structure of the perturbative series expansion of Chern-Simons gauge theory in the light-cone gauge. After introducing a regularization prescription that entails the consideration of framed knots, we present the general form of the vacuum expectation value of a Wilson loop. The resulting expression turns out to give the same framing dependence

Robert J. Perry

Light-front coordinates offer a scenario in which a constituent approximation of hadron structure can emerge from QCD. This requires cutoffs that violate Lorentz covariance and gauge invariance, and a new renormalization group formalism based on a similarity transformation is used with coupling coherence to fix counterterms that restore these symmetries. The

W. Beenakker, M. Krämer, T. Plehn, M. Spira

Stop particles are expected to be the lightest squarks in supersymmetric theories and the search for these particles is an important experimental task. We therefore present the cross sections for the production processes $p\bar{p}/pp \to \ste\steb$ and $\stz\stzb$ at Tevatron and LHC energies in next-to-leading order supersymmetric QCD. The corrections stabi

Yu. M. Shabelski

The diagram technique allows one to calculate the correction factors which can be used in Monte Carlo simulation of some processes. This is equivalent to the calculation with accounting for all or some part of the interference contributions. The example is presented for the simplest case of inelastic deuteron-deuteron interactions.

Dmitri Melikhov

We discuss applications of the dispersion quark model to exclusive semileptonic decays of heavy mesons. The transition form factors in this relativistic formulation of the quark model are given by double spectral representations through the wave functions of the initial and final mesons both in the scattering and the decay regions. An important feature of th

Y. Nemoto, D. Jido, M. Oka, A. Hosaka

We construct an $SU(3)_L \times SU(3)_R$ symmetric chiral effective model which includes parity pair baryon fields. It is assumed that the positive and negative parity baryons in the parity pair have opposite chiral transformation properties each other. Using this model, strong decays of the negative parity baryons are studied up to the order of one-loop cor

N. C. Tsamis, R. P. Woodard

We derive non-perturbative relations between the expectation value of the invariant element in a homogeneous and isotropic state and the quantum gravitationally induced pressure and energy density. By exploiting previously obtained bounds for the maximum possible growth of perturbative corrections to a locally de Sitter background we show that the two loop r

H. Fort

The worldsheet formulation of lattice gauge theories has two appealing features: the gauge non-redundancy and the geometrical transparency. Both properties are profitable in order to perform numerical computations. In the case of dynamical fermions this description offers additional advantages. For instance, it does not suffer from the species doubling probl

H. Arisue

The low-temperature series for the surface width of the Absolute value Solid-On-Solid model and the Discrete Gaussian model both on the square lattice and on the triangular lattice are generated to high orders using the improved finite-lattice method. The series are analyzed to give the critical points of the roughening phase transition for each model.

ZEUS Collaboration

A global event shape analysis of the multihadronic final states observed in neutral current deep inelastic scattering events with a large rapidity gap with respect to the proton direction is presented. The analysis is performed in the range $5 \leq Q^2 \leq 185\gev^2$ and $160 \leq W \leq 250\gev$, where $Q^2$ is the virtuality of the photon and $W$ is the v

The ALEPH Collaboration

A new measurement of the mean lifetime of the tau lepton is presented. Three different analysis methods are applied to a sample of 90000 tau pairs, collected in 1993 and 1994 with the ALEPH detector at LEP. The average of this measurement and those previously published by ALEPH is tau_tau = 290.1 +- 1.5 +- 1.1 fs.

Jochen Patt

The production of charged hadrons and jets is measured in collisions of quasi-real photons. The data were taken with the OPAL detector at LEP at e+e- centre-of-mass energies of 161 and 172 GeV. The measured cross-sections are compared to perturbative next-to-leading order QCD calculations. The separation of the direct and the resolved component of the photon

WA89 Collaboration, M. I. Adamovich

We report the first observation of the Xi- pi+ decay mode of the Xi0(1690), confirming the existence of this resonance. The Xi0(1690) were produced by Sigma- of 345 Gev/c mean momentum in copper and carbon targets. The mass and width are close to those observed earlier for the Xi-(1690) in the Lambda K- decay channel. The product of inclusive production cros

M. Bishai

Using data recorded by the CLEO II detector at CESR, we have searched for the decay B -> Ds1+(2536) X, where Ds1+ is the narrow P-wave D_s^+ meson with J^P=1^+. The upper limit to the inclusive branching fraction is measured to be Br(B -> Ds1+ X) < 0.95% at the 90% confidence level. This limit is small compared with the total expected B -> Dbar(*)D(*)KX rate

A. Sopczak

The discovery potential for charged Higgs bosons has been studied including background simulations for sqrts = 500 GeV and a luminosity of 10 fb-1 depending on the hadronic calorimeter resolution of a LC500 detector. The hadronic decay channel H+H- --> cscs is in particular suited for this study due to a large sensitivity dependence on the hadron calorimeter

N. H. Brook

This lecture contains a brief introduction to CP violation in the B system before discussing future experimental programmes and their CP reach in the B system.

N. H. Brook

This lecture contains a brief introduction to HERA and deep inelastic scattering (DIS), before going on to highlight some of the measurements of the hadronic final state in DIS performed by the H1 and ZEUS collaborations.

Dario Nunez

A model for a possible variable cosmic object is presented. The model consists of a massive shell surrounding a compact object. The gravitational and self-gravitational forces tend to collapse the shell, but the internal tangential stresses oppose the collapse. The combined action of the two types of forces is studied and several cases are presented. In part

Gerard Clement

The Kerr solution is generated from the Schwarzschild solution by a simple combination of real global coordinate transformations and of invariance transformations acting on the space of stationary solutions of the Einstein-Maxwell equations. The same transformation can be used to generate a spinning field configuration from any static axisymmetric configurat

Alejandro Rivero

We present some plausible definitions for the tangent grupoid of a manifold M, as well as some of the known applications of the structure. This is a kind of introductory note.

Jonathan Woolf

Paper withdrawn - lemma 4.1 was false. Quite a lot of changes need to be made!

Alexandre M Zagoskin, Masaki Oshikawa

We consider spontaneous magnetic flux in a doubly connected s-wave/normal metal/ d-wave superconductor (SND) Josephson junction. The flux magnitude is not quantized and is determined by the parameters of the system. In an isolated system, quantum fluctuations of the superconducting phase take place, leading to quantum flux noise. The possibilities of experim

Dirk. K. Morr, Joerg Schmalian, Raivo Stern, Charles P. Slichter

In a recent letter (PRL 79, 2117 (1997)), Bobroff et al. presented novel $^{17}$O NMR measurements for YBa_2(Cu_{1-x}Ni_x)_3O_{6+y} which offer a new probe of the momentum dependence of the static spin susceptibility $χ&#39;(q)$. They analyzed the $^{17}$O line width by assuming a Gaussian form for $χ&#39;$, and came to the conclusion that the correlation le

Zlatko Tesanovic, Pedro D. Sacramento

At high magnetic fields and low temperatures, numerous extreme type-II superconductors exhibit Landau quantization of electronic motion. We present an analytic construction of the quasiparticle spectrum in this regime, based on the high-field expansion. The spectrum is gapless and is separated from the familiar low-field regime by a quantum level-crossing tr

J. Ashkenazi

Non-Fermi-liquid features of the high-Tc cuprates, and specifically the systematic behavior of the resistivity, Hall constant, and thermoelectric power, are shown to result from an electronic structure based on &#34;large-U&#34; and &#34;small-U&#34; orbitals, and the resulting striped structure.

L. Leylekian, M. Ocio, L. A. Gurevich, M. V. Feigel&#39;man

The properties of the low excitation field magnetic response of the granular high temperature (HTSC) superconductor LaSrCuO have been analyzed at low temperatures. The response of the Josephson currents has been extracted from the data. It is shown that intergrain current response is fully irreversible, producing shielding response, but do not carry Meissner

L. Frachebourg, P. L. Krapivsky, S. Redner

The kinetics of annihilating random walks in one dimension, with the half-line x>0 initially filled, is investigated. The survival probability of the nth particle from the interface exhibits power-law decay, S_n(t)~t^{-alpha_n}, with alpha_n approximately equal to 0.225 for n=1 and all odd values of n; for all n even, a faster decay with alpha_n approximatel

Alok Shukla, Michael Dolg, Peter Fulde, Hermann Stoll

An ab initio Hartree-Fock approach aimed at directly obtaining the localized orthogonal orbitals (Wannier functions) of a crystalline insulator is described in detail. The method is used to perform all-electron calculations on the ground states of crystalline lithium fluoride and lithium chloride, without the use of any pseudo or model potentials. Quantities

I. V. Ostrovskii, S. V. Saiko, O. Ya. Olikh, H. G. Walther

A new acousto-electrical method making use of transient transverse acoustoelectric voltage (TAV) to study solid state structures is reported. This voltage arises after a surface acoustic wave (SAW) generating the signal is switched off. Related measurements consist in detecting the shape of transient voltage and its spectral and temperature dependence. Both

Ulrich H. E. Hansmann, Philippe de Forcrand

We describe a simple ansatz to approximate the low temperature behavior of proteins and peptides by a mean-field-like model which is analytically solvable. For a small peptide some thermodynamic quantities are calculated and compared with numerical results of an all-atoms simulation. Our approach can be used to determine the weights for a multicanonical simu

Imre Varga, Janos Pipek

The scale invariant properties of wave functions in finite samples of one dimensional random systems with correlated disorder are analyzed. The random dimer model and its generalizations are considered and the wave functions are compared. Generalized entropic localization lengths are introduced in order to characterize the states and compared with their beha

Nikolai Prokof&#39;ev, Philip Stamp

We argue that to explain recent resonant tunneling experiments on crystals of Mn$_{12}$ and Fe$_8$, particularly in the low-T limit, one must invoke dynamic nuclear spin and dipolar interactions. We show the low-$T$, short-time relaxation will then have a $\sqrt{t/τ}$ form, where $τ$ depends on the nuclear $T_2$, on the tunneling matrix element $Δ_{10}$ betw

Giovanni Gallavotti

Local integrability of hyperbolic oscillators is discussed to provide an introductory example of the Arnold&#39;s diffusion phenomenon in a forced pendulum. This is a text prepared for the the ISI summer school of June 1997 and deals with developments of the topics treated in the lectures.

G. A. Bower, R. F. Green

We present optical long-slit spectroscopy of the nucleus of the nearby radio galaxy M84 (NGC 4374 = 3C 272.1) obtained with the Space Telescope Imaging Spectrograph (STIS) aboard the Hubble Space Telescope (HST). Our spectra reveal that the nuclear gas disk seen in WFPC2 imaging by Bower et al. (1997, ApJ, 483, L33) is rotating rapidly. The velocity curve ha

S. L. W. McMillan, C. Pryor, E. S. Phinney

Binary stars play a critical role in determining both the dynamical evolution and the observational appearance of globular star clusters. We present a summary of three talks presented at IAU JD15, reviewing the current observational and theoretical status of binaries and related ``exotic&#39;&#39; stars in the Galactic globular cluster system.

A. Barrau, R. Bazer-Bachi, H. Cabot, L. M. Chounet

The CAT imaging telesope, which uses the Atmospheric Cherenkov Technique to observe TeV gamma-ray sources, has been operating since September 1996. Located in southern France, it features a fine grained camera consisting of 546 PMT with a pixel size of 0.12 degrees. Strong gamma-ray signals from Mkn 501 above 200 GeV were detected during observations made in

A. Barrau, R. Bazer-Bachi, H. Cabot, L. M. Chounet

The CAT Imaging Telescope has observed the BL Lac object Markarian 501 between March and August 1997. We report here on the variability over this time including several large flares. We present also preliminary spectra for all these data, for the low emission state, and for the largest flare.

Alec Boksenberg

An extremely careful analysis of the forest of weak metal-line systems at z ~ 2 has allowed the separation into individual `single-phase ionization&#39; components with accurate parameters. The systems typically span several hundred km/s and within each the components show a strong coherence in their ionization properties. A general feature of the observed s

V. Castellani, A. Di Paolantonio, A. M. Piersimoni, V. Ripepi

We present CCD lightcurves for the three field RR Lyrae AQ Lyr, CN Lyr and AW Dra observed at the Teramo TNT telescope. Stellar temperatures have been derived from the observed mean colors, allowing a comparison with recent theoretical predictions on RR Lyrae lightcurves. As for the two metal rich pulsators in the sample we suggest that CN Lyr has been possi

Garrelt Mellema, Adam Frank

In this paper we explore the effect of radiative losses on purely hydrodynamic jet collimation models applicable to Young Stellar Objects (YSOs). In our models aspherical bubbles form from the interaction of a central YSO wind with an aspherical circum-protostellar density distribution. Building on a previous non-radiative study (Frank & Mellema 1996) we dem

C. Henkel, Y. -N. Chin, R. Mauersberger, J. B. Whiteoak

$^{12}$C$/^{13}$C line intensity ratios have been derived from several carbon-bearing molecules to confine the range of carbon and oxygen isotope abundance ratios toward the nuclear regions of two infrared bright galaxies. The most stringent limits are obtained from CN mm-wave emission lines. Supplementary measurements toward the Galactic center region indic

Y. -N. Chin, C. Henkel, T. J. Millar, J. B. Whiteoak

Detections of CO, CS, SO, C2H, HCO+, HCN, HNC, H2CO, and C3H2 reported from LIRS 36, a star-forming region in the Small Magellanic Cloud. C18O, NO, CH3OH, and most notably CN have not been detected, while the rare isotopes 13CO and, tentatively, C34S are seen. This is so far the most extensive molecular multiline study of an interstellar medium with a heavy

Daniel J. Eisenstein, Wayne Hu

The bulk of recent cosmological research has focused on the adiabatic cold dark matter model and its simple extensions. Here we present an accurate fitting formula that describes the matter transfer functions of all common variants, including mixed dark matter models. The result is a function of wavenumber, time, and six cosmological parameters: the massive

D. Kaledin

Let $M$ be a Kaehler manifold, and consider the total space $T^*M$ of the cotangent bundle to $M$. We show that in the formal neighborhood of the zero section $M \subset T^*M$ the space $T^*M$ admits a canonical hyperkaehler structure, compatible with the complex and holomorphic symplectic structures on $T^*M$. The associated hyperkaehler metric $h$ coincide

M. Dine, A. Rajaraman

We consider scattering processes in the matrix model with three incoming and three outgoing gravitons. We find a discrepancy between the amplitude calculated from the matrix model and the supergravity prediction. Possible sources for this discrepancy are discussed.

S. W. Sides, P. A. Rikvold, M. A. Novotny

Experiments on ferromagnetic thin films have measured the dependence of the hysteresis loop area on the amplitude and frequency of the external field, $A$=$A(H_{0},ω)$, and approximate agreement with numerical simulations of Ising models has been reported. Here we present numerical and theoretical calculations of $A$ in the low-frequency regime for two value

Thomas J. Weiler

If neutrinos are a significant contributor to the matter density of the universe, then they should have $\sim$ eV mass and cluster in galactic (super) cluster halos, and possibly in galactic halos as well. It was noted in the early 1980&#39;s that cosmic ray neutrinos with energy within $δE/E_R=Γ_Z/M_Z \sim 3%$ of the peak energy $E_R=4 (eV/m_ν)\times 10^{21

Guy D. Moore, Chaoran Hu, Berndt Muller

We construct an extension of the standard Kogut-Susskind lattice model for classical 3+1 dimensional Yang-Mills theory, in which ``classical particle&#39;&#39; degrees of freedom are added. We argue that this will correctly reproduce the ``hard thermal loop&#39;&#39; effects of hard degrees of freedom, while giving a local implementation which is numerically

A. A. Bytsenko, L. Vanzo, S. Zerbini

The thermodynamic properties of the (2+1)-dimensional non-rotating black hole of Bañados, Teitelboim and Zanelli are discussed. The first quantum correction to the Bekenstein-Hawking entropy is evaluated within the on-shell Euclidean formalism, making use of the related Chern-Simons representation of the 3-dimensional gravity. Horizon and ultraviolet diverge

Emilio Elizalde, Antonio Filippi, Luciano Vanzo, Sergio Zerbini

The one-loop partition function for a charged self-interacting Bose gas at finite temperature in D-dimensional spacetime is evaluated within a path integral approach making use of zeta-function regularization. For D even, a new additional vacuum term ---overlooked in all previous treatments and coming from the multiplicative anomaly related to functional det

ZEUS Collaboration

Dijet cross sections are presented using photoproduction data obtained with the ZEUS detector during 1994. These measurements represent an extension of previous results, as the higher statistics allow cross sections to be measured at higher jet transverse energy (ETJ). Jets are identified in the hadronic final state using three different algorithms, and the

T. M. Aliev, C. S. Kim

We propose a new method for precise determination of |V_{td} / V_{ub}| from the ratios of branching ratios BR(B -> ρν\bar ν) / BR(B ->ρl ν) and BR(B -> πν\bar ν) / BR(B -> πl ν). These ratios depend only on the ratio of the Cabibbo-Kobayashi-Maskawa (CKM) elements |V_{td} / V_{ub}|$ with little theoretical uncertainty, when very small isospin breaking effect

J. Harnad

A comparison is made between bispectral systems and dual isomonodromic deformation equations. A number of examples are given, showing how bispectral systems may be embedded into isomonodromic ones. Sufficiency conditions are given for the construction of rational solutions of isomonodromic deformation equations through the Riemann-Hilbert problem dressing me

Anupam Garg

The ion trap quantum computer proposed by Cirac and Zoller is analyzed for decoherence due to vibrations of the ions. An adiabatic approximation exploiting the vast difference between the frequencies of the optical intraionic transition and the vibrational modes is used to find the decoherence time at any temperature T. The scaling of this decoherence time w

Karl Svozil

Two aspects of the physical side of the Church-Turing thesis are discussed. The first issue is a variant of the Eleatic argument against motion, dealing with Zeno squeezed time cycles of computers. The second argument reviews the issue of one-to-one computation, that is, the bijective (unique and reversible) evolution of computations and its relation to the

P. Bouwknegt, K. Pilch

We discuss some aspects of the representation theory of the deformed Virasoro algebra $\virpq$. In particular, we give a proof of the formula for the Kac determinant and then determine the center of $\virpq$ for $q$ a primitive N-th root of unity. We derive explicit expressions for the generators of the center in the limit $t=qp^{-1}\to \infty$ and elucidate

M. I. Molina

Two simple, interpolatory-like linearizations are shown for the simple pendulum which can be used for any initial amplitude.

P. Ring, Y. K. Gambhir, G. A. Lalazissis

A Fortran program for the calculation of the ground state properties of axially deformed even-even nuclei in the relativistic framework is presented. In this relativistic mean field (RMF) approach a set of coupled differential equations namely the Dirac equation with potential terms for the nucleons and the Glein-Gordon type equations with sources for the me

D. Anchishkin, U. Heinz, P. Renk

We reconsider the influence of two-particle final state interactions (FSI) on two-particle Bose-Einstein interferometry. We concentrate in particular on the problem of particle emission at different times. Assuming chaoticity of the source, we derive a new general expression for the symmetrized two-particle cross section. We discuss the approximations needed

Giampaolo Co&#39;, Antonio M. Lallena

The contribution of the two-nucleon emission in the longitudinal response for inclusive electron scattering reactions is studied. The model adopted to perform the calculations is based upon Correlated Basis Function theory but it considers only first order terms in the correlation function. The proper normalization of the wave function is ensured by consider

M. P. Blencowe, H. F. Jones, A. P. Korte

The linear $δ$ expansion (LDE) is applied to the Hamiltonian $H=(p^2 +m^2 x^2)/2 + igx^3$, which arises in the study of Lee-Yang zeros in statistical mechanics. Despite being non-Hermitian, this Hamiltonian appears to possess a real, positive spectrum. In the LDE, as in perturbation theory, the eigenvalues are naturally real, so a proof of this property devo

C. D. Fosco

Recently derived results for the exact induced parity-breaking term in 2+1 dimensions at finite temperature are shown to be relevant to the determination of the free energy for fixed-charge ensembles. The partition functions for fixed total charge corresponding to massive fermions in the presence of Abelian and non-Abelian magnetic fields are discussed. We s

O. Eboli, F. Halzen, K. Mizukoshi

The sources of $W + n$-jet events in hadron collisions are higher-order QCD processes, but also multiple-parton interactions. A subprocess producing a $W + k$-jet final state, followed by one producing $l$ jets in the same nucleon-nucleon interaction, will result in a $W + n$-jet event if $k + l = n$. In the simplest case a $W + 2$-jet event can be produced

F. del Aguila, M. Perez-Victoria

We review the method of differential renormalization, paying special attention to a new constrained version for symmetric theories.

K. S. Babu, Christopher Kolda, John March-Russell

We discuss experimental implications of extending the gauge structure of the Standard Model to include an additional U(1) interaction broken at or near the weak scale. We work with the most general, renormalizable Lagrangian for the SU(2)\times U(1)\times U(1) sector, with emphasis on the phenomenon of gauge kinetic mixing between the two U(1) gauge fields,