May 1996 arXiv papers — page 13

Klaus Lucke

We describe an approach to classify (meromorphic) representations of a given vertex operator algebra by calculating Zhu's algebra explicitly. We demonstrate this for FKS lattice theories and subtheories corresponding to the Z_2 reflection twist and the Z_3 twist. Our work is mainly offering a novel uniqueness tool, but, as shown in the Z_3 case, it can a

Stefano De Leo, Pietro Rotelli

We explicitly develop a quaternionic version of the electroweak theory, based on the local gauge group $U(1, q)_{L}\mid U(1, c)_{Y}$. The need of a complex projection for our Lagrangian and the physical significance of the anomalous scalar solutions are also discussed.

Tomomi Muto

Thermodynamic properties of a class of black $p$-branes in $D$-dimensions considered by Duff and Lu are investigated semi-classically. For black $(d-1)$-brane, thermodynamic quantities depend on $D$ and $d$ only through the combination $\tilde d \equiv D-d-2$. The behavior of the Hawking temperature and the lifetime vary with $\tilde d$, with a critical valu

Juan M. Maldacena

The Hawking Beckenstein entropy of near extremal fivebranes is calculated in terms of a gas of strings living on the fivebrane. These fivebranes can also be viewed as near extremal black holes in five dimensions.

Riccardo Barbieri, Lawrence Hall

A grand unified $SU(5)$ theory is constructed with a hierarchical breaking of a $U(2)$ flavor symmetry. The small parameters of the squark and slepton mass matrices, necessary to solve the supersymmetric flavor-changing problem, and the inter-generational quark and lepton mass hierarchies are both generated from the $U(2)$ symmetry breaking parameters. The f

J. Randrup

Considering a variety of dynamical scenarios within the linear sigma model, we examine the conditions for pionic modes to be amplified as the chiral field relaxes towards the normal vacuum following the transient restoration of approximate chiral symmetry in a high-energy collision. While Bjorken-type longitudinal expansions appear to be insufficient for amp

Stefano Borgani, Antonio Masiero, Masahiro Yamaguchi

In theories with a gauge-mediated mechanism of supersymmetry breaking the gravitino is likely to be the lightest superparticle and, hence, a candidate for dark matter. We show that the decay of the next-to-lightest superparticle into a gravitino can yield a non-thermal population of gravitinos which behave as a hot dark matter component. Together with the wa

Robert Fleischer, Isard Dunietz

We demonstrate that time-dependent studies of angular distributions for $B_s$ decays caused by $\bar b\to\bar cu\bar s$ quark-level transitions extract cleanly and model-independently the CKM angle $γ$. This CKM angle could be cleanly determined from untagged $B_s$ decays alone, if the lifetime difference between the $B_s$ mass eigenstates $B_s^L$ and $B_s^H

Robert Fleischer, Isard Dunietz

We investigate the time-evolutions of angular distributions for $B_s$ decays into final states that are admixtures of CP-even and CP-odd configurations. A sizable lifetime difference between the $B_s$ mass eigenstates allows a probe of CP violation in time-dependent untagged angular distributions. Interference effects between different final state configurat

P. Chiappetta, C. Verzegnassi, A. Fiandrino, J. Layssac

The limits on extra neutral gauge bosons, which could be reached at LEP2, are reviewed. Exclusion and discovery limits are discussed for f\bar f and WW production.

R. A. Alanakyan

In the framework of the models with Higgs triplets, double charged Higgs bosons production in the processes $e^-e^-\toδ^{--}_{L,R}γ$ are considered.

A. Capella

Due to the long-standing discrepancy between NA35 and NA36 data on $Λ$ production, two drastically different scenarios of strangeness enhancement are still possible. Independent string models, such as the dual parton model, lead to results close to the NA36 data. On the contrary, the NA35 results can only be described by introducing full final state rescatte

Xin-Nian Wang, Zheng Huang, Ina Sarcevic

We point out that events associated with large $E_T$ direct photons in high-energy heavy-ion collisions can be used to study jet energy loss in dense matter. In such events, the $p_T$ spectrum of charged hadrons from jet fragmentation in the opposite direction of the tagged photon is estimated to be well above the background which can be reliably subtracted

A. Papa

The free energy density of the SU(3) gauge theory at temperatures T/T_c = 4/3, 3/2 and 2 is calculated on lattices with temporal extent as small as N_t = 2, 3 and spatial extent N_s = 4 N_t using parametrized fixed point actions. Although cut-off effects are seen, they are hugely suppressed with respect to Wilson and Symanzik-improved actions and at N_t = 3

She-Sheng Xue

Analyzing an $SU_L(2)\otimes U_R(1)$ chiral theory with multifermion couplings on a lattice, we find a possible region in the phase space of multifermion couplings, where no spontaneous symmetry breaking occurs, doublers are decoupled as massive Dirac fermions consistently with the $SU_L(2)\otimes U_R(1)$ chiral symmetry, the ``spectator'' fermion $ψ

H. P. de Oliveira

We use the technique of conformal transformations to generate self-similar collapse in Brans-Dicke theory. We analyze the solutions concerning the critical behavior found recently by Choptuik. The critical exponent associated to the formation of black hole for near critical evolution is obtained. The role of the coupling parameter is discussed.

R. Melin, B. Doucot, CRTBT, Grenoble

We consider a RG approach for the plasma of magnetic monopoles of the Ioffe-Larkin approach to the t-J model. We first derive the interaction parameters of the 2+1 plasma of magnetic monopoles. The total charge along the time axis is constrained to be zero for each lattice plaquette. Under the one-plaquette approximation, the problem is equivalent to a one d

J. M. P. Carmelo, A. H. Castro Neto

We show that in the presence of a magnetic field the usual low-energy separation of the Hubbard chain is replaced by a ``$c$'' and ``$s$'' separation. Here $c$ and $s$ refer to small-momentum and low-energy independent excitation modes which couple both to charge and spin. Importantly, we find the exact generators of these excitations both in

J. C. Cuevas, A. Martin-Rodero, A. Levy Yeyati

A microscopic theory of the transport properties of quantum point contacts giving a unified description of the normal conductor- superconductor (N-S) and superconductor-superconductor (S-S) cases is presented. It is based on a model Hamiltonian describing charge transfer processes in the contact region and makes use of non-equilibrium Green function techniqu

G. Caldarelli, C. Tebaldi, A. L. Stella

In a critically self--organized model of punctuated equilibrium, boundaries determine peculiar scaling of the size distribution of evolutionary avalanches. This is derived by an inhomogeneous generalization of standard branching processes, extending previous mean field descriptions and yielding $ν=1/2$ together with $τ'=7/4$, as distribution exponent of

D. H. Cobden, B. A. Muzykantskii

We show that random telegraph signals in metal-oxide-silicon transistors at millikelvin temperatures provide a powerful means of investigating tunneling between a two-dimensional electron gas and a single defect state. The tunneling rate shows a peak when the defect level lines up with the Fermi energy, in excellent agreement with theory of the Fermi-edge si

M. Hasenbusch, K. Pinn

We study the roughening transition of the dual of the 2D XY model, of the Discrete Gaussian model, of the Absolute Value Solid-On-Solid model and of the interface in an Ising model on a 3D simple cubic lattice. The investigation relies on a renormalization group finite size scaling method that was proposed and successfully tested a few years ago. The basic i

Heiko Leschhorn

We study numerically a stochastic differential equation describing an interface driven along the hard direction of an anisotropic random medium. The interface is subject to a homogeneous driving force, random pinning forces and the surface tension. In addition, a nonlinear term due to the anisotropy of the medium is included. The critical exponents character

Y. Galperin, O. Entin-Wohlman

The magnetic response of strongly localized electrons to a time-dependent vector potential is considered. The orbital magnetic moment of the system, away from steady-state conditions, is obtained. The expression involves the tunneling and phonon-assisted hopping currents between localized states. The frequency and temperature dependence of the orbital magnet

Philippe Blache, Jean-Louis Paquelin

In this paper, we characterize the properties of a direct interpretation of HPSG and present the advantages of this approach. High-level programming languages constitute in this perspective an efficient solution: we show how a multi-paradigm approach, containing in particular constraint logic programming, offers mechanims close to that of the theory and pres

Dean E. McLaughlin, Ralph E. Pudritz

We generalize the classic Bonnor-Ebert stability analysis of pressure-truncated, self-gravitating gas spheres, to include clouds with arbitrary equations of state. A virial-theorem analysis is also used to incorporate mean magnetic fields into such structures. The results are applied to giant molecular clouds (GMCs), and to individual dense cores, with an ey

W. E. Ballinger, J. A. Peacock, A. F. Heavens

It has been proposed that the cosmological constant $Λ$ might be measured from geometric effects on large-scale structure. A positive vacuum density leads to correlation-function contours which are squashed in the radial direction when calculated assuming a matter-dominated model. We show that this effect will be somewhat harder to detect than previous calcu

Prasenjit Saha, Joachim Stadel, Scott Tremaine

We describe how long-term solar system orbit integration could be implemented on a parallel computer. The interesting feature of our algorithm is that each processor is assigned not to a planet or a pair of planets but to a time-interval. Thus, the 1st week, 2nd week,..., 1000th week of an orbit are computed concurrently. The problem of matching the input to

Sandip K. Chakrabarti

We describe astrophysical processes around a black hole keeping primarily the physics of accretion in mind. In Section 1, we briefly discuss the formation, evolution and detection of black holes. We also discuss the difference of flow properties around a black hole and a Newtonian star. In Section 2, we present past and present developments in the study of s

Victor A. Gopar, Pier A. Mello, Markus Buttiker

The capacitance of mesoscopic samples depends on their geometry and physical properties, described in terms of characteristic times scales. The resulting ac admittance shows sample to sample fluctuations. Their distribution is studied here -through a random-matrix model- for a chaotic cavity capacitively coupled to a backgate: it is observed from the distrib

David B. Kaplan, Martin J. Savage, Mark B. Wise

We perform a nonperturbative calculation of the 1S0 NN scattering amplitude using an effective field theory (EFT) expansion. The expansion we advocate is a modification of what has been used previously; it is no a chiral expansion in powers of the pion mass. We use dimensional regularization throughout and the MS-bar subtraction scheme; our final result depe

Edmond L. Berger, Harry Contopanagos

Our calculation of the total cross section for inclusive production of $t\bar{t}$ pairs in hadron collisions is summarized. The principal ingredient of this calculation is resummation of the universal leading-logarithm effects of gluon radiation to all orders in the quantum chromodynamics coupling strength, restricted to the region of phase space that is man

M. Dorca, E. Verdaguer

Following a previous work on the quantization of a massless scalar field in a spacetime representing the head on collision of two plane waves which fucus into a Killing-Cauchy horizon, we compute the renormalized expectation value of the stress-energy tensor of the quantum field near that horizon in the physical state which corresponds to the Minkowski vacuu

Manoelito M. de Souza

We present a pedagogical review of old inconsistencies of Classical Electrodynamics and of some new ideas that solve them. Problems with the electron equation of motion and with the non-integrable singularity of its self-field energy tensor are well known. They are consequences, we show, of neglecting terms that are null off the charge world-line but that gi

E. Kiritsis, C. Kounnas, M. Petropoulos, J. Rizos

We present in detail the procedure for calculating the heterotic one-loop effective action. We focus on gravitational and gauge couplings. We show that the two-derivative couplings of the gravitational sector are not renormalized at one loop when the ground state is supersymmetric. Arguments are presented that this non-renormalization theorem persists to all

L. Chekhov, C. Kristjansen

We study a hermitian $(n+1)$-matrix model with plaquette interaction, $\sum_{i=1}^n MA_iMA_i$. By means of a conformal transformation we rewrite the model as an $O(n)$ model on a random lattice with a non polynomial potential. This allows us to solve the model exactly. We investigate the critical properties of the plaquette model and find that for $n\in]-2,2

Inès Safi, H. J. Schulz

Transport through a one-dimensional wire of interacting electrons connected to semi infinite leads is investigated using a bosonization approach. The dynamic nonlocal conductivity is rigorously expressed in terms of the transmission. For abrupt variations of the interaction parameters at the junctions, an incident electron is transmitted as a sequence of par

N. D. Lambert

We explicitly construct massive (0,4) supersymmetric ADHM sigma models which have heterotic p-brane solitons as their conformal fixed points. These yield the familiar gauge 5-brane and a new 1-brane solution which preserve 1/2 and 1/4 of the spacetime supersymmetry respectively. We also discuss an analogous construction for the type II NS-NS p-branes using (

A. T. Filippov

A class of integrable models of 1+1 dimensional dilaton gravity coupled to scalar and electromagnetic fields is obtained and explicitly solved. More general models are reduced to 0+1 dimensional Hamiltonian systems, for which two integrable classes (called s-integrable) are found and explicitly solved. As a special case, static spherical solutions of the Ein

K. S. Viswanathan, R. Parthasarathy

Intrinsic and extrinsic geometric properties of string world sheets in curved space-time background are explored. In our formulation, the only dynamical degrees of freedom of the string are its immersion coordinates. Classical equation of motion and the space-time energy-momentum tensor of the string are obtained. The equations of motion for the extrinsic cu

C. S. Kim

In order to determine the ratio of CKM matrix elements |V_{ub}/V_{cb}| (and |V_{ub}|), we propose a new model-independent method based on the heavy quark effective theory, which is theoretically described by the phase space factor and the well-known perturbative QCD correction only. In the forthcoming asymmetric B-experiments with microvertex detectors, BABA

Kimio Ueno, Michitomo Nishizawa

We give an asymptotic expansion (the higher Stirling formula) and an infinite product representation (the Weierstrass product representation) of the Vignéras multiple gamma functions by considering the classical limit of the multiple q-gamma functions.

R. Prozorov, A. Poddar, E. Sheriff, A. Shaulov

The magnetization M of a thin YBaCuO film is measured as a function of the angle $θ$ between the applied field H and the c-axis. For fields above the first critical field, but below the Bean's field for first penetration H*, M is symmetric with respect to $θ=π$ and the magnetization curves for forward and backward rotation coincide. For H>H* the curves a

I. Antoniou, B. Pavlov, A. Yafyasov

Two types of optically manipulated quantum electronic devices are considered: a quantum dot and a finite periodic molecular chain, with the period doubled under resonance optical excitation. The stability of the working regimes of the devices in large scale of temperatures is discussed. Some motivation in favor of the molecular chain is suggested. A class of

Arkady Vaintrob

We study the asymptotic expansion of the colored Jones polynomial (the Melvin-Morton expansion) using a recursion formula for the deframed universal weight system for the $sl(2)$ Lie algebra. Combined with the formula for the universal weight system for the Lie superalgebra $gl(1|1)$ (which corresponds to the Alexander-Conway knot polynomial) this formula gi

Apostolos A. Giannopoulos, Vitali D. Milman

Let $K$ be a symmetric convex body in ${\mathbf R}^n$. It is well-known that for every $θ\in (0,1)$ there exists a subspace $F$ of ${\mathbf R}^n$ with ${\rm dim}F= [(1-θ)n]$ such that $${\mathcal P}_F(K)\supseteq \frac{c\sqrt{θ}} {M_K}D_n\cap F,\leqno (\ast )$$ where ${\mathcal P}_F$ denotes the orthogonal projection onto $F$. Consider a fixed coordinate sy

Antonis Tsolomitis

We introduce the mixed convolution bodies of two convex symmetric bodies. We prove that if the boundary of a body $K$ is smooth enough then as $δ$ tends to $1$ the $δ$--$M^*$--convolution body of $K$ with itself tends to a multiple of the Euclidean ball after proper normalization. On the other hand we show that the $δ$--$M^*$--convolution body of the $n$--di

T. Y. Lam, K. H. Leung

In an earlier work, the authors have determined all possible weights $n$ for which there exists a vanishing sum $ζ_1+\cdots +ζ_n=0$ of $m$th roots of unity $ζ_i$ in characteristic 0. In this paper, the same problem is studied in finite fields of characteristic $p$. For given $m$ and $p$, results are obtained on integers $n_0$ such that all integers $n\geq n_

James Ball, Wei Chen

We examine a criterion for the anyonic superconductivity at zero temperature in Abelian matter-coupled Chern-Simons gauge field theories in three dimensions. By solving the Dyson-Schwinger equations, we obtain a critical value of the statistical charge for the superconducting phase in a massless fermion-Chern-Simons model.

M. Petropoulos

In the framework of a recently proposed method for computing exactly string amplitudes regularized in the infra-red, I determine the one-loop correlators for auxiliary fields in the symmetric $Z_2\times Z_2$ orbifold model. The $D$-field correlation function turns out to give the one-loop corrections for the gauge couplings, which amounts to a string-theory

Ursula Carow-Watamura, Satoshi Watamura

We give a derivation of the Dirac operator on the noncommutative $2$-sphere within the framework of the bosonic fuzzy sphere and define Connes' triple. It turns out that there are two different types of spectra of the Dirac operator and correspondingly there are two classes of quantized algebras. As a result we obtain a new restriction on the Planck cons

Valentin E. Kuznetsov, Vadim A. Naumov

We discuss the formulas for one-to-one correspondence between the two popular parametrizations of the quark mixing matrix and the confidence limits for the mixing parameters.

M. Klasen, G. Kramer

We have calculated the single jet inclusive cross section as measured at Fermilab in next-to-leading order QCD using recent parton distributions of the CTEQ collaboration. We studied the scheme dependence of the jet cross section by employing the $\overline{\mbox{MS}}$ and DIS factorization schemes consistently. For $E_T > 200$ GeV, we find that the cross se

S. Frixione, G. Ridolfi

We consider the possibility of a direct determination of the polarized gluon density in the proton using charm production with polarized beams at HERA. We study total cross sections and distributions at leading order using different parametrizations of the polarized gluon density. We conclude that charm photoproduction data can be used to constrain the polar

J. Nemchik, N. N. Nikolaev, E. Predazzi, B. G. Zakharov

We present the color dipole phenomenology of diffractive photo- and electroproduction $γ^{*} N\to V(V') N$ of vector mesons ($V(1S) = ϕ^0, ω^0, ρ^0, J/Ψ, Υ$) and their radial excitations ($V'(2S) = ϕ', ω', ρ', Ψ', Υ'$). The main emphasis is related to light vector mesons. We discuss how the energy dependence of the color dipole cr

A. V. Kotikov, G. Parente

We present a set of formulae to extract the longitudinal deep inelastic structure function $F_L$ from the transverse structure function $F_2$ and its derivative $dF_2/dlnQ^2$ at small $x$. Our expressions are valid for any value of $δ$, being $x^{-δ}$ the behavior of the parton densities at low $x$. Using $F_2$ HERA data we obtain $F_L$ in the range $10^{-4}

V. Morénas, A. Le Yaouanc, L. Oliver, O. Pène

Once chosen the dynamics in one frame, for example the rest frame, the Bakamjian and Thomas method allows to define relativistic quark models in any frame. These models have been shown to provide, in the heavy quark limit, fully covariant current form factors as matrix elements of the quark current operator. They also verify the Isgur-Wise scaling and give a

M. Chaichian, M. Hayashi

We work out the method for evaluating the QCD coupling constant at finite temperature ($T$) by making use of the finite $T$ renormalization group equation up to the one-loop order on the basis of the background field method with the imaginary time formalism. The background field method, which maintains the explicit gauge invariance, provides notorious simpli

George Wei-Shu Hou

We study the possibility of discovering resonances in $μ^+e^- \to μ^- e^+$ and $e^-e^- \to μ^- μ^-$ collisions. We begin with the closely related problem of muonium--antimuonium transitions, where the experimental limit has just been improved by one order of magnitude. We show that the new limit enters a rather interesting mass and Yukawa coupling domain for

George Wei-Shu Hou

As the excitement surrounding the heavy top quark discovery subsides, while the expectation for LEP II physics gathers, it is a good time to sit back and reflect on whether energy regions available to us have been fully explored. We emphasize that a loophole exists where heavy quarks, perhaps the actual top quark itself, could still be hidden below $M_W$. Th

G. M. de Divitiis, R. Frezzotti, M. Masetti, R. Petronzio

We study the dynamical flavour dependence of the lattice estimates of the heavy meson decay constant in the static limit. We perform the analysis by considering negative flavour numbers and by extrapolating the results to positive values. We observe a sizeable flavour dependence which increases the quenched estimates.

S. Brian Edgar, Garry Ludwig

Held has proposed a coordinate- and gauge-free integration procedure within the GHP formalism built around four functionally independent zero-weighted scalars constructed from the spin coefficients and the Riemann tensor components. Unfortunately, a spacetime with Killing vectors will be unable to supply the full quota of four scalars of this type. However,

Knut Smoczyk

We introduce the notion of Fermi flow for hypersurfaces in Riemannian manifolds. It turns out that this is a powerful tool to study the geometry of distance surfaces about a given initial hypersurface. Some of the results in this paper are known in one form or another, however the aim is to demonstrate how they can all be derived by the same method and prove

Mark J. Gotay, Hendrik B. Grundling, Gijs M. Tuynman

We define the quantization structures for Poisson algebras necessary to generalise Groenewold and Van Hove's result that there is no consistent quantization for the Poisson algebra of Euclidean phase space. Recently a similar obstruction was obtained for the sphere, though surprising enough there is no obstruction to the quantization of the torus. In thi

Michael Pascaud, Gilles Montambaux

We study the magnetic response of mesoscopic metallic isolated networks. We calculate the average and typical magnetizations in the diffusive regime for non-interacting electrons or in the first order Hartree-Fock approximation. These quantities are related to the return probability for a diffusive particle on the corresponding network. By solution of the di

Ned S. Wingreen, Charles A. Stafford

We propose a quantum-dot version of the quantum-well cascade laser of Faist et al. [Science {\bf 264}, 553 (1994)]. The elimination of single phonon decays by the three-dimensional confinement implies a several order-of-magnitude reduction in the threshold current. The requirements on dot size (10-20nm) and on dot density and uniformity [one coupled pair of

Krystian Pracz, Martin Janssen, Peter Freche

We extend the multifractal analysis of the statistics of critical wave functions in quantum Hall systems by calculating numerically the correlations of local amplitudes corresponding to eigenstates at two different energies. Our results confirm multifractal scaling relations which are different from those occurring in conventional critical phenomena. The cri

Kyungsun Moon, Richard T. Scalettar, Gergely T. Zimanyi

We study numerically the motion of vortices in dirty type II superconductors. In two dimensions at strong driving currents, vortices form highly correlated ``static channels''. The static structure factor exhibits convincing scaling behaviour, demonstrating quasi long range translational order in the transverse direction. However order in the longitu

Claire Gardent, Michael Kohlhase

Pulman has shown that Higher--Order Unification (HOU) can be used to model the interpretation of focus. In this paper, we extend the unification--based approach to cases which are often seen as a test--bed for focus theory: utterances with multiple focus operators and second occurrence expressions. We then show that the resulting analysis favourably compares

Claire Gardent, Michael Kohlhase

In this paper, we show that Higher-Order Coloured Unification - a form of unification developed for automated theorem proving - provides a general theory for modeling the interface between the interpretation process and other sources of linguistic, non semantic information. In particular, it provides the general theory for the Primary Occurrence Restriction

Stefan Müller

I describe a very simple HPSG analysis for partial verb phrase fronting. I will argue that the presented account is more adequate than others made during the past years because it allows the description of constituents in fronted positions with their modifier remaining in the non-fronted part of the sentence. A problem with ill-formed signs that are admitted

Ehud Reiter

This is a very short paper that briefly discusses some of the tasks that NLG systems perform. It is of no research interest, but I have occasionally found it useful as a way of introducing NLG to potential project collaborators who know nothing about the field.

Edmund Grimley-Evans, George Anton Kiraz, Stephen G. Pulman

This paper describes an algorithm for the compilation of a two (or more) level orthographic or phonological rule notation into finite state transducers. The notation is an alternative to the standard one deriving from Koskenniemi's work: it is believed to have some practical descriptive advantages, and is quite widely used, but has a different interpreta

Peter Schneider, Peter Grassberger

We use the cross correlation sum introduced recently by H. Kantz to study symmetry properties of chaotic attractors. In particular, we apply it to a system of six coupled nonlinear oscillators which was shown by Kroon et al. to have attractors with several different symmetries, and compare our results with those obtained by ``detectives" in the sense of

Jukka A. Ketoja, Indubala I. Satija

The phonon modes of the Frenkel-Kontorova model are studied both at the pinning transition as well as in the pinned (cantorus) phase. We focus on the minimal frequency of the phonon spectrum and the corresponding generalized eigenfunction. Using an exact decimation scheme, the eigenfunctions are shown to have nontrivial scaling properties not only at the pin

F. Halzen

The objective of neutrino astronomy, born with the identification of thermonuclear fusion in the sun and the particle processes controlling the fate of a nearby supernova, is to build instruments which reach throughout and far beyond our Galaxy and make measurements relevant to cosmology, astrophysics, cosmic-ray and particle physics. These telescopes will p

Patrick Cote, Carlton Pryor, Robert D. McClure, J. M. Fletcher

A catalog of 383 radial velocities for red giants in the globular cluster M22 has been compiled from the literature and from new observations accumulated between 1972 and 1994. This 22-year baseline is the longest available for any sample of globular cluster stars. Using 333 repeat velocities for 109 cluster members, we have carried out a search for spectros

Patrick Cote, Phil Fischer

A search for spectroscopic binaries on the main sequence of the nearby globular cluster M4 has been undertaken with Argus, the multi-object spectrograph on the CTIO 4.0m telescope. A pair of radial velocities (median precision $\simeq$ 2 km/s) separated by 11 months have been obtained for 33 turnoff dwarfs in the magnitude range 16.9 $\le$ V $\le$ 17.4. Mont

J. -P. Lasota, R. Narayan, I. Yi

We show that the Keplerian thin disk in quiescent Soft X-ray Transients cannot extend down to the last stable orbit around the central black hole. We analyse the properties of the Narayan, McClintock & Yi (1996) model of quiescent Soft X-ray Transients in which the cold Keplerian disk has its inner edge at a large transition radius and transforms to a hot, a

Edward B. Jenkins

Most observations of absorption lines from interstellar and intergalactic matter have sufficient resolution to show most of the structure at differing radial velocities of the absorber. In analyzing the lines, however, it is important to sense and correct for the fact that some parts of a profile may have some very narrow structures that are saturated and th

M. Villar-Martin, L. Binette, R. A. E. Fosbury

In the powerful, high redshift radio galaxies, it is believed that the dominant source of ionization for the interstellar gas is the hard radiation field associated with the active nucleus. The photon source is generally external to the clouds being ionized and so the geometrical perspective from which the gas is observed and the presence and distribution of

Ted von Hippel, Gerard Gilmore, Nial Tanvir, David Robinson

Using HST and the WFPC2 we have acquired very deep V- and I-band photometry of stars in NGC 2420 and NGC 2477 to study cluster luminosity functions at approximately solar metallicity. We have determined these cluster luminosity functions down to $M_I$ = 10.5 (0.2 M$_{\odot}$) and find that the luminosity function of NGC 2420 turns over at $M_I$ $\approx$ 9.0

S. Jordan, R. Napiwotzki, D. Koester, T. Rauch

We present a LTE model atmosphere analysis of the medium and long wavelength spectrum of the cool DO white dwarf HD149499B. This observation in the spectral range 230-700 A supplements a previous analysis of an ORFEUS spectrum between 912 and 1170 A which yielded the atmospheric parameters Teff=49500+-500 K and log g = 7.97+-0.08 and a hydrogen-to-helium num

R. J. Protheroe, P. A. Johnson

We use of a hybrid matrix--Monte Carlo method to simulate the cascade through the cosmic background radiation initiated by UHE particles and radiation emitted by topological defects. We follow the cascade over cosmological distances and calculate the intensities of hadrons, gamma-rays and neutrinos produced. We compare our results with the observed cosmic ra

A. Rivero

We investigate restrictions to be imposed over the non commutative geometry model C+M_2+M_3 to make it to fit with experimental data. By constraining the action over quarks, a leptophobic Z' is got

Mark Jarrell, Hanbin Pang, D. L. Cox, K. H. Luk

The two-channel Kondo lattice model is examined with a Quantum Monte Carlo simulation in the limit of infinite dimensions. We find non-fermi-liquid behavior at low temperatures including a finite low-temperature single-particle scattering rate, the lack of a fermi edge and Drude weight. However, the low-energy density of electronic states is finite. Thus, we

Peter Filip

Aim of this work was to test the idea of J.-Y.Ollitrault about the parallel squeeze-out type of transversal flow in mid-rapidity region. For this purpose we have performed a computer simulation of the expanding pion gas created in non-central Pb-Pb 158GeV/n collisions. A squeeze-out type of asymmetry parallel to impact parameter in azimuthal distribution of

T. Asaka, Y. Shobuda, Y. Sumino

We consider a scenario where the top-quark mass is generated dynamically, and study the implication of the present experimental values for $m_t$ and the $T$ parameter. We assume technicolor-like scenario for inducing the $W$ mass and an effective four fermi operator for inducing the top-quark mass. We also assume that only this four fermi operator is relevan

Jacek Dziarmaga

1) For the hard core interaction there is some freedom left in the choice of the exact multiskyrmionic wave function's topology. The statistics of textured quasiholes, analyzed by calculation of the Berry phase, depends on this choice of topology. 2) We find a class of textured two-hole eigenstates of the Coulomb interaction. There is no definite quantum

Masayuki Tanimoto, Tatsuhiko Koike, Akio Hosoya

A complete description of dynamics of compact locally homogeneous universes is given, which, in particular, includes explicit calculations of Teichmüller deformations and careful counting of dynamical degrees of freedom. We regard each of the universes as a simply connected four dimensional spacetime with identifications by the action of a discrete subgroup

Eue Jin Jeong

The kinetic energy of a local system of objects placed in a curved spacetime is gained by the subsequent acceleration of the object following the more contracted region of spacetime. Normally this happens near massive gravitating stars. However, the gravitational dipole moment has been shown to be capable of self creating asymmetrically distorted spacetime i

C. P. Martin, Jose M. Gracia-Bondia, Joseph C. Varilly

We render a thorough, physicist's account of the formulation of the Standard Model (SM) of particle physics within the framework of noncommutative differential geometry (NCG). We work in Minkowski spacetime rather than in Euclidean space. We lay the stress on the physical ideas both underlying and coming out of the noncommutative derivation of the SM, wh

Guy D. Moore

I develop an improved Hamiltonian for classical, Minkowski Yang-Mills theory, which evolves infrared fields with corrections from lattice spacing $a$ beginning at $O(a^4)$. I use it to investigate the response of Chern-Simons number to a chemical potential, and to compute the maximal Lyapunov exponent. Both quantities have small $a$ limits, in both cases wit

Jorge L. Rodriguez

The factorization hypothesis and color-suppression are investigated by analyzing the largest, to date, sample of B mesons. In all, 20 hadronic two-body decay modes are reconstructed using 2.04 fb^-1 of data collected with the CLEOII detector. We measure the branching fraction of five class I and five class III decay modes and set upper limits on branching fr

Matthias Burkardt, Derek B. Leinweber, Xuemin Jin

The background-field formalism is used extensively in fundamental approaches to QCD to explore hadronic matrix elements of various currents. While the lattice QCD approach is formulated in the fully-interacting Hilbert space, which includes both QCD and background field interactions, the QCD sum-rule formalism is traditionally developed in the pure-QCD Hilbe

Esko Keski-Vakkuri, Samir D. Mathur

The wavefunctional in quantum gravity gives an amplitude for 3-geometries and matter fields. The four-space is usually recovered in a semiclassical approximation where the gravity variables are taken to oscillate rapidly compared to matter variables; this recovers the Schrodinger evolution for the matter. We examine turning points in the gravity variables wh

Dennis Bonatsos, C. Daskaloyannis, H. A. Mavromatis

It is proved that quasi-exactly soluble potentials corresponding to an oscillator with harmonic, quartic and sextic terms, for which the $n+1$ lowest levels of a given parity can be determined exactly, may be approximated by WKB equivalent potentials corresponding to deformed anharmonic oscillators of SU$_q$(1,1) symmetry, which have been used for the descri

Thomas Mahr, Ingo Rehberg, Alexander Groisman

The dispersion relation of surface waves of a magnetic fluid in a magnetic field is studied experimentally. We verify the theoretically predicted existence of a non-monotonic dispersion relation. In particular, we demonstrate the existence of two different wave numbers occuring at the same frequency in an annular geometry.

M. Harada, F. Sannino, J. Schechter, H. Weigel

In the framework of chiral soliton models we study the behavior of static nucleon properties under rescaling of the parameters describing the effective meson theory. In particular we investigate the question of whether the Brown--Rho scaling laws are general features of such models. When going beyond the simple Skyrme model we find that restrictive constrain

I. B. Khriplovich

Valuable information on interactions violating $P$- and $T$-invariance can be extracted from atomic experiments. The hypothesis of a large weak matrix element between single-particle states in heavy nuclei, $\sim 100$ eV, is ruled out by measurements of parity nonconservation in atoms. Experimental upper limit on the electric dipole moment of the $^{199}$Hg