September 1997 arXiv papers — page 2

A. M. Atoyan, F. A. Aharonian

Resolution of both approaching and receding ejecta in the galactic microquasars makes possible to measure the flux ratio S_a/S_r of the twin ejecta, which contains an important information about the nature of the jets. We show that the flux ratio observed from GRS 1915+105 during the prominent March/April 1994 radio flare can be explained in terms of relativ

Dörte Mehlert, Ralf Bender, Roberto P. Saglia, Gary Wegner

The Coma cluster is the ideal place to study galaxy structure as a function of environmental density in order to constrain theories of galaxy formation and evolution. Here we present the spectroscopy of 35 early type Coma galaxies, which shows that the age spread of early type galaxies in the Coma cluster is large (15 Gyrs). In contrast to the field, the dom

L. Feretti, G. Giovannini

The Coma cluster is peculiar in the radio domain owing to the presence of cluster-wide diffuse sources: the radio halo Coma C, the relic source 1253+275, and the bridge between them. Diffuse radio sources in clusters are a rare and poorly understood phenomenon. We summarize here the properties of the diffuse radio sources in Coma and their relation to other

Antoinette Songaila

The current status of high redshift D/H measurements is discussed. I first examine whether the observations of HS1937-1009 require a low value of D/H. It is shown that the LRIS measurements of the continuum break and the high resolution Lyman series data can easily be modelled with D/H in the range 5 x 10^(-5) to 10^(-4). I then discuss measurements on weake

K. Rietsch

We study the nonnegative part B_{\ge 0} of the flag variety of a reductive algebraic group G, as defined by Lusztig. Using positivity properties of the canonical basis it is shown that B_{\ge 0} has an algebraic cell decomposition indexed by pairs w\le w' of the Weyl group. This result was conjectired by Lusztig in [Lu; Progress in Math 123].

Nantel Bergeron, Frank Sottile

We show the equivalence of the Pieri formula for flag manifolds and certain identities among the structure constants, giving new proofs of both the Pieri formula and of these identities. A key step is the association of a symmetric function to a finite poset with labeled Hasse diagram satisfying a symmetry condition. This gives a unified definition of skew S

Daisuke Matsushita

In this note, we investigate fibre space structures of a projective irreducible symplectic manifold. We prove that an 2n-dimensional projective irreducible symplectic manifold admits only an n-dimensional fibration over a Fano variety which has only Q-factorial log-terminal singularities and whose Picard number is one. Moreover we prove that a general fibre

Stefan Thurner, Steven B. Lowen, Markus C. Feurstein, Conor Heneghan

Fractal and fractal-rate stochastic point processes (FSPPs and FRSPPs) provide useful models for describing a broad range of diverse phenomena, including electron transport in amorphous semiconductors, computer-network traffic, and sequences of neuronal action potentials. A particularly useful statistic of these processes is the fractal exponent $α$, which m

Stefan Thurner, Markus C. Feurstein, Malvin C. Teich

We consider the dynamic evolution of a coupled array of N multiplicative random variables. The magnitude of each is constrained by a lower bound w_0 and their sum is conserved. Analytical calculation shows that the simplest case, N=2 and w_0=0, exhibits a Lorentzian spectrum which gradually becomes fractal as w_0 increases. Simulation results for larger $N$

Thomas R. Hemmert, Barry R. Holstein, Joachim Kambor, Germar Knoechlein

We analyze polarized Compton scattering which provides information on the spin-structure of the nucleon. For scattering processes with photon energies up to 100 MeV the spin-structure dependence can be encoded into four independent parameters-the so-called spin-polarizabilities $γ_i, i=1...4$ of the nucleon, which we calculate within the framework of the &#3

John C. Collins

A proof is given that hard-scattering factorization is valid for deep-inelastic processes which are diffractive or which have some other condition imposed on the final state in the target fragmentation region.

Robert J. Scherrer, Alexander Vilenkin

We examine simulations of the formation of domain walls, cosmic strings, and monopoles on a cubic lattice, in which the topological defects are assumed to lie at the zeros of a piecewise constant 1, 2, or 3 component Gaussian random field, respectively. We derive analytic expressions for the corresponding topological defect densities in the continuum limit a

R. Akhoury, A. Sinkovics, M. G. Sotiropoulos

The wave function of a light pseudoscalar meson is considered and nonperturbative corrections as signaled by perturbation theory are calculated. Two schemes are used, the massive gluon and the running coupling scheme. Both indicate the presence of leading power corrections of ${\cal O}(b^2)$, whose exponentiation leads to a Gaussian dependence of the wave fu

A. H. Castro Neto, F. Guinea

We consider a renormalization group study of the problem of coupled stripes of holes in cuprates. We use a model of a mesh of horizontal and vertical stripes and study the problemof superconductivity via the Josephson coupling. We discuss the evolution of the Fermi surface with doping and temperature, the existence of Luttinger and/or Fermi liquid behavior,

Kim Maltman

We investigate the problem of the extraction of the isovector and isoscalar spectral functions from data on $e^+e^-\to hadrons$, in the presence of non-zero isospin breaking. It is shown that the conventional approach to extracting the isovector spectral function in the $ρ$ resonance region, in which only the isoscalar contribution associated with $ω\to ππ$

O. Philipsen, M. Teper, H. Wittig

We present the results of a detailed calculation of the excitation spectrum of states with quantum numbers J^{PC}=0++, 1-- and 2++ in the three-dimensional SU(2) Higgs model at two values of the scalar self-coupling and for fixed gauge coupling. In the context of studies of the electroweak phase transition at finite temperature these couplings correpond to t

Sanghyeon Chang, Claudio Coriano, L. E. Gordon

A study of prompt photon plus associated jet production is performed at next-to-leading order (O($αα_s^2$)) in QCD at $\sqrt{S}=200-500$ GeV, appropriate for the RHIC polarized $\vec{p}\vec{p}$ collider experiment. Momentum correlations between the jet and photon are examined and the utility of the process as a method for constraining the size and shape of t

R. Domínguez-Tenreiro, M. A. Gómez-Flechoso

In the framework of the fluctuation-dissipation approach to dynamical friction, we derive an expression giving the orbital energy exchange experienced by a compound body as it moves interacting with a non homogeneous discrete background. The body is assumed to be composed of particles endowed with a velocity spectrum and with a non homogeneous spatial distri

Eric J. Korpela, Stuart Bowyer, Jerry Edelstein

One of the keys to interpreting the character and evolution of interstellar matter in the galaxy is understanding the distribution of the low density hot (10^5 K -10^6 K) phase of the interstellar medium (ISM). This phase is much more difficult to observe than the cooler high density components of the ISM because of its low density and lack of easily observa

Eva Silverstein

I describe recent examples of phase transitions in four-dimensional M theory vacua in which the net generation number changes. There are naive obstructions to transitions lifting chiral matter, but loopholes exist which enable us to avoid them. I first review how chirality arises in the heterotic limit of M theory, previously known forms of topology change i

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

Numerical studies of lattice-gas models are well suited to describe multi-adsorbate systems. One example is the underpotential deposition of Cu on Au(111) in the presence of sulfuric acid. Preliminary results from dynamic Monte Carlo simulations of the evolution of the adsorbed layer during potential-step experiments across phase transitions are presented fo

A. Frink, J. G. Körner, J. B. Tausk

We describe in some detail the present features of an automatic loop calculation program as well as the integration techniques that go into it. The program, called XLOOPS 1.0, allows one to calculate massive one- and two-loop Feynman diagrams in the Standard Model including their tensor structure. UV divergences in UV divergent integrals are explicitly compu

Alexander Kusenko, Mikhail Shaposhnikov

Supersymmetric extensions of the standard model generically contain stable non-topological solitons, Q-balls, which carry baryon or lepton number. We show that large Q-balls can be copiously produced in the early universe, can survive until the present time, and can contribute to dark matter.

P. V. Moniz

In this report we describe quantum Reissner-Nordström (RN) black-holes interacting with a complex scalar field. Our analysis is characterized by solving a Wheeler-DeWitt equation in the proximity of an apparent horizon of the RN space-time. Subsequently, we obtain a wave-function $Ψ_{RN}[M, Q]$ representing the RN black-hole. A special emphasis is given to t

Peter Kopietz

We discuss analogies between the charge- and spin response functions of itinerant magnets. We show that the spin-analog of the charge stiffness is not given by the usual spin stiffness rho_s, but by the dynamic spin stiffness D_s, which is obtained from the dynamic spin conductance G_s (omega) in the limit of vanishing frequency omega. The low-frequency beha

A. M. Levin, M. A. Olshanetsky

We investigate the classical limit of the Knizhnik-Zamolodchikov-Bernard equations, considered as a system of non-stationar Schröodinger equations on singular curves, where times are the moduli of curves. It has a form of reduced non-autonomous hamiltonian systems which include as particular examples the Schlesinger equations, Painlevé VI equation and their

Lian Zheng, Subir Sachdev, S. Das Sarma

We present details of earlier studies (Zheng et al, Phys. Rev. Lett. 78, 310 (1997) and Das Sarma et al, ibid 79, 917 (1997)) and additional new results on double-layer quantum Hall systems at a total filling ν= 2 ν_1, where a single layer at filling ν_1 forms a ferromagnetic, fully spin-polarized, gapped incompressible quantum Hall state. For the case ν_1 =

A. Sako

A role of reducible connections in Non-Abelian Seiberg-Witten invariants is analyzed with massless Topological QCD where monopole is extended to non-Abelian groups version. By giving small external fields, we found that vacuum expectation value can be separated into a part from Donaldson theory, a part from Abelian Monopole theory and a part from non-Abelian

Sumit R. Das

Tree level decay amplitudes of near-BPS D-brane configurations are known to exactly reproduce Hawking radiation rates from corresponding black holes at low energies even though the brane configurations describe semiclassical black holes only when the open string couplings are large. We show that a large class of one (open string) loop corrections to emission

M. N. Popova, A. B. Sushkov, S. A. Golubchik, A. N. Vasil'ev

Polarized far-infrared transmittance spectra of CuGeO_3 single crystals were measured at different temperatures (6K < T < 300K). Two spectral lines, at 284.2 cm-1 in E||c polarization and at 311.7 cm-1 in E||b polarization, appear at the temperature of the spin-Peierls transition and grow in intensity with decreasing temperature. Both of them are, most proba

X. -M. Zhu, P. Ao

We investigate the problem of forces on moving vortex in a superfluid or superconductor. The main purpose is to locate the source which leads to the contradictory results in the literature. We establish the connection between this problem to the difficult but well studied subject of resistivity formula in transport theory. The relaxation time approximation u

R. Foot, R. R. Volkas, O. Yasuda

Motivated by the Exact Parity Model and other theories, the hypothesis that each of the known neutrinos oscillates maximally with a sterile partner has been put forward as an explanation of the atmospheric and solar neutrino anomalies. We provide detailed predictions for muon and electron flux ratios induced in the Kamiokande and SuperKamiokande detectors by

Jun&#39;ichi Shiraishi, Mahito Kohmoto, Kazumi Maki

Making use of the extended Ginzburg Landau theory, which includes the fourth order derivative term, we study the vortex state in a magnetic field parallel to the $ c$ axis. The vortex core structure is distorted due to this higher order term, which reveals t he fourfold symmetry. Futher, this distortion gives rise to the core interaction energy, which favo r

JLQCD Collaboration, S. Aoki, M. Fukugita, S. Hashimoto

A report is presented on our continued effort to elucidate the continuum limit of $B_K$ using the quenched Kogut-Susskind quark action. By adding to our previous simulations one more point at $β= 6.65$ employing a $56^3\times 96$ lattice, we now confirm the expected $O(a^2)$ behavior of $B_K$ with the Kogut-Susskind action. A simple continuum extrapolation q

Sergei Nayakshin, Fulvio Melia

Some recent work has shown that the spectrum of Seyfert 1 Galaxies is very similar to that of several Galactic Black Hole Candidates (GBHCs) in their hard state. However, the smallness of the observed reflection component in Cygnus X-1, in addition to other constraints, seem to rule out the two-phase model (otherwise successful in the case of Seyfert Galaxie

Akihide Hanaki, Masahiko Miyamoto, Daisuke Tambara

We prove the Galois correspondence between the subgroups of a finite automorphism group G of a simple vertex operator algebra V and the vertex operator subalgebras of V containing the set V^G of G-invariants.

Kenji Kajiwara, Yasuhiro Ohta

Rational solutions for the Painlevé IV equation are investigated by Hirota bilinear formalism. It is shown that the solutions in one hierarchy are expressed by 3-reduced Schur functions, and those in another two hierarchies by Casorati determinant of the Hermite polynomials, or by special case of the Schur polynomials.

Adan Cabello, Emilio Santos

We exhibit a local-hidden-variable model in agreement with the results of the two-photon coincidence experiment made by Torgerson et al. [Phys. Lett. A 204 (1995) 323]. The existence of any such model shows that the experiment does not exclude local realism.

Adan Cabello, Guillermo Garcia-Alcaine

The Einstein-Podolsky-Rosen argument on quantum mechanics incompleteness is formulated in terms of elements of reality inferred from joint (as opposed to alternative) measurements, in two examples involving entangled states of three spin-1/2 particles. The same states allow us to obtain proofs of the incompatibility between quantum mechanics and elements of

V. G. Bagrov, V. V. Belov, M. M. Nikitin, A. Yu. Trifonov

The first order quantum correction to the power of spontaneous radiation of electrons in an arbitrary two-component periodic magnetic field was obtained. The phenomenon of selfpolarization of the spin of electrons in a process of spontaneous radiation was also studied. By electron&#39;s motion in a spiral magnetic undulator, the quantitative characteristics

Martti Havukainen, Stig Stenholm

A new method to calculate the spectrum using cascaded open systems and master equations is presented. The method uses two state analyzer atoms which are coupled to the system of interest, whose spectrum of radiation is read from the excitation of these analyzer atoms. The ordinary definitions of a spectrum uses two-time averages and Fourier-transforms. The p

Igor Frenkel, Mikhail Khovanov, Alexander Kirillov

In this paper we show that the Kazhdan-Lusztig polynomials (and, more generally, parabolic KL polynomials) for the group $S_n$ coincide with the coefficients of the canonical basis in $n$th tensor power of the fundamental representation of the quantum group $U_q sl_k$. We also use known results about canonical bases for $U_q sl_2$ to get a new proof of recur

Maxim Kontsevich

I prove that every finite-dimensional Poisson manifold X admits a canonical deformation quantization. Informally, it means that the set of equivalence classes of associative algebras close to the algebra of functions on X is in one-to-one correspondence with the set of equivalence classes of Poisson structures on X modulo diffeomorphisms. In fact, a more gen

Holger F. Hofmann, Ortwin Hess

It is shown that the interference between spontaneous emission into the non-lasing supermode and the laser field of a semiconductor laser array causes spatial holeburning which couples the dynamics of the spontaneous emission with the laser field. In particular, phase locking between the spontaneous emission and the lasing mode leads to the formation of a sp

F. M. Nunes, R. Crespo, I. J. Thompson

Quadrupole and octupole couplings to all bound states of $^7$Be are included in describing the capture reaction $^7$Be$(p,γ)^8$B. We verify, contrary to what we had initially stated, that the energy behaviour of the Astrophysical S-factor in the energy range of interest is not significantly sensitive to the core couplings in the g.s. (g.s.) of $^8$B although

K. Hagino, N. Takigawa, S. Kuyucak

Recently measured high precision data of fusion excitation function have enabled a detailed study on the effects of nuclear collective excitations on fusion reactions. Using such highly accurate data of the $^{16}$O + $^{144,148}$Sm reactions, we discuss the anharmonic properties of collective phonon excitations in $^{144,148}$Sm nuclei. It is shown that sub

O. Hanstein, D. Drechsel, L. Tiator

We have analysed pion photoproduction imposing constraints from fixed t dispersion relations and unitarity. Coupled integral equations for the S and P wave multipoles were derived from the dispersion relations and solved by the method of Omnes and Muskhelishvili. The free parameters were determined by a fit to the most recent data for π^{+} and π^{0} product

D. R. Phillips, S. R. Beane, T. D. Cohen

Some form of nonperturbative regularization is necessary if effective field theory treatments of the NN interaction are to yield finite answers. We discuss various regularization schemes used in the literature. Two of these methods involve formally iterating the divergent interaction and then regularizing and renormalizing the resultant amplitude. Either a (

K. Arita, A. Sugita, K. Matsuyanagi

By means of periodic orbit theory and deformed cavity model, we have investigated semiclassical origin of superdeformed shell structure and also of reflection-asymmetric deformed shapes. Systematic analysis of quantum-classical correspondence reveals that bifurcation of equatorial orbits into three-dimensional ones play predominant role in the formation of t

Zygmunt Lalak, Andre&#39; Lukas, Burt A. Ovrut

We explicitly construct soliton solutions in the low energy description of M-theory on S^1/Z_2. It is shown that the 11-dimensional membrane is a BPS solution of this theory if stretched between the Z_2 hyperplanes. A similar statement holds for the 11-dimensional 5--brane oriented parallel to the hyperplanes. The parallel membrane and the orthogonal 5-brane

Dmitri Fursaev

The relation between the covariant Euclidean free-energy $F^E$ and the canonical statistical-mechanical free energy $F^C$ in the presence of the Killing horizons is studied. $F^E$ is determined by the covariant Euclidean effective action. The definition of $F^C$ is related to the Hamiltonian which is the generator of the evolution along the Killing time. At

R. Jackiw

The present-day crisis in quantum field theory is described.

Hirosi Ooguri

Talk presented at Strings `97 in Amsterdam (June 16 - 21, 1997)

N. Gurappa, Prasanta K. Panigrahi, V. Srinivasan

The degeneracy structure of the eigenspace of the N-particle Calogero-Sutherland model is studied from an algebraic point of view. Suitable operators satisfying SU(2) algebras and acting on the degenerate eigenspace are explicitly constructed for the two particle case and then appropriately generalized to the N-particle model. The raising and lowering operat

E. S. Moreira, Jnr

Motion of a non-relativistic particle on a cone with a magnetic flux running through the cone axis (a ``flux cone&#39;&#39;) is studied. It is expressed as the motion of a particle moving on the Euclidean plane under the action of a velocity-dependent force. Probability fluid (``quantum flow&#39;&#39;) associated with a particular stationary state is studied

V. E. Korepin, N. A. Slavnov

We study models of quantum statistical mechanics which can be solved by the algebraic Bethe ansatz. The general method of calculation of correlation functions is based on the method of determinant representations. The auxiliary Fock space and auxiliary Bose fields are introduced in order to remove the two body scattering and represent correlation functions a

Renata Kallosh

Killing spinors of space-time BPS configurations play an important role in quantization of theories with the fermionic worldvolume local symmetry. We show here how it works for the GS superstring, BST supermembrane and M-5-brane. We show that the non-linear generalization of the (2,0) d=6 tensor supermultiplet action is the M-5-brane action in a Killing gaug

E Rodulfo, R Delbourgo

We exhibit the one-loop multi-gluon effective Lagrangian in any dimension for a field theory with a quasilocal background, using the background-field formalism. Specific results, including counter terms (up to 12 spacetime dimensions), have been derived, applied to the Yang-Mills theory and found to be in agreement with other string-inspired approaches.

Vipul Periwal

The nontrivial transformation of the phase space path integral measure under certain discretized analogues of canonical transformations is computed. This Jacobian is used to derive a quantum analogue of the Hamilton-Jacobi equation for the generating function of a canonical transformation that maps any quantum system to a system with a vanishing Hamiltonian.

M. Jamin, A. Pich

The mass of the bottom quark (both the pole mass $M_b$ and the $\MSb$ mass $m_b$) and the strong coupling constant $α_s$ have been determined from QCD moment sum rules for the $Υ$ system. In the pole-mass scheme large perturbative corrections resulting from coulombic contributions have been resummed. The results of this analysis are: $M_b=4.60 \pm 0.02 \gev$

C. Giunti, C. W. Kim, U. W. Lee

In order to investigate when neutrinos cease to oscillate in the framework of quantum field theory, we have reexamined the wave packet treatment of neutrino oscillations by taking different sizes of the wave packets of the particles involved in the production and detection processes. The treatment is shown to be considerably simplified by using the Grimus-St

Bodo Lampe

New interactions in top-quark production and decay are studied under the conditions of the Tevatron upgrade. Studying the process q qbar --> t tbar --> b mu nu tbar, it is shown how the lepton rapidity and transverse energy distribution are modified by nonstandard modifications of the g-t-tbar and the t-b-W vertex.

A. I. Sanda, Zhi-zhong Xing

In anticipation for intensive experimental effort on B physics, theorists have introduced many ingenious ways to measure properties of the unitarity triangle. We review some of these methods. We will be critical in the hope that, if there is any defect in them, it can be remedied either theoretically or experimentally.

Gerhard A. Schuler

Recent progress in the factorization of exclusive decays of heavy quarkonia into long-distance and short-distance contributions is presented. The role of higher Fock states and colour-octet contributions is outlined.

S. Peris

I report on some recent work done in collaboration with E. de Rafael on the connection between ultraviolet renormalons in QCD and Nambu-Jona-Lasinio-like Lagrangians as its effective description at low energies.

A. Dumitru, M. Bleicher, S. A. Bass, C. Spieles

Direct photon production in central Pb+Pb collisions at CERN-SPS energy is calculated within the relativistic microscopic transport model UrQMD, and within distinctly different versions of relativistic hydrodynamics. We find that in UrQMD the local momentum distributions of the secondaries are strongly elongated along the beam axis initially. Therefore, the

D. Cocolicchio, L. Telesca, M. Viggiano

The peculiar features of the mixing in the neutral pseudoscalar mesons K0--antiK0 can be introduced by the analogy to the optical polarization. The time-reversed not-invariant processes and the related phenomenon of CP-nonconservation can be then joined to the dissipative effects which yield a not vanishing imaginary part in the relevant propagation of elect

V. Berezinsky, M. Kachelriess

We argue that the lightest supersymmetric particles (LSP) can be produced with extremely high energies $E\gsim 10^{10}$ GeV in the Universe at the present epoch. Their most probable sources are decaying superheavy particles produced by topological defects or as relic Big Bang particle. We discuss the mechanisms of production of LSP at ultra-high energies (UH

M. Jamin

The talk discusses preliminary results of an updated analysis of the strange quark mass from the scalar current QCD sum rules [1]. In particular the role of the scalar form factor which is a main ingredient in the analysis is especially emphasised. The sources of the uncertainties in the sum rule determination are briefly reviewed.

Martina M. Brisudova, Sergio Szpigel, Robert J. Perry

A constituent parton picture of hadrons with logarithmic confinement arises naturally in light-front QCD when the hamiltonian is computed using a perturbative renormalization group; however, rotational symmetry is not manifest as a simple kinematic symmetry. Relevant operators must typically be fine-tuned when a perturbative renormalization group is used, an

Yoshio Kikukawa

Dynamical nature of the gauge degrees of freedom and its effect to fermion spectrum are studied at $β=\infty$ for two- and four-dimensional nonabelian chiral gauge theories in the vacuum overlap formalism. It is argued that the disordered gauge degrees of freedom does not contradict to the chiral spectrum of lattice fermion.

Yoshio Kikukawa, Herbert Neuberger

A certain U(1) model in 2 dimensions, describing four right handed unit charged Weyl fermions interacting with one doubly charged left handed Weyl fermion, is exactly soluble and has massless Majorana-Weyl composites. Instanton induced fermion number violation is essential for &#39;t Hooft anomaly consistency. The associated &#39;t Hooft vertex can be analyt

C. Legeland, B. Beinlich, M. Lütgemeier, A. Peikert

We report a method to select optimal smearing parameters before production runs and discuss the advantages of this selection for the determination of the string tension.

Dmitry Pekurovsky, Greg Kilcup

We report progress in our lattice study of hadronic weak matrix elements relevant for the Delta I = 1/2 rule and epsilon-prime. The presented results are from our first runs on a quenched ensemble with beta=6.0 and a dynamical Nf=2 ensemble with beta=5.7, using staggered gauge-invariant tadpole-improved operators.

E. Mendel, M. Nest

A new formalism will be presented in order to study real time evolution of quantum systems at finite temperature. Probability distributions for time-correlated observables will be studied non-perturbatively and fully quantized. This works for various systems, including ones with tunneling phenomena. We have obtained good results with some computational metho

N. Eicker, W. Bietenholz, A. Frommer, H. Hoeber

We generalize local lexicographic SSOR preconditioning for the Sheikholeslami-Wohlert improved Wilson fermion action and the truncated perfect free fermion action. In our test implementation we achieve performance gains as known from SSOR preconditioning of the standard Wilson fermion action.

C. Bernard, T. DeGrand, C. DeTar, Steven Gottlieb

MILC collaboration results for \fB, \fBs, \fD, \fDs and their ratios are presented. These results are still preliminary, but the analysis is close to being completed. Sources of systematic error, both within the quenched approximation and from quenching itself, are estimated. We find, for example, $f_B=153\pm 10 {}^{+36}_{-13} {}^{+13}_{-0} MeV$, and $f_{B_s

Adrian L. Kaehler

The QCD phase transition is studied on 32^3x8 quenched lattices. One expects from simple arguments that the quenched chiral condensate should diverge as the chiral limit is approached. Previous studies have not been able to observe this behavior, perhaps due to relatively large lattice spacings used. The topic is revisited here on N_t=8 lattices, where the p

M. Feurstein, E. -M. Ilgenfritz, H. Markum, M. Müller-Preussker

In an attempt to describe the change of topological structure of pure SU(2) gauge theory near deconfinement a renormalization group inspired method is tested. Instead of cooling, blocking and subsequent inverse blocking is applied to Monte Carlo configurations to capture topological features at a well-defined scale. We check that this procedure largely conse

PACS Collaboration, S. Aoki, G. Boyd, R. Burkhalter

The quenched hadron spectrum in the continuum obtained with the Wilson quark action in recent simulations on the CP-PACS is presented. Results for the light quark masses and the QCD scale parameter are reported.

A. Spitz, N. Eicker, J. Fingberg, S. Güsken

We present results for the b \bar b spectrum obtained using an O(M_bv^6)-correct non-relativistic lattice QCD action. Propagators are evaluated on SESAM&#39;s three sets of dynamical gauge configurations generated with two flavours of Wilson fermions at beta = 5.6. Compared to a quenched simulation at equivalent lattice spacing we find better agreement of ou

SESAM, TkL collaborations, :, H. Hoeber

We present results for spectroscopy, quark masses and decay constants obtained from SESAM&#39;s and TkL&#39;s large statistics simulations of QCD with two dynamical Wilson fermions.

J. A. Crittenden

We present results from recent investigations of diffractive vector meson production using the ZEUS detector at HERA. These consist of measurements of rho production in the region of photon virtuality 0.25 < Q^2 < 0.85 GeV^2, of rho, phi, and J/psi production for values of the momentum transfer to the proton 0.3 < |t| < 4.0 GeV^2, and of elastic J/psi produc

Michael Kuhlen

Measurements of the hadronic final state at HERA are reviewed, which aim at the investigation of the parton dynamics of the proton at small Bjorken x.

Pawel O. Mazur

The decay rate for a black hole to decay nonperturbatively via tunneling is shown to be related to the Bekenstein-Hawking black hole entropy $S_{bh}$. This new physical interpretation of the black hole entropy was presented first in 1988 in this paper. I quote here the relevant statement: ``It should be noticed that the decay rate of a black hole due to nonp

Mirta S. Iriondo, Enzo O. Leguizamón, Oscar A. Reula

We apply recent results in the theory of PDE, specifically in problems with two different time scales, on Einstein&#39;s equations near their Newtonian limit. The results imply a justification to Postnewtonian approximations when initialization procedures to different orders are made on the initial data. We determine up to what order initialization is needed

Lee Samuel Finn

Data analysis is the application of probability and statistics to draw inference from observation. Is a signal present or absent? Is the source an inspiraling binary system or a supernova? At what point in the sky is the radiation incident from? In these notes I want to address how two different statistical methodologies --- Bayesian and Frequentist --- appr

Dusa McDuff, Dietmar Salamon

This contains a list of (mostly very minor) corrections to the book Introduction to Symplectic Topology, Clarendon Press, Oxford, (1995), together with rewritten versions of two lemmas and some additional comments.

Riccardo Mannella

Numerical algorithms for the integration of stochastic differential equations in the presence of white noise are introduced and compared. Algorithms for the integration of stochastic correlated forces are also briefly reviewed. Finally, a specialised algorithm for two dimensional systems is derived, having in mind the integration of particles in the liquid s

J. M. Tranquada

Neutron scattering experiments have played a crucial role in characterizing the spin and charge correlations in copper-oxide superconductors. While the data are often interpreted with respect to specific theories of the cuprates, an attempt is made here to distinguish those facts that can be extracted empirically, and the connections that can be made with mi

A. Minguzzi, M. P. Tosi

A linear response framework is set up for the evaluation of collective excitations in a confined vapour of interacting Bose atoms at finite temperature. Focusing on the currently relevant case of contact interactions between the atoms, the theory is developed within a random phase approximation with exchange. This approach is naturally introduced in a two-fl

E. Akkermans, R. Narevich

A quantum mesoscopic billiard can be viewed as a bounded electronic system due to some external confining potential. Since, in general, we do not have access to the exact expression of this potential, it is usually replaced by a set of boundary conditions. We discuss, in addition to the standard Dirichlet choice, the other possibilities of boundary condition

Michael Kotelyanskii, Sanat K. Kumar

Thin films of binary mixtures that interact through isotropic forces and directionally specific &#34;hydrogen bonding&#34; are considered through Monte Carlo simulations. We show, in good agreement with experiment, that the single phase of these mixtures can be stabilized or destabilized on confinement. These results resolve a long standing controversy, sinc

Sergey N. Rashkeev, Walter R. L. Lambrecht, Benjamin Segall

LMTO calculations are presented for the frequency dependent second harmonic generation (SHG) in the polytypes 2H, 4H, 6H, 15R and 3C of SiC. All independent tensor components are calculated. The spectral features and the ratios of the 333 to 311 tensorial components are studied as a function of the degree of hexagonality. The relationship to the linear optic

Raffaele Esposito, Joel L. Lebowitz, Rossana Marra

We consider a gas in a horizontal slab, in which the top and bottom walls are kept at different temperatures. The system is described by the Boltzmann equation (BE) with Maxwellian boundary conditions specifying the wall temperatures. We study the behavior of the system when the Knudsen number $ε$ is small and the temperature difference between the walls as

P. R. A. Campos, R. N. Onody

We extend the Wolff algorithm to include correlated spin interactions in diluted magnetic systems. This algorithm is applied to study the site-bond-correlated Ising model on a two dimensional square lattice. We use a finite size scaling procedure to obtain the phase diagram in the temperature-concentration (Tc,C) space. We also have verified that the autocor

R. G. Mints, I. B. Snapiro

Critical temperature reduction $ΔT_c$ is considered for a thin film of a layered superconductor (S) with a rough surface covered by a thick layer of a normal metal (N). The roughness of the SN interface increases the penetration of electrons from the normal metal into the superconductor and leads to an enhancement of the proximity effect. The value of $ΔT_c$

D. P. Chu, M. G. Dowsett

We demonstrate the use of maximum entropy based deconvolution to reconstruct boron spatial distribution from the secondary ion mass spectrometry (SIMS) depth profiles on a system of variously spaced boron $δ$-layers grown in silicon. Sample independent response functions are obtained using a new method which reduces the danger of incorporating real sample be

A. Bäcker, R. Schubert, P. Stifter

For a large class of quantized ergodic flows the quantum ergodicity theorem due to Shnirelman, Zelditch, Colin de Verdi\`ere and others states that almost all eigenfunctions become equidistributed in the semiclassical limit. In this work we first give a short introduction to the formulation of the quantum ergodicity theorem for general observables in terms o

L. Armus, B. T. Soifer, T. W. Murphy, G. Neugebauer

We have imaged the z=3.594 radio galaxy 4C +19.71 in the light of the redshifted [OIII] 5007 angstrom emission line, using a narrow-band filter centered at 2.3 microns with the Near Infrared Camera on the Keck Telescope. The [OIII] nebula of 4C +19.71 has a size of 74 x 9 kpc, and a luminosity of 3 x 10^37 W. The rest frame equivalent width of the 5007 line,