October 1998 arXiv papers — page 8

Colin J. Morningstar, J. Shigemitsu

The temporal and spatial components of the heavy-light vector current and the spatial components of the axial current are expressed in terms of lattice-regulated operators suitable for simulations of B and D mesons. The currents are constructed by matching the appropriate scattering amplitudes in continuum QCD and a lattice model to one-loop order in perturb

Xiang-Qian Luo, J. Jiang, S. Guo, J. Li

We study QCD in 2 dimensions using the improved lattice fermionic Hamiltonian proposed by Luo, Chen, Xu and Jiang. The vector mass and the chiral condensate are computed for various $SU(N_C)$ gauge groups. We do observe considerable improvement in comparison with the Wilson quark case.

Rajamani Narayanan

Recent results on the spectral properties of the Hermitian Wilson-Dirac operator are presented.

I. V. Kanatchikov

An approach to quantization of fields and gravity based on the De Donder-Weyl covariant Hamiltonian formalism is outlined. It leads to a hypercomplex extension of quantum mechanics in which the algebra of complex numbers is replaced by the space-time Clifford algebra and all space-time variables enter on equal footing. A covariant hypercomplex analogue of th

Gérard Clément

Static horizonless solutions to the Einstein--Maxwell field equations, with only a circular cosmic string singularity, are extended to exact rotating asymptotically flat solutions. The possible interpretation of these field configurations as spinning elementary particles or as macroscopic rotating cosmic rings is discussed.

Hans-Peter Nollert, Richard H. Price

Computations of the strong field generation of gravitational waves by black hole processes produce waveforms that are dominated by quasinormal (QN) ringing, a damped oscillation characteristic of the black hole. We describe here the mathematical problem of quantifying the QN content of the waveforms generated. This is done in several steps: (i) We develop th

Joseph O'Rourke

The proof of Dey's new k-set bound is illustrated.

Joseph O'Rourke

Several recent SIGGRAPH papers on surface simplification are described.

M. R. Evans, N. Rajewsky, E. R. Speer

We present an exact solution of a probabilistic cellular automaton for traffic with open boundary conditions, e.g. cars can enter and leave a part of a highway with certain probabilities. The model studied is the asymmetric exclusion process (ASEP) with {\it simultaneous} updating of all sites. It is equivalent to a special case ($v_{\rm max}=1$) of the Nage

Aleksandar Donev, Jeff Rockwell, Daniel ben-Avraham

We study diffusion-limited coalescence, A+A<-->A, in one dimension, in the presence of a diffusing trap. The system may be regarded as a generalization of von Smoluchowski&#39;s model for reaction rates, in that: (a) it includes reactions between the particles surrounding the trap, and (b) the trap is mobile -- both considerations which render the model more

Sasha Dukan, Oskar Vafek

We present a detailed numerical calculation of the upper critical field $H_{c2}(T)$ for a bulk extreme type-II superconductor. Particular emphasis is placed on the high-field, low-temperature regime of the HT-phase diagram. In this regime it is necessary to go beyond the standard semi-classical theory and include the effects of Landau quantization of the ele

Dmitry N. Chigrin, Andrei V. Lavrinenko

It is shown that total reflection for all incident angles does not require a two- or three-dimensional photonic crystal. We demonstrate that a one-dimensional photonic crystal can exhibit total omni-directional reflection for any incident wave within some frequency region. The formation of the omni-directional gap is discussed and a wide range of realistic f

M. Calandra, F. Becca, S. Sorella

We have studied the t-J model using the Green Function Monte Carlo technique. We have obtained accurate energies well converged in the thermodynamic limit, by performing simulations up to 242 lattice sites. By studying the energy as a function of hole doping we conclude that there is no phase separation in the physical region, relevant for HTc superconductor

B. -Y. Ha, D. Thirumalai

We calculate the dependence of the electrostatic persistence length, l_e, of weakly charged flexible polyelectrolyte chains using a self-consistent variational theory. The variation of l_e with κ, the inverse Debye screening length, is controlled by the parameter l_0 l_B/A^2, where l_0 is the bare persistence length, l_B is the Bjerrum length, and A is the m

L. Martin-Moreno, F. J. Garcia-Vidal, A. M. Somoza

We propose systems with structures defined by self-assembled triply periodic minimal surfaces (STPMS) as candidates for photonic bandgap materials. To support our proposal we have calculated the photonic bands for different STPMS and we have found that, at least, the double diamond and gyroid structures present full photonic bandgaps. Given the great variety

S. I. Jury, P. Bladon, S. Krishna, M. E. Cates

We simulate late-stage coarsening of a 3-D symmetric binary fluid. With reduced units l,t (with scales set by viscosity, density and surface tension) our data extends two decades in t beyond earlier work. Across at least four decades, our own and others&#39; individual datasets (< 1 decade each) show viscous hydrodynamic scaling (l ~ a + b t), but b is not c

Kasper Astrup Eriksen, Per Hedegård

We clarify the path integral calculation, recently suggested by Golubev and Zaikin, and show, contrary to their claim, that quasiparticles become fully coherent quantum particles in the $T \to 0$ limit. The important physical point is the inclusion of the recoil of the quasiparticle when interacting with fluctuations in the rest of the Fermi gas.

G. Kasner, Z. Papadopolos, P. Kramer, D. E. B&#34;urgler

A Fibonacci-like terrace structure along a 5fold axis of i-Al(68)Pd(23)Mn(9) monograins has been observed by T.M. Schaub et al. with scanning tunnelling microscopy (STM). In the planes of the terraces they see patterns of dark pentagonal holes. These holes are well oriented both within and among terraces. In one of 11 planes Schaub et al. obtain the autocorr

David P. DiVincenzo

Many things will have to go right for quantum computation to become a reality in the lab. For any of the presently-proposed approaches involving spin states in solids, an essential requirement is that these spins should be measured at the single-Bohr-magneton level. Fortunately, quantum computing provides a suggestion for a new approach to this seemingly alm

Debashish Chowdhury, Abhay Pasupathy, Shishir Sinha

In the Nagel-Schreckenberg model of vehicular traffic on single-lane highways vehicles are modelled as particles which hop forward from one site to another on a one dimensional lattice and the inter-particle interactions mimic the manner in which the real vehicles influence each other&#39;s motion. In this model the number of empty lattice sites in front of

Jose D. Munoz, Hans J. Herrmann

We propose a way of extending the Broad Histogram Monte Carlo method (BHMC) to systems with continuous degrees of freedom, and we apply these ideas to investigate the three-dimensional XY-model. Our method gives results in excellent agreement with Metropolis and Histogram Monte Carlo simulations and calculates for the whole temperature range 1.2<T<4.7 using

M. K. Aliev, G. R. Alimov, T. M. Muminov, B. A. Olimov

A high-Tc, superconducting Ho-Ba-Cu-O single crystal with Tc=86.8 K is investigated on a modified ESR spectrometer at temperatures T>78 K. A signal is observed, whose spectrum in the range of magnetic fields H<0.7 Oe has the form of equivalent absorption lines with an interval Δ= 0.009 Oe. Detailed measurements of the dependence of the spectrum on the amplit

J. -B. Fournier

A phenomenological Landau elasticity for the shape, dilation, and lipid-tilt of bilayer membranes is developed. The shape mode couples with the sum of the monolayers&#39; tilt, while the dilation mode couples with the difference of the monolayers&#39; tilts. Interactions among membrane inclusions within regular arrays are discussed. Inclusions modifying the

T. H. Hansson, A. Karlhede, J. M. Leinaas, U. Nilsson

We propose a new effective field theory for partially polarized quantum Hall states. The density and polarization for the mean field ground states are determined by couplings to two Chern-Simons gauge fields. In addition there is a $σ$-model field, $\mh$, which is necessary both to preserve the Chern-Simons gauge symmetry that determines the correlations in

Siun-Chuon Mau, David A. Huse

Classical hard spheres crystallize at equilibrium at high enough density. Crystals made up of stackings of 2-dimensional hexagonal close-packed layers (e.g. fcc, hcp, etc.) differ in entropy by only about $10^{-3}k_B$ per sphere (all configurations are degenerate in energy). To readily resolve and study these small entropy differences, we have implemented tw

M. Vendruscolo, B. Subramanian, I. Kanter, E. Domany

A contact map is a simple representation of the structure of proteins and other chain-like macromolecules. This representation is quite amenable to numerical studies of folding. We show that the number of contact maps corresponding to the possible configurations of a polypeptide chain of N amino acids, represented by (N-1)-step self avoiding walks on a latti

M. J. Steel, Weiping Zhang

We consider stationary and propagating solutions for a Bose-Einstein condensate in a periodic optical potential with an additional confining optical or magnetic potential. Using an effective mass approximation we express the condensate wavefunction in terms of slowly-varying envelopes modulating the Bloch modes of the optical lattice. In the limit of a weak

S. C. Trager, J. J. Dalcanton, B. J. Weiner

We present first results from an on-going survey of the stellar populations of the bulges and inner disks of spirals at various points along the Hubble sequence. In particular, we are investigating the hypotheses that bulges of early-type spirals are akin to (and may in fact originally have been) intermediate-luminosity ellipticals while bulges of late-type

Schuyler D. Van Dyk, Chien Y. Peng, Aaron J. Barth, Alexei V. Filippenko

The locations of supernovae in the local stellar and gaseous environment in galaxies contain important clues to their progenitor stars. As part of a program to study the environments of supernovae using Hubble Space Telescope (HST) imaging data, we have examined the environment of the Type II-L SN 1979C in NGC 4321 (M100). We place more rigorous constraints

C. Graziani, D. Q. Lamb, G. H. Marion

We present a rigorous method, based on Bayesian inference, for calculating the odds favoring the hypothesis that any particular class of astronomical transients produce gamma-ray bursts over the hypothesis that they do not. We then apply this method to a sample of 83 Type Ia supernovae and a sample of 20 Type Ib-Ic supernovae. We find overwhelming odds again

J. C. Mather, D. J. Fixsen, R. A. Shafer, C. Mosier

The photometric errors of the external calibrator for the FIRAS instrument on the COBE are smaller than the measurement errors on the cosmic microwave background (CMBR) spectrum (typically 0.02 MJy/sr, 1 sigma), and smaller than 0.01% of the peak brightness of the CMBR. The calibrator is a re-entrant cone, shaped like a trumpet mute, made of Eccosorb iron-lo

Hien T. Nguyen, Peter R. Eisenhardt, Michael W. Werner, Robert Goodrich

We present imaging polarimetry of the extremely luminous, redshift 2.3 IRAS source FSC10214+4724. The observations were obtained with HST&#39;s Faint Object Camera in the F437M filter, which is free of strong emission lines. The 0.7 arcsec long arc is unresolved to 0.04 arcsec FWHM in the transverse direction, and has an integrated polarization of 28 +/- 3 p

N. D. Ramesh Bhat, A. Pramesh Rao, Yashwant Gupta

Refractive interstellar scintillation (RISS) is thought to be the cause behind a variety of phenomena seen at radio wavelengths in pulsars and compact radio sources. Though there is substantial observational data to support several consequences of it, the quantitative predictions from theories have not been thoroughly tested. In this paper, data from our lon

F. Halzen

1. Overview of neutrino astronomy: multidisciplinary science. 2. Cosmic accelerators: the highest energy cosmic rays. 3. Neutrino beam dumps: supermassive black holes and gamma ray bursts. 4. Neutrino telescopes: water and ice. 5. Indirect dark matter detection. 6. Towards kilometer-scale detectors.

Q. Daniel Wang

Recent ROSAT and ASCA X-ray observations as well as HST images have provided new insights into the structure and evolution of the 30 Dor nebula. I review hot gas properties of the nebula and discuss related physical processes. The structure of the nebula can be understood as outflows of hot and HII gases from the parent giant molecular cloud of R136. The dyn

Gustavo Medina Tanco

Seven and a half years of continuous monitoring of giant air showers triggered by ultra high-energy cosmic rays have been recently summarized by the AGASA collaboration. The resulting energy spectrum indicates clearly that the cosmic ray spectrum extends well beyond the Greisen-Zatsepin-Kuzmin (GZK) cut-off at $\sim 5 \times 10^{19}$ eV. Furthermore, despite

Q. Daniel Wang, E. V. Gotthelf

Based on a deep ROSAT HRI observation, we have detected a pulsed signal in the 0.1-2 keV band from PSR J0537-6910 --- the recently discovered pulsar associated with the supernova remnant N157B in the Large Magellanic Cloud. The measured pulse period 0.01611548182 ms (+- 0.02 ns), Epoch MJD 50540.5, gives a revised linear spin-down rate of $5.1271 \times 10^{

P. P. Avelino, J. P. M. de Carvalho

We study the growth of linear perturbations induced by a generic causal scaling source as a function of the cosmological parameters $h$, $Ω^m_0$ and $Ω^Λ_0$. We show that for wavenumbers $k \gsim 0.01 h/Mpc$ the spectrum of density and velocity perturbations scale in a similar way to that found in inflationary models with primordial perturbations. We show th

Stacy McGaugh

Our view of the properties of galaxies is strongly affected by the way in which we survey for them. I discuss some aspects of selection effects and methods to compensate for them. One result is an estimate of the surface brightness distribution. I believe this is progress, but considerable uncertainty remains.

N. D. Ramesh Bhat, Yashwant Gupta, A. Pramesh Rao

Refractive scintillation effects are powerful techniques for discriminating between different models proposed for the electron density fluctuation spectrum in the ISM. Data from our long-term scintillation study of 18 pulsars in the DM range 3-35 pc cm^{-3} (Paper I) are used to investigate two important observable effects of refractive scintillation: (i) mo

Shmuel Balberg, Itamar Lichtenstadt, Gregory. B. Cook

We examine the roles the presence of hyperons in the cores of neutron stars may play in determining global properties of these stars. The study is based on estimates that hyperons appear in neutron star matter at about twice the nuclear saturation density, and emphasis is placed on effects that can be attributed to the general multi-species composition of th

John M. Porter

The effect of rotation of a star on the distribution of chemical species in radiative zones is discussed. Gravity darkening generates a large radiative force on heavy element ions which is directed toward the equatorial plane. Taking iron as an example, it is shown that this force may produce drift velocities similar to, and larger than, the typical velociti

T. J. Ponman, D. B. Cannon, J. F. Navarro

It is widely believed that structure in the Universe evolves hierarchically, as primordial density fluctuations, amplified by gravity, collapse and merge to form progressively larger systems. The structure and evolution of X-ray clusters, however, seems at odds with this hierarchical scenario for structure formation. Poor clusters and groups, as well as most

Gavin Ramsay, David A. H. Buckley, Mark Cropper, M. K. Harrop-Allin

Following the suggestion of Schwope et al that the magnetic cataclysmic variable RX J2115-5840 maybe a near-synchronous polar, we obtained optical polarimetry of this system over a 2 week period. From a power spectrum of the circular polarimetry data we determine that the spin period of the white dwarf and the binary orbital period which differ by 1.2%. RX J

Jongsoo Kim, Dongsu Ryu, T. W. Jones, S. S. Hong

We present a multi-dimensional numerical code to solve isothermal magnetohydrodynamic (IMHD) equations for use in modeling astrophysical flows. First, we have built a one-dimensional code which is based on an explicit finite-difference method on an Eulerian grid, called the total variation diminishing (TVD) scheme. Recipes for building the one-dimensional IM

N. D. Ramesh Bhat, A. Pramesh Rao, Yashwant Gupta

We report long-term scintillation observations of 18 pulsars in the DM range 3-35 pc cm^{-3} carried out during 1993-1995 using the Ooty Radio Telescope at 327 MHz. These observations were made with the aim of studying refractive effects in pulsar scintillation, and obtaining reliable estimates of diffractive and refractive scintillation properties. Dynamic

John J. Salzer, Stuart A. Norton

We analyze deep CCD images of nearby Blue Compact Dwarf (BCD) galaxies in an attempt to understand the nature of the progenitors which are hosting the current burst of star formation. In particular, we ask whether BCDs are hosted by normal or low-surface-brightness dI galaxies. We conclude that BCDs are in fact hosted by gas-rich galaxies which populate the

Scott C. Chapman, Simon L. Morris, Gordon A. H. Walker

As part of a project to map nearby Seyfert galaxies in the near-IR with adaptive optics, we present high spatial resolution, near-IR images in J,H, and K of the nuclei of NGC 3227 and NGC 2992, obtained with the Adaptive Optics Bonnette (AOB) on CFHT. The ~0.15&#34; resolution allows us to probe structures in the core region at unprecedented scales. With NGC

G. V. Vlasov

An attempt is made to explain the 8-second periodicity of the 5th March 1979 soft gamma-ray repeater as a consequence of the elastic wave precession in the rigid crust of the rotating neutron star.

F. Kienzle, P. Moskalik, D. Bersier, F. Pont

The light curves of the first overtone Pop. I Cepheids (s-Cepheids) show a discontinuity in their phi_21 vs. P diagram, near P=3.2 day. This feature, commonly attributed to the 2:1 resonance between the first and the fourth overtones (omega_4=2 omega_1), is not reproduced by the hydrodynamical models. With the goal of reexamining the resonance hypothesis, we

H. F. Chau, L. W. Siu, K. K. Yan

Suppose each site on a one-dimensional chain with periodic boundary condition may take on any one of the states $0,1,..., n-1$, can you find out the most frequently occurring state using cellular automaton? Here, we prove that while the above density classification task cannot be resolved by a single cellular automaton, this task can be performed efficiently

Gian F. Giudice, Markus A. Luty, Hitoshi Murayama, Riccardo Rattazzi

In models with dynamical supersymmetry breaking in the hidden sector, the gaugino masses in the observable sector have been believed to be extremely suppressed (below 1 keV), unless there is a gauge singlet in the hidden sector with specific couplings to the observable sector gauge multiplets. We point out that there is a pure supergravity contribution to ga

J. Corson, R. Mallozzi, J. Orenstein, J. N. Eckstein

Coherent time-domain spectroscopy is used to measure the screening and dissipation of high-frequency electromagnetic fields in a set of underdoped Bi_2Sr_2CaCu_2O_8+d thin films. The measurements provide direct evidence for a phase-fluctuation driven transition from the superconductor to normal state, with dynamics described well by the Berezinskii-Kosterlit

Claudio Chamon, Andreas W. W. Ludwig, Chetan Nayak

We develop a dynamical approach based on the Schwinger-Keldysh formalism to derive a field-theoretic description of disordered and interacting electron systems. We calculate within this formalism the perturbative RG equations for interacting electrons expanded around a diffusive Fermi liquid fixed point, as obtained originally by Finkelstein using replicas.

NA49 Collaboration

Net proton and negative hadron spectra for central \PbPb collisions at 158 GeV per nucleon at the CERN SPS were measured and compared to spectra from lighter systems. Net baryon distributions were derived from those of net protons, utilizing model calculations of isospin contributions as well as data and model calculations of strange baryon distributions. St

Barbara M. Terhal, David P. DiVincenzo

We address the question of how a quantum computer can be used to simulate experiments on quantum systems in thermal equilibrium. We present two approaches for the preparation of the equilibrium state on a quantum computer. For both approaches, we show that the output state of the algorithm, after long enough time, is the desired equilibrium. We present a num

David L. Meier

A model is presented in which both Fanaroff and Riley class I and II extragalactic jets are produced by magnetized accretion disk coronae in the ergospheres of rotating black holes. While the jets are produced in the accretion disk itself, the output power still is an increasing function of the black hole angular momentum. For high enough spin, the black hol

Thomas Schick

Suppose M is a compact manifold with boundary. Let N be a normal covering of M. Suppose (A,T) is an elliptic differential boundary value problem on M with lift (\tilde A,\tilde T) to N. Then the von Neumann dimension of kernel and cokernel of this lift are defined. The main result of this paper is: these numbers are finite, and their difference, by definitio

Thomas Curtright, Cosmas Zachos

Exact characteristic trajectories are specified for the time-propagating Wigner phase-space distribution function. They are especially simple---indeed, classical---for the quantized simple harmonic oscillator, which serves as the underpinning of the field theoretic Wigner functional formulation introduced. Scalar field theory is thus reformulated in terms of

David E. Rosenberg

Our universe has multiple examples of unexplained gravitational losses in black holes and neutron stars. The smallest black holes of about 4 solar masses means the maximum baryon density \rho \approx 10^{17} grams/cm^3. Any collapse of the universe will stop with a scale factor \approx 10^{13} cm. and radiation energy \approx 10 GeV. Due to higher squeezed c

James M. Cline, Michael Mostoslavsky, Geraldine Servant

Heckler has recently argued that the Hawking radiation emitted from microscopic black holes has sufficiently strong interactions above a certain critical temperature that it forms a photosphere, analogous to that of the sun. In this case, the visible radiation is much cooler than the central temperature at the Schwarzschild radius, in contrast to the naive e

Adam P. Szczepaniak, Anatoly Radyushkin

We calculate hard gluon contribution to the decay vertex that determines the heavy-to-light meson transition form factor at large recoil. It is found that resulting Sudakov suppression significantly decreases the soft, wave function dependent contribution to the form factor. Phenomenological implications of these findings are discussed.

S. Camalet, F. Julicher, J. Prost

We study a simple two-dimensional model for motion of an elastic filament subject to internally generated stresses and show that wave-like propagating shapes which can propel the filament can be induced by a self-organized mechanism via a dynamic instability. The resulting patterns of motion do not depend on the microscopic mechanism of the instability but o

Ph. Boucaud, J. P. Leroy, J. Micheli, O. Pene

We determine the three-loop coefficient of the beta function in the asymmetric momentum subtraction scheme in Landau gauge. This scheme is convenient for lattice studies of α_s, the running coupling constant of QCD. We present high statistics lattice results for α_s in the SU(3) Yang-Mills theory without quark, compare with the three-loop running and extract

Guy F. de Teramond

The fundamental chiral nature of the observed quarks and leptons and the emergence of the gauge group itself are most puzzling aspects of the standard model. Starting from general considerations of topological properties of gauge field configurations in higher space-time dimensions, it is shown that the existence of non-trivial structures in ten dimensions w

Francesco Vissani

A possible connection between the flavour structure of the charged fermions and the large $\nu_\mu-\nu_\tau$ mixing motivates an ansatz for the neutrino mass matrix with a dominant block. We distinguish between a general form and the specific forms of the ansatz, and concentrate on the cases of phenomenological interest. The general form can incorporate an o

Angel Ballesteros, Sergei M. Chumakov

Analytical expressions are given for the eigenvalues and eigenvectors of a Hamiltonian with su_q(2) dynamical symmetry. The relevance of such an operator in Quantum Optics is discussed. As an application, the ground state energy in the Dicke model is studied through su_q(2) perturbation theory.

Dirk Helbing, Martin Treiber

Recently, hysteretic transitions to `synchronized traffic&#39; with high values of both density and traffic flow were observed on German freeways [B. S. Kerner and H. Rehborn, Phys. Rev. Lett. 79, 4030 (1997)]. We propose a macroscopic traffic model based on a gas-kinetic approach that can explain this phase transition. The results suggest a general mechanis

H. E. van den Brom, J. M. van Ruitenbeek

The transmission of conductance modes in atom-size gold contacts is investigated by simultaneously measuring conductance and shot noise. The results give unambiguous evidence that the current in the smallest gold contacts is mostly carried by nearly fully transmitted modes. In particular, for a single-atom contact the contribution of additional modes is only

A. Bracco, P. H. Chavanis, A. Provenzale, E. A. Spiegel

In the problem of planetary formation one seeks a mechanism to gather small solid particles together into larger accumulations of solid matter. Here we describe a scenario in which turbulence mediates this process by aggregating particles into anticyclonic regions. If, as our simulations suggest, anticyclonic vortices form as long-lived coherent structures,

K. Horie, H. Miyazaki, I. Tsutsui, S. Tanimura

We study caustics in classical and quantum mechanics for systems with quadratic Lagrangians. We derive a closed form of the transition amplitude on caustics and discuss their physical implications in the Gaussian slit (gedanken-)experiment. Application to the quantum mechanical rotor casts doubt on the validilty of Jevicki&#39;s correspondence hypothesis whi

Christophe Chatelain, Bertrand Berche

The conformal covariance of correlation functions is checked in the second-order transition induced by random bonds in the two-dimensional 8-state Potts model. The decay of correlations is obtained {\it via} transfer matrix calculations in a cylinder geometry, and large-scale Monte Carlo simulations give access to the correlations and the profiles inside a s

Changhao Jin

We calculate the inclusive charmless semileptonic decay width of the B meson using a QCD-based approach. This approach is able to account for both dynamic and kinematic effects of nonperturbative QCD. The charmless semileptonic decay width is found to be enhanced by long-distance strong interactions by +(7\pm 5)% with respect to the free quark decay width. U

G. C. Gellas, T. R. Hemmert, C. N. Ktorides, G. I. Poulis

The three complex form factors entering the $Δ\to Nγ^\ast$ vertex are calculated to ${\cal O}(ε^3)$ in the framework of a chiral effective theory with explicit Δ(1232) degrees of freedom included. It is shown that the low q^2 behavior of the form factors is governed by $πN$, $πΔ$ loop effects. Predictions are given for the q^2-dependence of the three transit

S. Hino, S. Kumano

We discuss general formalism for the structure functions which can be investigated in the polarized Drell-Yan processes with spin-1/2 and spin-1 hadrons. To be specific, the formalism can be applied to the proton-deuteron Drell-Yan processes. Because of the spin-1 nature, there are new structure functions which cannot be studied in the proton-proton reaction

Vijay K. Narayanan, Andrew Gould

We show that the errors in the Hipparcos parallaxes towards the Pleiades and the Hyades open clusters are spatially correlated over angular scales of 2 to 3 deg, with an amplitude of up to 2 mas. This correlation is stronger than expected based on the analysis of the Hipparcos catalog. We predict the parallaxes of individual cluster members, pi_pm, from thei

G. N. Gibson, G. Dunne, K. J. Bergquist

We present a practical numerical technique for calculating tunneling ionization rates from arbitrary 1-D potential wells in the presence of a linear external potential by determining the widths of the resonances in the spectral density, rho(E), adiabatically connected to the field-free bound states. While this technique applies to more general external poten

William R. Wharton

Backward causation in which future events affect the past is formalized in a way consistent with Special Relativity and shown to restore locality to nonrelativistic quantum mechanics. It can explain the correlations of the EPR paradox without using hidden variables. It also restores time-symmetry to microphysics. Quantum Mechanics has the right properties to

M. Stepanov

This paper deals with the Autler - Townes doublet structure. Applied driving and probing laser fields can have arbitrary intensities. The explanation is given of the broadening of doublet components with the growth of probing field intensity, which was observed in experiment. The effects of Doppler averaging are discussed.

H. Witała, W. Glöckle, J. Golak, D. Hüber

The longitudinal and transversal asymmetries of the total $\vec{n}\vec{d}$ cross section are calculated. Four modern nucleon-nucleon interactions: AV18, CD Bonn, NijmI and NijmII, give different predictions for these observables. When the three-nucleon Hamiltonian is supplemented by the $2π$-exchange Tucson-Melbourne three-nucleon force (3NF), individually a

J. Geiss, E. Bratkovskaya, W. Cassing, C. Greiner

We study the production of $c \bar{c}$ pairs and dimuons from hard collisions in nuclear reactions within the covariant transport approach HSD. Adopting 6 mb for the $c \bar{c}$-baryon cross section the data on $J/Ψ$ suppression in p + A reactions are reproduced in line with calculations based on the Glauber model. Furthermore, using $J/Ψ$ absorption cross s

P. Thorngren Engblom, H. O. Meyer, J. T. Balewski, J. Doskow

With the aim to study spin dependence of pion production near threshold, an internal target facility and a forward detector have been installed in the Cooler synchrotron ring at IUCF. The detector system comprises scintillators and wire chambers. The target consists of a thin-walled open-ended storage cell into which polarized atomic hydrogen is injected. Us

Frederic J. Almgren, Igor Rivin

Suppose M_t is a smooth family of compact connected two dimensional submanifolds of Euclidean space E^3 without boundary varying isometrically in their induced Riemannian metrics. Then we show that the mean curvature integrals over M_t are constant. It is unknown whether there are nontrivial such bendings. The estimates also hold for periodic manifolds for w

Claus Hertling, Yuri Manin

We establish a new universal relation between the Lie bracket and $\circ$-multiplication of tangent fields on any Frobenius (super)manifold. We use this identity in order to introduce the notion of ``weak Frobenius manifold&#39;&#39; which does not involve metric as part of structure. As another application, we show that the powers of an Euler field generate

J. F. Feinstein, Herbert Kamowitz

When G is a region in the complex plane, compact composition operators on the uniform algebra of bounded analytic functions on G and the spectra of these operators were described by D. Swanton, Compact composition operators on B(D), Proc. Amer. Math. Soc. 56 (1976). In this short note we characterize all compact endomorphisms, not necessarily those induced b

I. V. Kanatchikov

A quantization of field theory based on the DeDonder-Weyl covariant Hamiltonian formulation is discussed. A hypercomplex extension of quantum mechanics, in which the space-time Clifford algebra replaces that of the complex numbers, appears as a result of quantization of Poisson brackets of differential forms put forward for the DeDonder-Weyl formulation earl

Konstantin G. Savvidy

I revisit the solution of Born-Infeld theory which corresponds to a 3-brane and anti-brane joined by a (fundamental) string. The global instability of this configuration makes possible the semiclassical tunneling into a wide, short tube which keeps expanding out, thus annihilating the brane . This tunneling is suppressed exponentially as $\exp(- S_{cl}/g)$.

Martin Schaden

The non-perturbative validity of covariant BRST-quantization of gauge theories on compact Euclidean space-time manifolds is reviewed. BRST-quantization is related to the construction of a Topological Quantum Field Theory (TQFT) of Witten type on the gauge group. The criterion for the non-perturbative validity of the quantization is that the partition functio

Michael G. Schmidt, Christian Schubert

We report on the status of the string-inspired world line path integral formalism, a recently developed powerful tool for the reorganisation of standard perturbative amplitudes in quantum field theory. The method is outlined and the present range of its applicability surveyed. The emphasis is on QED and QCD photon/gluon amplitudes, with a short discussion of

E. Mendel

After having developed a method that measures real time evolution of quantum systems at a finite temperature, we present here the simplest field theory where this scheme can be applied to, namely the 1+1 Ising model. We will compute the probability that if a given spin is up, some other spin will be up after a time $t$, the whole system being at temperature

F. Antonuccio, S. Pinsky, S. Tsujimaru

The Discrete Light-Cone Quantization (DLCQ) of a supersymmetric gauge theory in 1+1 dimensions is discussed, with particular attention given to the inclusion of the gauge zero mode. Interestingly, the notorious `zero-mode&#39; problem is now tractable because of special supersymmetric cancellations. In particular, we show that anomalous zero-mode contributio

R. Dijkgraaf

Fivebranes are non-perturbative objects in string theory that generalize two-dimensional conformal field theory and relate such diverse subjects as moduli spaces of vector bundles on surfaces, automorphic forms, elliptic genera, the geometry of Calabi-Yau threefolds, and generalized Kac-Moody algebras.

Leopoldo A. Pando Zayas

In Strominger&#39;s proposal for the computation of the statistical entropy of black holes based on the asymptotic symmetry analysis of Brown and Henneaux a fundamental role is played by the asymptotic conditions that the considered metric must satisfy at infinity. Here it is shown that $T$-duality does not preserve such conditions. This observation is used

Kim Maltman, Carl E. Wolfe

The isospin-breaking vector meson decay constants are determined from a QCD sum rule analysis of the vector current correlator $<O| T(V^3_μV^8_ν)| O>$, using a recently proposed implementation of the finite energy sum rule approach. The analysis employs the three-loop version of the OPE, and two different families of weight functions. It is shown that the re

H. Baer, F. E. Paige, S. D. Protopescu, X. Tata

ISAJET is a Monte Carlo program which simulates $pp, \bar pp$ and $e^+e^-$ interactions at high energies. This document summarizes the physics underlying the program and describes how to use it. New features of Version 7.40 include generation of $W+H$ and $Z+H$ events, non-minimal GMSB models, and use of the experimental $α_s(M_Z)$ by default.

A. Widom, J. Swain, Y. N. Srivastava

The real time exponential decay laws for meta-stable charged particles are shown to require radiative corrections. The methods employed are well known to be valid for radiatively correcting Breit-Wigner line shapes. Radiative corrections contribute substantially to precision life time measurements of muons and pions when initially stopped in condensed matter

Michael Melles, W. James Stirling

We present quantitative results on the cross section for $γ+ γ(J_z=0) \to b \bar{b}\to two b$-jets based on the recently achieved all orders resummation of large soft (Sudakov) and hard (non-Sudakov) double logarithms. The next-to-leading order QCD perturbative corrections are included exactly. We find that one needs to include at least four loops for the no

Kacper Zalewski

Correlations among identical bosons, which are familiar from statistical physics, play an increasingly important role in high energy multiple particle production processes. They provide information about the region, where the particles are produced and, if Einstein&#39;s condensation can be reached, they can lead to spectacular new phenomena.

P. Rehberg, J. Aichelin

The expansion and hadronization of a quark meson plasma is studied using an effective chiral interaction Lagrangian. The particles we consider are light as well as strange quarks, which can form pions, kaons and eta mesons via collision processes. The transport equations for the system are solved using a QMD type algorithm. We find that in chemical equilibri

A. D. Dolgov, S. H. Hansen

In the one-loop approximation we derive the equation of motion for a classical scalar field ϕ_c (t) with the back reaction of particle production included. Renormalization of mass and couplings of ϕ_c is done explicitly. The equation is non-local in time, but can easily be treated perturbatively or numerically. For the weak trilinear coupling of the external