March 1997 arXiv papers — page 10

George Jaroszkiewicz, Keith Norton

We discuss the principles to be used in the construction of discrete time classical and quantum mechanics as applied to point particle systems. In the classical theory this includes the concept of virtual path and the construction of system functions from classical Lagrangians, Cadzow's variational principle applied to the action sum, Maeda-Noether and L

Hitoshi Nishino, Ergin Sezgin

We describe the couplings of six-dimensional supergravity, which contain a self-dual tensor multiplet, to $n_T$ anti-self-dual tensor matter multiplets, $n_V$ vector multiplets and $n_H$ hypermultiplets. The scalar fields of the tensor multiplets form a coset $SO(n_T,1)/SO(n_T)$, while the scalars in the hypermultiplets form quaternionic Kähler symmetric spa

O. Abe, G. Aubrecht, K. Tanaka

Two dimensional QCD is quantized on the light front coordinate. We solve the Einstein-Schrödinger equation by the use of Tamm-Dancoff truncation and find that the simplest wavefunction produces the $M/g$ versus $m/g$ relation in agreement with other calculations, where $M$ and $m$ are the masses of the ground state and quarks, respectively.

James A. Feigenbaum, Peter G. O. Freund, Mircea Pigli

We show that a simple account of hadronic high energy total cross-sections and of the observed masses and flavor-gauge-like couplings of the familiar vector mesons is obtained in a hadronic string model suggested by QCD in the limit of a large number of colors. Our picture involves a Minkowski space which in addition to the well established continuous one ti

Frederick J. Gilman

We discuss the opportunities for experiments at the frontier of physics using K-meson beams after the current round of precision experiments looking for CP violation in the K meson decay amplitude and for flavor-changing neutral currents are completed and the B-factories at KEK and SLAC are running. We emphasize those experiments that will give complementary

Boris Kayser

Existing data on neutrino-electron scattering do not imply that neutrinos are not Majorana particles. The question of whether neutrinos are of Majorana or of Dirac character remains completely open.

H. González, S. R. Juárez W., P. Kielanowski, G. López Castro

Based on the hierarchy exhibited by quarks masses at low energies, we assume that Yukawa couplings of up and down quarks are related by $Y_u\propto Y_d^2$ at grand unification scales. This ansatz gives rise to a symmetrical CKM matrix at the grand unification (GU) scale. Using three specific models as illustrative examples for the evolution down to low energ

Andrzej Czarnecki, Kirill Melnikov

We present a complete $O(α_s^2)$ correction to the differential width of the inclusive semileptonic decay $b\to clν_l$ at the kinematical point of vanishing invariant mass of the leptons, $q^2=0$. Together with the recently computed $O(α_s^2)$ correction at the upper boundary of the lepton invariant mass spectrum, this new information permits an estimate of

J. Kubo, M. Mondragon, G. Zoupanos

Gauge-Yukawa Unification (GYU) is a renormalization group invariant functional relation among gauge and Yukawa couplings which holds beyond the unification point in Grand Unified Theories (GUTs). We present here various models where GYU is obtained by requiring the principles of finiteness and reduction of couplings. We examine the consequences of these requ

M. A. Halasz, A. D. Jackson, J. J. M. Verbaarschot

The presence of a chemical potential completely changes the analytical structure of the QCD partition function. In particular, the eigenvalues of the Dirac operator are distributed over a finite area in the complex plane, whereas the zeros of the partition function in the complex mass plane remain on a curve. In this paper we study the effects of the fermion

Andreas Koutras, Marc Mars

The general solution for non-rotating perfect-fluid spacetimes admitting one Killing vector and two conformal (non-isometric) Killing vectors spanning an abelian three-dimensional conformal algebra (C_3) acting on spacelike hypersurfaces is presented. It is of Petrov type D; some properties of the family such as matter contents are given. This family turns o

Michael Kapovich, John Millson

We prove that for any affine variety S defined over Q there exist Shephard and Artin groups G such that a Zariski open subset U of S is biregular isomorphic to a Zariski open subset of the character variety Hom(G, PO(3))//PO(3). The subset U contains all real points of S . As an application we construct new examples of finitely-presented groups which are not

S. N. Evangelou, D. E. Katsanos

We study numerically the effect of on-site Hubbard interaction U between two electrons in the quasiperiodic Harper's equation. In the periodic chain limit by mapping the problem to that of one electron in two dimensions with a diagonal line of impurities of strength U we demonstrate a band of resonance two particle pairing states starting from E=U. In th

J. Maucourt, D. R. Grempel

We study the two-dimensional XY model with quenched random phases by Monte Carlo simulation and finite-size scaling analysis. We determine the phase diagram of the model and study its critical behavior as a function of disorder and temperature. If the strength of the randomness is less than a critical value, $σ_{c}$, the system has a Kosterlitz-Thouless (KT)

Tapash Chakraborty, P. Pietiläinen, R. Shankar

The spin polarization versus temperature at or near a fully filled lowest Landau level is explored for finite-size systems in a periodic rectangular geometry. Our results at $ν=1$ which also include the finite-thickness correction are in good agreement with the experimental results. We also find that the interacting electron system results are in complete ag

G. E. Volovik, N. B. Kopnin

In a recent Letter Simon and Lee suggested a scaling law for thermodynamic and kinetic properties of superconductors with lines of gap nodes. However their crossover parameter between the bulk dominated regime and the vortex dominated regime is different from that found in our paper (N.B. Kopnin and G.E. Volovik, JETP Lett., {\bf 64}, 690 (1996); see also co

G. Casati, F. M. Izrailev, V. V. Sokolov

In a recent Letter [Phys.Rev.Lett., 77,4536 (1996), chao-dyn/9609014] Altland and Zirnbauer claim that they rigorously proved the complete analogy between a (classically chaotic) dynamical system and disordered (random) solids. The purpose of this Comment is to show that, in fact, their theory fails to take into account dynamical features which go beyond sta

K. Schoenhammer, C. Woehler

The exact nonequilibrium time evolution of the momentum distribution for a finite many particle system in one dimension with a linear energy dispersion coupled to optical phonons is presented. For distinguishable particles the influence function of the phonon bath can be evaluated also for a finite particle density in the thermodynamic limit. In the case of

M. Mostovoy, D. Khomskii

We study the (spin-)Peierls transition in quasi-one-dimensional disordered systems, treating the lattice classically. The role of kinks, induced thermally and by disorder, is emphasized. For weak interchain interaction the kinks destroy the coherence between different chains at a temperature significantly lower than the mean-field Peierls transition temperat

Maxim Mostovoy, Marc Thilo Figge, Jasper Knoester

We show that weak off-diagonal disorder in degenerate ground state conjugated polymers results in a finite density of randomly positioned kinks (solitons and antisolitons) in the lattice dimerization. For realistic values of the disorder, these kinks should clearly show up in the optical and magnetic properties.

Hyun Sik Noh, Sang Koo You, Chul Koo Kim

A finite temperature many-particle theory of condensed matter systems is formulated using the functional Schroedinger picture. Using the interacting electron gas as a model system, we solve the equation of motion for the density matrix variationally with a Gaussian type trial density matrix. We show that the present formalism yields the finite temperature Ha

Yong-Jihn Kim, K. J. Chang

We present some of the recent theoretical studies on the impurity effects in conventional superconductors, such as magnetic and ordinary impurity effects in dirty and weak localization limits, and describe successfully unexplained experimental results. We find that the critical sheet resistance for the suppression of superconductivity in thin films depends o

Eric Woods, Abraham Loeb

We use the existing catalog of Damped Lyman-Alpha (DLA) systems to place constraints on the amount of evolution in the baryonic content of galaxies and on the value of the cosmological constant. The density of cold gas at redshifts z=3+-1 is obtained from the mean HI column density of DLAs per cosmological path length. This path length per unit redshift is i

Michael Isenberg, D. Q. Lamb, John C. L. Wang

We use a Monte Carlo radiative transfer code to examine the dependence of the properties of cyclotron resonant scattering lines on the spatial geometry and the optical depth of the line-forming region. We focus most of our attention on a line-forming region that is a plane-parallel slab. We also consider a cylindrical line-forming region. In both cases, the

Slavek M. Rucinski

EUVE satellite spectroscopic observations (SW, MW and LW bands covering 80 - 160, 170 - 350 and 450 A with resolutions 0.5, 1 and 2 A) and photometric observations (Deep Sky Survey, broad-band 70 - 140 A) have been obtained for two contact, 44i Boo B and VW Cep, and one detached, ER Vul, close binary stars. All three systems have orbital periods shorter than

R. Coziol, T. Contini, E. Davoust, S. Considère

The metallicities derived from spectroscopic observations of a sample of Starburst Nucleus Galaxies (SBNGs) are compared to those of several other types of galaxies (normal giant galaxies, Irregular and HII galaxies) drawn from the literature. The SBNGs are deficient in metals with respect to normal galaxies of same morphological type, suggesting that - SBNG

Jongsoo Kim, Seung Soo Hong, Dongsu Ryu

A linear stability analysis has been done to a magnetized disk under a linear gravity. We have reduced the linearized perturbation equations to a second-order differential equation which resembles the Schrödinger equation with the potential of a harmonic oscillator. Depending on the signs of energy and potential terms, eigensolutions can be classified into `

N. Benitez, E. Martinez-Gonzalez, J. M. Martin-Mirones

K-band imaging of a sample of 21 radiogalaxies with z \sim 1.5 reveals the existence of a statistical association of foreground galaxies with the positions of the radiosources. The excess is detected within a 1' radius at a high significance level (>99.8%). K-band light is a good tracer of stellar mass, so this result indicates the existence of an associ

M. Boer, C. Motch, J. Greiner, W. Voges

We report on observations of the 1978, November 19 Gamma-Ray Burst source, performed with the ROSAT X-ray HRI experiment. Two sources were detected, one of which is possibly variable. The latter source is identical to the source discovered in 1981 by the EINSTEIN satellite, and recently detected by ASCA. The precise localization of these sources is given, an

M. Boettcher, R. Schlickeiser

We present the first completely analytical computation of the full differential γ-γpair production rate from compact radiation fields, exact to 2nd order QED, and use this result to investigate the validity of previously known approximations.

D. W. Sciama

We here update the derivation of precise values for the Hubble constant H_0, the age t_0 and the density parameter Omega*h^2 of the universe in the decaying neutrino theory for the ionisation of the interstellar medium (Sciama 1990 a, 1993). Using recent measurements of the temperature of the cosmic microwave background, of the abundances of D, He^4 and Li^7

B. M. Poggianti, G. Barbaro

The behaviour of the 4000 Angstrom break index and of the equivalent width of the main Balmer lines is investigated a) for a single star as a function of effective temperature, gravity and metallicity and b) for a single stellar population as a function of age and metallicity. Consequences for the interpretation of integrated spectra are presented.

Robert E. Lopez, Michael S. Turner, Geza Gyuk

We have calculated the small effect of finite nucleon mass on the weak-interaction rates that interconvert protons and neutrons in the early Universe. We have modified the standard code for primordial nucleosynthesis to include these corrections and find a small, systematic increase in the 4He yield, $\delta Y / Y \simeq (0.47 - 0.50)% $, depending slightly

Andrew Kresch

We describe interdependencies among the quantum cohomology associativity relations. We strengthen the first reconstruction theorem of Kontsevich and Manin by identifying a subcollection of the associativity relations which implies the full system of WDVV equations. This provides a tool for identifying non-geometric solutions to WDVV.

J. Kalinowski, R. Rueckl, H. Spiesberger, P. M. Zerwas

In reference to the recently observed high Q^2, large x events in deep-inelastic positron-proton scattering at HERA, various leptoquark and supersymmetric scenarios are discussed. We study the impact of virtual leptoquark or R-parity breaking squark exchange as well as generic contact interaction on the production of quark-antiquark pairs in $e^+e^-$ annihil

J. Blümlein

A summary is given on the experimental bounds for the couplings and masses of scalar and vector leptoquarks associated to the first fermion generation. We investigate to which extent an interpretation of the recently reported excess of events in the large $x$ and $Q^2$ range at HERA in terms of single leptoquark production is compatible with other experiment

Andrea Brignole, Ferruccio Feruglio, Fabio Zwirner

We discuss models where N=1 global supersymmetry is spontaneously broken, at the classical level, in the presence of non-anomalous gauge interactions. We take such models as effective theories, valid up to some suitable scale and arising from supergravity models with a light gravitino, and therefore we allow them to contain non-renormalizable interactions. F

Daniel Schaerer, Werner Schmutz, Michel Grenon

We report parallax measurements by the HIPPARCOS satellite of zeta Puppis and gamma^2 Velorum. The distance of zeta Pup is d=429 (+120/ -77) pc, in agreement with the commonly adopted value to Vela OB2. However, a significantly smaller distance is found for the gamma^2 Vel system: d=258 (+41/-31) pc. The total mass of gamma^2 Vel derived from its parallax, t

F. G. Padilla, F. Ritort

We revisit the hard-spheres lattice gas model in the spherical approximation proposed by Lebowitz and Percus (J. L. Lebowitz, J. K. Percus, Phys. Rev.{\ 144} (1966) 251). Although no disorder is present in the model, we find that the short-range dynamical restrictions in the model induce glassy behavior. We examine the off-equilibrium Langevin dynamics of th

B. Enriquez, G. Felder

We construct an algebra morphism from the elliptic quantum group $E_{τ,η}(sl_2)$ to a certain elliptic version of the ``quantum groups in higher genus'' studied by V. Rubtsov and the first author. This provides an embedding of $E_{τ,η}(sl_2)$ in an algebra ``with central extension''. In particular we construct $L^{\pm}$-operators obeying a dy

Alexios P. Polychronakos

A unitary matrix model is proposed as the large-N matrix formulation of M theory on flat space with toroidal topology. The model reproduces the motion of elementary D-particles on the compact space, and admits membrane states with nonzero wrapping around nontrivial 2-tori even at finite N.

Luis Alvarez-Gaume, Marcos Marino, Frederic Zamora

We present a general analysis of all the possible soft breakings of N=2 supersymmetric QCD, preserving the analytic properties of the Seiberg-Witten solutions for the SU(2) group with Nf=1, 2, 3 hypermultiplets. We obtain all the couplings of the spurion fields in terms of properties of the Seiberg-Witten periods, which we express in terms of elementary elli

Lars Ernström, Gary Kennedy

We construct an associative ring which is a deformation of the quantum cohomology ring of the projective plane. Just as the quantum cohomology encodes the incidence characteristic numbers of rational plane curves, the contact cohomology encodes the tangency characteristic numbers.

H. Dreiner, P. Morawitz

We discuss the recently observed excess of high Q2 neutral current deep inelastic scattering events at HERA in the light of supersymmetry with broken R-parity. We find more than one possible solution. We consider the possibilities for testing these hypotheses at HERA, the TEVATRON and at LEP. One lepton-number violating operator can account for both the HERA

Jonathan M. Evans, Jens Ole Madsen

An analysis is given of the structure of a general two-dimensional Toda field theory involving bosons and fermions which is defined in terms of a set of simple roots for a Lie superalgebra. It is shown that a simple root system for a superalgebra has two natural bosonic root systems associated with it which can be found very simply using Dynkin diagrams; the

J. Leon, A. V. Mikhailov

Stimulated Raman scattering of a laser pump pulse seeded by a Stokes pulse generically leaves a two-level medium initially at rest in an excited state constituted of static solitons and radiation. The soliton birth manifests as sudden very large variations of the phase of the output pump pulse. This is proved by building the IST solution of SRS on the semi-l

M. A. Manna, V. Merle

We study solitary-wave and kink-wave solutions of a modified Boussinesq equation through a multiple-time reductive perturbation method. We use appropriated modified Korteweg-de Vries hierarchies to eliminate secular producing terms in each order of the perturbative scheme. We show that the multiple-time variables needed to obtain a regular perturbative serie

Markus Grassl, Thomas Beth

A method to combine two quantum error-correcting codes is presented. Even when starting with additive codes, the resulting code might be non-additive. Furthermore, the notion of the erasure space is introduced which gives a full characterisation of the erasure-correcting capabilities of the codes. For the special case that the two codes are unitary images of

Mark Burgess, Margaret Carrington, Gabor Kunstatter

We describe an effective field theory for atomic lasers which reduces to the Jaynes-Cummings model in the non-relativistic, single mode limit. Our action describes a multi-mode system, with general polarizations and Lorentz invariance and can therefore be used in all contexts from the astrophysical to the laboratory. We show how to compute the effective acti

Eric L. Bolda, Sze M. Tan, Dan F. Walls

We propose a scheme to reconstruct the state of a two-mode Bose-Einstein condensate, with a given total number of atoms, using an atom interferometer that requires beam splitter, phase shift and non-ideal atom counting operations. The density matrix in the number-state basis can be computed directly from the probabilities of different counts for various phas

Moshe Flato, Giuseppe Dito, Daniel Sternheimer

We start with an overview of the "generalized Hamiltonian dynamics" introduced in 1973 by Y. Nambu, its motivations, mathematical background and subsequent developments -- all of it on the classical level. This includes the notion (not present in Nambu's work) of a generalization of the Jacobi identity called Fundamental Identity. We then briefly

Ken-ichi Matsuba, Kazuhiro Nozaki

A proper formulation in the perturbative renormalization group method is presented to deduce amplitude equations. The formulation makes it possible not only avoiding a serious difficulty in the previous reduction to amplitude equations by eliminating all of the secular terms but also consistent derivation of higher-order correction to amplitude equations.

A. Trasobares, A. Polls, A. Ramos, H. Müther

The relativistic structure of the self-energy of a nucleon in nuclear matter is investigated including the imaginary and real components which arise from the terms of first and second order in the NN interaction. A parameterized form of Brueckner $G$ matrix is used for the NN interaction. The effects of the terms beyond the DBHF approximation on quasiparticl

Justus H. Koch, Hubertus R. Mall, Stefan Lenz

We investigate the use of stochastic methods for zero energy quantum scattering based on a path integral approach. With the application to the scattering of a projectile from a nuclear many body target in mind, we use the potential scattering of a particle as a test for the accuracy and efficiency of several methods. To be able to deal with complex potential

K. Pomorski, P. Ring, G. A. Lalazissis, A. Baran

The separation energies of neutrons and protons, binding energies, mean square charge radii, electric quadrupole moments and deformation parameters of the proton and neutron distributions are evaluated for $β$ stable even-even nuclei with $16 \leq A \leq 256$. We compare the theoretical estimates obtained within the Hartree-Fock plus BCS model with a few set

Jacques Thévenaz

We determine all maximal subgroups of the direct product $\sc G^n$ of $\sc n$ copies of a group~$\sc G$. If $\sc G$ is finite, we show that the number of maximal subgroups of~$\sc G^n$ is a quadratic function of~$\sc n$ if $\sc G$ is perfect, but grows exponentially otherwise. We~deduce a theorem of Wiegold about the growth behaviour of the number of generat

Ian I. Kogan, Richard J. Szabo

We examine the relations between observables in two- and three-dimensional quantum gravity by studying the coupling of topologically massive gravity to matter fields in non-trivial representations of the three-dimensional Lorentz group. We show that the gravitational renormalization of spin up to one-loop order in these theories reproduces the leading orders

Masako Asano

We construct stringy cosmic string solutions corresponding to compactifications of F-theory on several elliptic Calabi-Yau manifolds by solving the equations of motion of low energy effective action of ten dimensional type IIB superstring theory. Existence of such solutions supports the compactifications of F-theory.

Ioannis P. Zois

We use the homological algebra context to give a more rigorous proof of Polyakov's basic variational formula for loop spaces.

Michael A. Doncheski, Stephen Godfrey

We investigate the discovery potential for first generation leptoquarks at the LEP200 $e^+e^-$ collider. We consider direct leptoquark searches using single leptoquark production via resolved photon contributions which offers a much higher kinematic limit than the more commonly considered leptoquark pair production process. Depending on the coupling strength

J. A. M. Vermaseren, S. A. Larin, T. van Ritbergen

We present the analytical calculation of the four-loop quark mass anomalous dimension in Quantum Chromodynamics within the minimal subtraction scheme. On the basis of this result we find that the so-called invariant quark mass is a very good reference mass for the accurate evolution of the running MS-bar quark mass in phenomenological applications. We also o

R. Fiore, L. L Jenkovszky, F. Paccanoni, E. Predazzi

The large rapidity gap events from HERA are analyzed within a model containing a pomeron and an $f$-reggeon contribution. The choice for the pomeron contribution is based on the Donnachie-Landshoff model. The dependence of the "effective intercept" of the pomeron on the momentum fraction $β$ and on its Bjorken variable $ξ$ is calculated.

S. Loh, C. Greiner, M. H. Thoma, U. Mosel

A dynamical model of confinement based on a microscopic transport description of the Friedberg-Lee model is extended to explicit color degrees of freedom. The string tension is reproduced by an adiabatic string formation from the nucleon ground state. As a particular application, we address the question of how a charmonium state might be dissociated by the s

G. J. Gounaris, D. T. Papadamou, F. M. Renard

We show that in e-e+ colliders at energies above the Z-peak, the process e-e+ to b b(bar) becomes very sensitive to the presence of residual New Physics (NP) effects described by the dim=6 SU(3)*SU(2)*U(1) gauge invariant operators O(qW), O(qB) and O(bB). This observation should be combined with the already known great sensitivity of the light fermion produc

Bernd A. Kniehl, Gustav Kramer

We study J/psi photoproduction via fragmentation at next-to-leading order in the QCD-improved parton model, using the nonrelativistic factorization formalism proposed by Bodwin, Braaten, and Lepage. We consider direct and resolved photoproduction of prompt J/psi mesons and chi_{cJ} mesons radiatively decaying to J/psi+gamma, taking into account the formation

T. Giamarchi, P. Le Doussal

We study periodic lattices, such as vortex lattices in type II superconductors in a random pinning potential. For the static case we review the prediction that the phase diagram of such systems consists of a topologically ordered Bragg glass phase, with quasi long range translational order, at low fields. This Bragg glass phase undergoes a transition at high

Lilia Meza-Montes, Sergio E. Ulloa

The problem of two interacting particles moving in a d-dimensional billiard is considered here. A suitable coordinate transformation leads to the problem of a particle in an unconventional hyperbilliard. A dynamical map can be readily constructed for this general system, which greatly simplifies calculations. As a particular example, we consider two identica

N. Chernov, Joel L. Lebowitz

We investigate stationary nonequilibrium states of systems of particles moving according to Hamiltonian dynamics with specified potentials. The systems are driven away from equilibrium by Maxwell demon ``reflection rules'' at the walls. These deterministic rules conserve energy but not phase space volume, and the resulting global dynamics may or may

M. E. J. Newman, G. T. Barkema

The repton model is a simple model of the "reptation" motion by which DNA diffuses through a gel during electrophoresis. In this paper we show that the model can be mapped onto a system consisting of two types of particles with hard-sphere interactions diffusing on a one-dimensional lattice. Using this mapping we formulate an efficient Monte Carlo al

V. Gorentsveig, P. Fratzl, J. L. Lebowitz

We study phase segregation in a model alloy undergoing both ordering and decomposition, using computer simulations of Kawasaki exchange dynamics on a square lattice. Following a quench into the miscibility gap we observe an early stage in which ordering develops while the composition remains almost uniform. Then decomposition starts with segregation into ord

M. Krech

If two ore more bodies are immersed in a critical fluid critical fluctuations of the order parameter generate long ranged forces between these bodies. Due to the underlying mechanism these forces are close analogues of the well known Casimir forces in electromagnetism. For the special case of a binary liquid mixture near its critical demixing transition conf

Thomas Christen

We show that in a macroscopic perfect insulator, charge injection at a field-enhancing defect is associated with an instability of the insulating state or with bistability of the insulating and the charged state. The effect of a nonlinear carrier mobility is emphasized. The formation of the charged state is governed by two different processes with clearly se

A. Barrat, S. Franz, G. Parisi

The correlations of the free-energy landscape of mean-field spin glasses at different temperatures are investigated, concentrating on models with a first order freezing transition. Using a ``potential function'' we follow the metastable states of the model in temperature, and discuss the possibility of level crossing (which we do not find) and multif

M. R. Cimberle, C. Ferdeghini, E. Giannini, D. Marré

We present paraconductivity (AL) measurements in three different high temperature superconductors: a melt textured $YBa_2Cu_3O_7$ sample, a $Bi_2Sr_2CaCu_2O_8$ epitaxial thin film and a highly textured $Bi_2Sr_2Ca_2Cu_3O_{10}$ tape. The crossovers between different temperature regimes in excess conductivity have been analysed. The Lawrence-Doniach (LD) cross

Carla Goldman, Robson Francisco de Souza

In view of the critical behavior exhibited by a statistical model describing a one dimensional crystal containing isotopic impurities and the fact that for impurity mass parameter 3 times the host mass the critical temperature can attain very high values, we suggest that the mosaic structure displayed by certain nucleic acids (DNA) of eukaryotic organisms mi

G. Vattay, J. Cserti, G. Palla, G. Szálka

In pseudo integrable systems diffractive scattering caused by wedges and impurities can be described within the framework of Geometric Theory of Diffraction (GDT) in a way similar to the one used in the Periodic Orbit Theory of Diffraction (POTD). We derive formulas expressing the reflection and transition matrix elements for one and many diffractive points

J. Feinberg, A. Zee

We consider random non-hermitean matrices in the large $N$ limit. The power of analytic function theory cannot be brought to bear directly to analyze non-hermitean random matrices, in contrast to hermitean random matrices. To overcome this difficulty, we show that associated to each ensemble of non-hermitean matrices there is an auxiliary ensemble of random

P. N. Best, M. S. Longair, H. J. A. Röttgering

We report the detection of a strong jet-cloud interaction at a distance of 120 kpc from the nucleus of the radio galaxy 3C34, which has redshift z=0.69. Hubble Space Telescope images of the radio galaxy show a long narrow region of blue emission orientated along the radio axis and directed towards a radio hotspot. The William Herschel Telescope has been used

A. Borione, M. A. Catanese, M. C. Chantell, C. E. Covault

We describe a new search for diffuse ultrahigh energy gamma-ray emission associated with molecular clouds in the galactic disk. The Chicago Air Shower Array (CASA), operating in coincidence with the Michigan muon array (MIA), has recorded over 2.2 x 10^{9} air showers from April 4, 1990 to October 7, 1995. We search for gamma rays based upon the muon content

S. C. Trager, S. M. Faber, A. Dressler, A. Oemler

We report the discovery of four high-redshift objects (3.3 < z < 4) observed behind the rich cluster CL0939+4713 (Abell 851). One object (DG 433) has a redshift of z=3.3453; the other three objects have redshifts of z\approx 4: A0 at z=3.9819, DG 353 and P1/P2 at z=3.9822. It is possible that all four objects are being lensed in some way by the cluster, DG 4

James Rhys Murray

In this paper we briefly discuss the ways in which angular momentum transport is included in simulations of non-self-gravitating accretion disks, concentrating on disks in close binaries. Numerical approaches fall in two basic categories; particle based Lagrangian schemes, and grid based Eulerian techniques. Underlying the choice of numerical technique are a

C. S. Kochanek

We develop a statistical method for using multicolor photometry to determine distances using Cepheid variables including the effects of temperature, extinction, and metallicity and apply it to UBVRIJHK photometry of 694 Cepheids in 17 galaxies. We derive homogeneous distance, extinction and uncertainty estimates for four models, starting from the standard ex

Robert J. Brunner, Andrew J. Connolly, Alexander S. Szalay, Matthew A. Bershady

We present the initial results from a deep, multi-band photometric survey of selected high Galactic latitude redshift fields. Previous work using the photographic data of Koo and Kron demonstrated that the distribution of galaxies in the multi-dimensional flux space U B R I is nearly planar. The position of a galaxy within this plane is determined by its red

Andreas Burkert

The rotation curves of dark matter dominated dwarf galaxies are analysed. The observations show that dark matter halos represent a one-parameter family with self similar density profiles. The global halo parameters, like total mass and scale length are coupled by simple scaling relations. The inner halo regions resemble non-singular, isothermal spheres with

Guenter Sigl

The formation of neutrino spectra in a supernova depends crucially on strength and inelasticity of weak interactions in hot nuclear matter. Neutrino interactions with nonrelativistic nucleons are mainly governed by the dynamical structure function for the nucleon spin density which describes its fluctuations. It has recently been shown that these fluctuation

P. N. Best, M. S. Longair, H. J. A. Röttgering

We investigate the old stellar populations of the 3CR radio galaxies at redshift z ~ 1, using observations made with the Hubble Space Telescope and the United Kingdom InfraRed Telescope. At radii r < 35 kpc, the infrared radial intensity profiles of the galaxies follow de Vaucouleurs&#39; law, whilst at larger radii the galaxies show an excess of emission si

Lyman A. Page

The cosmic microwave background (CMB) comprises the oldest photons in the universe and is arguably our most direct cosmological observable. All precise and accurate measurements of its attributes serve to distinguish between cosmological models. Detector technology and observing techniques have advanced to the point where fluctuations in the CMB of order a f

W. Landsman, J. Aparicio, P. Bergeron, R. Di Stefano

We have obtained spectra of the yellow giant S1040 in the open cluster M67 using the Goddard High-Resolution Spectrograph (GHRS) and the Faint Object Spectrograph on the Hubble Space Telescope. S1040 is a single-lined spectroscopic binary with a 42.8d period that occupies a &#34;red straggler&#34; position in the M67 color-magnitude diagram (CMD), 0.2 mag bl

Antonio Campillo, Janusz Grabowski, Gerd Müller

Normal affine algebraic varieties in characteristic 0 are uniquely determined (up to isomorphism) by the Lie algebra of derivations of their coordinate ring. This is not true without the hypothesis of normality. But, we show that (in general, non-normal) toric varieties defined by simplicial affine semigroups are uniquely determined by their Lie algebra if t

Viktor L. Ginzburg

A smooth counterexample to the Hamiltonian Seifert conjecture for six-dimensional symplectic manifolds is found. In particular, we construct a smooth proper function on the symplectic 2n-dimensional vector space, 2n > 4, such that one of its non-singular level sets carries no periodic orbits of the Hamiltonian flow. The function can be taken to be C^0-close

Andrzej Czarnecki, Kirill Melnikov

We present analytical results for the $O(α_s ^2)$ contributions to the functions $η_A$ and $η_V$ which parameterize QCD corrections to semileptonic $b \to c$ transitions at zero recoil. Previously obtained approximate results are confirmed. The methods of computing the relevant two-loop diagrams with two mass scales are discussed in some detail.

Chongying Dong, Haisheng Li, Geoffrey Mason

The goal of the present paper is to provide a mathematically rigorous foundation to certain aspects of rational orbifold conformal field theory, in other words the theory of rational vertex operator algebras and their automorphisms. Under a certain finiteness condition on a rational vertex operator algebra V which holds in all known examples, we determine th

Arvind Rajaraman

For minimally coupled scalars at low frequencies, the D-brane model has the same spectrum of radiation as the Hawking radiation from a black hole. We perform a similar comparison for another type of scalar which we call an intermediate scalar. In this case, we find that there is a discrepancy between the D-brane model and the black hole even for very low fre

J. N. Ginocchio, A. Leviatan

Sum rules for the total- and scissors-mode M1 strength in odd-A nuclei are derived within the single-j interacting boson-fermion model. We discuss the physical content and geometric interpretation of these sum rules and apply them to ^{167}Er and ^{161}Dy. We find consistency with the former measurements but not with the latter.

G. Altarelli, J. Ellis, S. Lola, G. F. Giudice

We explore interpretations of the anomaly observed by H1 and ZEUS at HERA in deep-inelastic e^+ p scattering at very large Q^2. We discuss the possibilities of new effective interactions and the production of a narrow state of mass 200 GeV with leptoquark couplings. We compare these models with the measured Q^2 distributions: for the contact terms, constrain

Alexander Chervov

We prove the formula for the traces of certain class of operators in bosonic and fermionic Fock spaces. Vertex operators belong to this class. Traces of vertex operators can be used for calculation of correlation functions and formfactors of integrable models (XXZ, Sine-Gordon, etc.), that is why we are interested in this problem. Also we show that Fredholm&

Jean-Luc Brylinski, Philip Foth

We consider the moduli space MN of flat unitary connections on an open Kaehler manifold U (complement of a divisor with normal crossings) with restrictions on their monodromy transformations. Using intersection and L2 cohomologies with degenerating coefficients we construct a natural symplectic form F on MN. When U is quasi-projective we prove that F is actu

Y. S. Kim

Paul A. M. Dirac was a great physicist. Wigner used to call him ``my famous brother-in-law&#39;&#39;. How did they become brothers-in-law? Did these two great physicists have the same view toward physics?

Stefan Bernard, Dirk H. Rischke, Joachim A. Maruhn, Walter Greiner

Pion and kaon correlations in relativistic nuclear collisions are studied in the framework of boost-invariant, cylindrically symmetric hydrodynamics. It is investigated how the inverse widths of the two-particle correlation functions in out- and side-direction depend on the average transverse momentum of the particle pair, the initial energy density, and the

I. P. Zois

We present a starting point for the search for a Lagrangian density for M-Theory using characteristic classes for flat foliations of bundles.