December 1996 arXiv papers — page 9

Robert Baur, Res Urech

The effective chiral Lagrangian of the strong and electromagnetic interactions of the pseudoscalar mesons at low energies depends on a set of low energy constants. We determine the contributions to the electromagnetic coupling constants at order $O(e^2 p^2)$, which arise from resonances within a photon loop. We give some implications of our results, in parti

N. Ishibashi, H. Kawai, Y. Kitazawa, A. Tsuchiya

A matrix model which has the manifest ten-dimensional N=2 super Poincare invariance is proposed. Interactions between BPS-saturated states are analyzed to show that massless spectrum is the same as that of type IIB string theory. It is conjectured that the large-N reduced model of ten-dimensional super Yang-Mills theory can be regarded as a constructive defi

J. Stutzki, U. U. Graf, S. Haas, C. E. Honingh

We report the first extragalactic detection of the neutral carbon [CI] 3P2-3P1 fine structure line at 809 GHz. The line was observed towards M82 simultaneously with the 3P1-3P0 line at 492 GHz, providing a precise measurement of the J=2-1/J=1-0 integrated line ratio of 0.96 (on a [K km s^-1] -scale). This ratio constrains the [CI] emitting gas to have a temp

Ryuji Kemmoku

Inspired by the fact that the Moyal quantization is related with nonlocal operation, I define a difference analogue of vector fields and rephrase quantum description on the phase space. Applying this prescription to the theory of the KP-hierarchy, I show that their integrability follows to the nature of their Wigner distribution. Furthermore the definition o

Joachim Kupsch

The role of superselection rules for the derivation of classical probability within quantum mechanics is investigated and examples of superselection rules induced by the environment are discussed.

Todd A. Brun, Stephen M. Barnett

Inserting a lossy dielectric into one arm of an interference experiment acts in many ways like a measurement. If two entangled photons are passed through the interferometer, a certain amount of information is gained about which path they took, and the interference pattern in a coincidence count measurement is suppressed. However, by inserting a second dielec

Markus J. Pflaum, Martin Schottenloher

In this article we propose a new and so-called holomorphic deformation scheme for locally convex algebras and Hopf algebras. Essentially we regard converging power series expansion of a deformed product on a locally convex algebra, thus giving the means to actually insert complex values for the deformation parameter. Moreover we establish a topological duali

Michitomo Nishizawa, Kimio Ueno

Two integral solutions of q-difference equations of the hypergeometric type with |q|=1 are constructed by using the double sine function. One is an integral of the Barnes type and the other is of the Euler type.

W. Cassing, Ye. S. Golubeva, A. S. Iljinov, L. A. Kondratyuk

The $ω$- and $ρ$-resonance production and their dileptonic decay in $π^- A$ reactions at GSI energies are calculated within the intranuclear cascade (INC) approach. The invariant mass distribution of the dilepton pair for each resonance is found to have two components which correspond to the decay of the resonances outside and inside the target nucleus. The

Bernard Pire, Ingo Sick

We review the presentations given in the Color Transparency parallel session held during the second ELFE workshop.

Serdar Kuyucak, Ka-Hae Kim, Takaharu Otsuka

We explore the possibility of shape transitions in proton-neutron systems driven by deformation differences between proton and neutron fluids. Within the framework of the proton-neutron interacting boson model, we show that such dynamic shape transitions cannot occur in well deformed nuclei but are a possibility in transitional nuclei. Likely candidates in t

Wolfram Koepf

In this note we solve a problem about the rational representablility of hupergeometric terms which represent hypergeometric sums. This problem was proposed by Koornwinder in [4].

Stephen Ryan

We show the nonequivalence of combinations of several natural geometric restrictions on trapezoid representations of trapezoid orders. Each of the properties unit parallelogram, unit trapezoid and proper parallelogram, unit trapezoid and parallelogram, unit trapezoid, proper parallelogram, proper trapezoid and parallelogram, proper trapezoid, parallelogram,

Anders Björner, Svante Linusson

Consider the question: Given integers $k<d<n$, does there exist a simple $d$-polytope with $n$ faces of dimension $k$? We show that there exist numbers $G(d,k)$ and $N(d,k)$ such that for $n> N(d,k)$ the answer is yes if and only if $n\equiv 0\quad \pmod {G(d,k)}$. Furthermore, a formula for $G(d,k)$ is given, showing that e.g. $G(d,k)=1$ if $k\ge \left\lflo

Anders Björner, Torsten Ekedahl

The enumeration of points on (or off) the union of some linear or affine subspaces over a finite field is dealt with in combinatorics via the characteristic polynomial and in algebraic geometry via the zeta function. We discuss the basic relations between these two points of view. Counting points is also related to the $\ell$-adic cohomology of the arrangeme

M. Kruczenski, L. E. Oxman

We obtain the internal degrees of freedom of the skyrmion (spin and isospin) within a manifestly Lorentz covariant quantization framework based on defining Green functions for skyrmions and then, the S-matrix via LSZ reduction. Our method follows Frohlich and Marchetti's definition of Euclidean soliton Green functions, supplemented with a careful treatment o

M. B. Green, M. Gutperle

The potential between two separated D-instantons at fixed (super) space-time points is obtained by a simple explicit integration over the `massive&#39; variables of the zero-dimensional reduction of ten-dimensional U(2) super Yang-Mills theory. This potential vanishes for asymptotically large separations, becoming significant at separations of around the ten

Michael R. Douglas

We discuss the origin of enhanced gauge symmetry in ALE (and K3) compactification of M theory, either defined as the strong coupling limit of the type IIa superstring, or as defined by Banks et al. In the D-brane formalism, wrapped membranes are D0 branes with twisted string boundary conditions, and appear on the same footing with the Kaluza-Klein excitation

Ashok Das, Sergio. A. Pernice

Higher dimensional supersymmetric quantum mechanics is studied. General properties of the two dimensional case are presented. For three spatial dimesions or higher, a spin structure is shown to arise naturally from the nonrelativistic supersymmetry algebra.

Ph. Droz-Vincent

Directly interacting particles are considered in the multitime formalism of predictive relativistic mechanics. When the equations of motion leave a phase-space volume invariant, it turns out that the phase average of any first integral, covariantly defined as a flux across a $7n$-dimensional surface, is conserved. The Hamiltonian case is discussed, a class o

Michael Goodband

We consider perturbations in the fields of the &#39;t Hooft-Polyakov monopole, dyon and point electric solutions. We find a series of bound modes where the fields are confined to the core of the respective solutions, and these are interpreted as bound states of a gauge boson with the respective solutions. We discuss the spectra of these bound states of the v

Ashok Das, Sergio A. Pernice

A new mechanism for symmetry breaking is proposed which naturally avoids the constraints following from the usual theorems of symmetry breaking. In the context of super-symmetry, for example, the breaking may be consistent with a vanishing vacuum energy. A 2+1 dimensional super-symmetric gauge field theory is explicitly shown to break super-symmetry through

Itzhak Bars, Costas Kounnas

We propose a new supersymmetry in field theory that generalizes standard supersymmetry and we construct field theoretic models that provide some of its representations. This symmetry combines a finite number of standard 4D supersymmetry multiplets into a single multiplet with a new type of Kaluza-Klein embedding in higher dimensions. We suggest that this mec

S. Leseduarte, August Romeo

We study the simultaneous influence of boundary conditions and external fields on quantum fluctuations by considering vacuum zero-point energies for quantum fields in the presence of a magnetic fluxon confined by a bag, circular and spherical for bosons and circular for fermions. The Casimir effect is calculated in a generalized cut-off regularization after

Joseph D. Lykken

These lectures give a self-contained introduction to supersymmetry from a modern perspective. Emphasis is placed on material essential to understanding duality. Topics include: central charges and BPS-saturated states, supersymmetric nonlinear sigma models, N=2 Yang-Mills theory, holomorphy and the N=2 Yang-Mills beta function, supersymmetry in 2, 6, 10, and

James M. Gelb, Waikwok Kwong, S. P. Rosen

We point out that the length scale associated with the MSW effect is the radius of the Earth. Therefore to verify matter enhancement of neutrino oscillations, it will be necessary to study neutrinos passing through the Earth. For the parameters of MSW solutions to the solar neutrino problem, the only detectable effects occur in a narrow band of energies from

J. Sucher

Helium was first isolated on Earth in 1895, by Sir William Ramsey. One hundred and one years later, it seems like a good time to review our current theoretical understanding of the helium atom. Helium has played an important role in the development of both quantum mechanics and of quantum field theory. The early history of helium is sketched. Various aspects

Martin C. Smith, Scott S. Willenbrock

The top quark decays more quickly than the strong-interaction time scale, $\lqcd^{-1}$, and might be expected to escape the effects of nonperturbative QCD. Nevertheless, the top-quark pole mass, like the mass of a stable heavy quark, is ambiguous by an amount proportional to $\lqcd$.

Jonathan L. Rosner

The currently favored model of CP violation is based on phases in the Cabibbo-Kobayashi-Maskawa (CKM) matrix describing the weak charge-changing couplings of quarks. The present status of parameters of this matrix is described. Tests of the theory, with particular emphasis on the study of B meson decays, are then noted. Some remarks are made regarding the po

A. L. Kataev, N. V. Krasnikov, A. A. Pivovarov

This is an erratum to the paper published in Nucl. Phys. B198(1982)508.

O. K. Kalashnikov

The Fermi excitations in hot and dense quark-gluon plasma are studied in the Feynman gauge using the temperature Green function technique. We find the four well-separated branches for the case $m=0$ and establish the additional splitting between them (the four different masses) when $m\ne 0$. The long wavelength limit of these excitations is found in the gen

Yoshio Koide, Hideo Fusaoka

On the basis of a seesaw-type mass matrix model $M_f\simeq m_L M_F^{-1} m_R$ for quarks and leptons $f$, analytical expressions of the masses and mixings of the fermions $f$ are investigated. Here, the matrices $m_L$ and $m_R$ are common to all $f$ (up- and down-; quarks and leptons), and the matrix $M_F$ characterizing the heavy fermion sector has the form

Ambar Ghosal, Anirban Kundu, Biswarup Mukhopadhyaya

Using the facts that in Gauge-Mediated Supersymmetry Breaking schemes, masses of the right and the left sfermions can differ widely, and the gravitino is the Lightest Supersymmetric Particle, we show that it is possible to obtain unambiguous signatures of such schemes in a high energy $e^+e^-$ collider if one looks at the asymmetries in the cross-sections fo

P. N. Burrows

The determination of alpha_s(M_Z^2) using O(alpha_s^2) calculations of hadronic event observables in e+e- annihilation is reviewed. The large scatter among alpha_s(M_Z^2) values determined from different observables may be interpreted as arising from the effect of uncalculated higher-order contributions. The application of `optimised&#39; perturbation theory

P. N. Burrows

Determinations of alpha_s are reviewed. Current results are limited to a precision of around 3-20%, largely by theoretical uncertainties. All measurements are consistent with a `world average&#39; value of 0.118 +- 0.005 and there is no evodence of any discrepancy between `low-Q^2&#39; and `high-Q^2&#39; results.

Marco Spaans

A set of algebraic equations for the topological properties of space-time is derived, and used to extend general relativity into the Planck domain. A unique basis set of three-dimensional prime manifolds is constructed which consists of $S^3$, $S^1\times S^2$, and $T^3$. The action of a loop algebra on these prime manifolds yields topological invariants whic

S. F. J. Chan, R. B. Mann

Conformally invariant scalar waves in black hole spacetimes which are asymptotically anti-de Sitter are investigated. We consider both the $(2+1)$-dimensional black hole and $(3+1)$-dimensional Schwarzschild-anti-de Sitter spacetime as backgrounds. Analytical and numerical methods show that the waves decay exponentially in the $(2+1)$ dimensional black hole

Joseph Katz, Dorit Lerer

The ``standard&#39;&#39; expressions for total energy, linear momentum and also angular momentum of asymptotically flat Bondi metrics at null infinity are also obtained from differential conservation laws on asymptotically flat backgrounds, derived from a quadratic Lagrangian density by methods currently used in classical field theory. It is thus a matter of

F. Belgiorno, S. Liberati

An analogy between the subtraction procedure in the Gibbons-Hawking Euclidean path integral approach to Horizon&#39;s Thermodynamics and the Casimir effect is shown. Then a conjecture about a possible Casimir nature of the Gibbons-Hawking subtraction is made in the framework of Sakharov&#39;s induced gravity. In this framework it appears that the degrees of

H. F. Fong, B. Keimer, D. L. Milius, I. A. Aksay

Polarized and unpolarized neutron scattering has been used to determine the effect of superconductivity on the magnetic excitation spectra of YBa_2 Cu_3 O_{6.5} (T_c = 52K) and YBa_2 Cu_3 O_{6.7} (T_c = 67K). Pronounced enhancements of the spectral weight centered around 25 meV and 33 meV, respectively, are observed below T_c in both crystals, compensated pr

Hiroaki Kusunose, Kazumasa Miyake

We investigate a problem about the competition between the hybridization and the Hund-rule coupling by applying the Wilson numerical renormalization-group method to the extended Kondo model where the impurity spin interacts via the Hund-rule coupling, with an extra spin which is isolated from the conduction electrons. It is shown that the Hund-rule coupling

Fabio Bernardini, Vincenzo Fiorentin, David Vanderbilt

The strain induced by lattice mismatch at the interface is responsible for the different value of the band discontinuities observed recently for the AlN/GaN (AlN on GaN) and the GaN/AlN (GaN on AlN) polar (0001) interface. We present a first-principles calculation of valence band offsets, interface dipoles, strain-induced piezoelectric fields, relaxed geomet

C. O&#39;Donovan, J. P. Carbotte

YBaCuO_7 is a trilayer material with a unit cell consisting of a CuO_2 bilayer with a CuO plane of chains in between. Starting with a model of isolated planes coupled through a transverse matrix element, we consider the possibility of intra as well as interplane pairing within a nearly antiferromagnetic Fermi liquid model. Solutions of a set of three coupled

K. R. Elder, Nicholas A. Gross, Bulbul Chakraborty, Nigel Goldenfeld

A continuum model derived from an atomistic Hamiltonian is used to examine the ordering kinetics in CuAu. A detailed description of the formation of the low and high temperature ordered and modulated superlattice states is given. The metastability of the modulated phase at low temperatures is shown to severely hinder creation of the ordered superlattice. For

Lei Gu, Bulbul Chakraborty

We have analyzed a non-randomly frustrated spin model which exhibits behavior remarkably similar to the phenomenology of structural glasses. The high-temperature disordered phase undergoes a strong first-order transition to a long-range ordered structure. Using Monte Carlo simulations, we have studied the behavior of the supercooled state by quenching to tem

P. S. Swain, A. O. Parry

Critical effects at complete and critical wetting in three dimensions are studied using a coupled effective Hamiltonian H[s(y),\ell]. The model is constructed via a novel variational principle which ensures that the choice of collective coordinate s(y) near the wall is optimal. We highlight the importance of a new wetting parameter Ω(T) which has a strong in

C. Gros, W. Wenzel, A. Fledderjohann, P. Lemmens

In a magnetic substance the gap in the Raman spectrum, Delta_R, is approximatively twice the value of the neutron scattering gap, Delta_S, if the the magnetic excitations (magnons) are only weakly interacting. But for CuGeO_3 the experimentally observed ratio Delta_R/Delta_S is approximatively 1.49-1.78, indicating attractive magnon-magnon interactions in th

Alvaro Corral, Albert Diaz-Guilera

A stochastic nonlinear partial differential equation is built for two different models exhibiting self-organized criticality, the Bak, Tang, and Wiesenfeld (BTW) sandpile model and the Zhang&#39;s model. The dynamic renormalization group (DRG) enables to compute the critical exponents. However, the nontrivial stable fixed point of the DRG transformation is u

Frank Tzschichholz, Helene Zanni

We reconsider a number of measurements for the overall hydration kinetics of tricalcium silicate pastes having an initial water to cement weight ratio close to 0.5. We find that the time dependent ratio of hydrated and unhydrated silica mole numbers can be well characterized by two power-laws in time, $x/(1-x)\sim (t/t_x)^ψ$. For early times $t < t_x$ we fin

B. Sriram Shastry

We point out the curious phenomenon of order by projection in a class of lattice Fermi systems near half filling. Enhanced pairing correlations of extended s-wave Cooper pairs result from the process of projecting out s-wave Cooper pairs, with negligible effect on the ground state energy. The Hubbard model is a particularly nice example of the above phenomen

Pawan Kumar

The stochastic excitation of solar oscillations due to turbulent convection is reviewed. A number of different observational results that provide test for solar p-mode excitation theories are described. I discuss how well the stochastic excitation theory does in explaining these observations. The location and properties of sources that excite solar p-modes a

William H. Waller, Theodore P. Stecher, the Ultraviolet Imaging Telescope, Science Team

Ultraviolet imaging of nearby disk galaxies reveals the star-forming activity in these systems with unprecedented clarity. UV images recently obtained with the Shuttle-borne Ultraviolet Imaging Telescope (UIT) reveal a remarkable variety of star-forming morphologies. The respective roles of tides, waves, and resonances in orchestrating the observed patterns

A. Crider, E. P. Liang, I. A. Smith, R. D. Preece

We report evidence that the asymptotic low-energy power law slope alpha (below the spectral break) of BATSE gamma-ray burst photon spectra evolves with time rather than remaining constant. We find a high degree of positive correlation exists between the time-resolved spectral break energy E_pk and alpha. In samples of 18 &#34;hard-to-soft&#34; and 12 &#34;tr

Karl Gebhardt, Carlton Pryor, T. B. Williams, James E. Hesser

We have used an Imaging Fabry-Perot Spectrophotometer with the Sub-arcsecond Imaging Spectrograph on the CFHT to measure velocities for 1534 stars in the globular cluster M15. Combined with previous velocity samples, the total number of stars with measured velocities in M15 is 1597. The velocity dispersion profile for M15 remains flat at a value of 11 km/s f

Chris Mihos, Stacy McGaugh, Erwin de Blok

Using analytic stability criteria, we demonstrate that, due to their low surface mass density and large dark matter content, LSB disks are quite stable against the growth of global nonaxisymmetric modes such as bars. However, depending on their (poorly constrained) stellar velocity dispersions, they may be only marginally stable against local instabilities.

R. B. Barreiro, J. L. Sanz, E. Martinez-Gonzalez, L. Cayon

We present properties of the peaks (maxima) of the CMB anisotropies expected in flat and open CDM models. We obtain analytical expressions of several topological descriptors: mean number of maxima and the probability distribution of the gaussian curvature and the eccentricity of the peaks. These quantities are calculated as functions of the radiation power s

Takashi Nakamura, Hideya Uehara, Takeshi Chiba

The lower limit of the mass of the first stars suggested recently may imply the formation of massive stars of mass greater than 8 solar mass irrespective of the details of the initial mass function. The production of heavy metals from the first stars will ensure a requisite for the existence of life without the anthropic principle.

Philip R. Maloney, Mitchell C. Begelman

A geometrically thin, optically thick, warped accretion disk with a central source of luminosity is subject to non-axisymmetric forces due to radiation pressure; the resulting torque acts to modify the warp. Initially planar accretion disks are unstable to warping driven by radiation torque, as shown in a local analysis by Pringle (1996) and a global analysi

Philip R. Maloney, Mitchell C. Begelman, J. E. Pringle

A geometrically thin, optically thick, warped accretion disk with a central source of luminosity is subject to non-axisymmetric forces due to radiation pressure; the resulting torque acts to modify the warp. In a recent paper, \cite{pri96} used a local analysis to show that initially planar accretion disks are unstable to warping driven by radiation torque.

Ezra Getzler

We present two explicit recursions which determine the elliptic Gromov-Witten invariants of CP^3 in terms of the rational ones, and give a table up to degree 5. Unlike the rational Gromov-Witten invariants, the coefficients are negative and fractional. In a further paper, we will prove that N^1_ab + (2n-1)N^0_ab/12 is the number of elliptic space curves thro

Jim Bryan, Marc Sanders

We study the large rank limit of the moduli spaces of framed bundles on the projective plane and the blown-up projective plane. These moduli spaces are identified with various instanton moduli spaces on the 4-sphere and $\cpbar $, the projective plane with the reverse orientation. We show that in the direct limit topology, these moduli spaces are homotopic t

V. Branchina, H. Mohrbach, J. Polonyi

It is shown that the four dimensional antiferromagnetic lattice phi4 model has the usual non-asymptotically free scaling law in the UV regime around the chiral symmetrical critical point. The theory describes a scalar and a pseudoscalar particle. A continuum effective theory is derived for low energies. A possibility of constructing a model with a single chi

V. Branchina, H. Mohrbach, J. Polonyi

Certain higher dimensional operators of the lagrangian may render the vacuum inhomogeneous. A rather rich phase structure of the phi4 scalar model in four dimensions is presented by means of the mean-field approximation. One finds para- ferro- ferri- and antiferromagnetic phases and commensurate-incommensurate transitions. There are several particles describ

D. V. Antonov

A correction to the Hamiltonian of the quark-antiquark system, arising due to the rigidity term in the gluodynamics string effective action, is obtained. This correction contains additional contributions to the orbital momentum of the system and several higher derivative operators. With the help of the derived Hamiltonian a rigid string-induced term in the H

P. F. Borges, H. Boschi-Filho, C. Farina

We show that the assumption of quasiperiodic boundary conditions (those that interpolate continuously periodic and antiperiodic conditions) in order to compute partition functions of relativistic particles in 2+1 space-time can be related with anyonic physics. In particular, in the low temperature limit, our result leads to the well known second virial coeff

J. Blümlein, N. Kochelev

The twist 2 and twist 3 contributions of the polarized deep-inelastic structure functions are calculated both for neutral and charged current interactions using the operator product expansion in lowest order in QCD. The relations between the different structure functions are determined. New integral relations are derived between the twist 2 contributions of

Paul S. Aspinwall

We consider heterotic string theories compactified on a K3 surface which lead to an unbroken perturbative gauge group of Spin(32)/Z2. All solutions obtained are combinations of two types of point-like instanton --- one ``simple type&#39;&#39; as discovered by Witten and a new type associated to the ``generalized second Stiefel-Whitney class&#39;&#39; as intr

D. Kutasov, E. Martinec

The string field theory of N=(2,1) heterotic strings describes a set of self-dual Yang-Mills fields coupled to self-dual gravity in 2+2 dimensions. We show that the exact classical action for this field theory is a certain complexification of the Green-Schwarz/Dirac-Born-Infeld string action, closely related to the four dimensional Wess-Zumino action describ

Konstantin Chetyrkin, Mikolaj Misiak, Manfred Munz

We present our results for three-loop anomalous dimensions necessary in analyzing $B{\to}X_sγ$ decay at the next-to-leading order in QCD. We combine them with other recently calculated contributions, obtaining a practically complete next-to-leading order prediction for the branching ratio ${\cal B}(B{\to}X_sγ) = (3.28 \pm 0.33) \times 10^{-4}$. The uncertain

Tomasz Brzezinski

It is shown that quantum Euclidean groups $E_q(2)$, $E_κ(2)$ and $E_κ(3)$ have the structure of generalised crossed products.

EROS collaboration, C. Renault, C. Afonso, E. Aubourg

We present final results from the first phase of the EROS search for gravitational microlensing of stars in the Magellanic Clouds by unseen deflectors (machos: MAssive Compact Halo Objects). The search is sensitive to events with time scales between 15 minutes and 200 days corresponding to deflector masses in the range 1.e-7 to a few solar masses. Two events

M. Martin, H. Kalechofsky, P. Foka, U. A. Wiedemann

We show that the formalism commonly used to implement Bose-Einstein correlations in Monte-Carlo simulations can lead to values of the two-particle correlator significantly smaller than unity, in the case of sources with strong position-momentum correlations. This is more pronounced when the phase space of the emitted particles is strongly reduced by experime

L. Andrianopoli, R. D&#39;Auria, S. Ferrara

A geometric formulation which describes extended supergravities in any dimension in presence of electric and magnetic sources is presented. In this framework the underlying duality symmetries of the theories are manifest. Particular emphasis is given to the construction of central and matter charges and to the symplectic structure of all D=4, N-extended theo

A. Frank, R. Lemus, F. Perez-Bernal, R. Bijker

We present a symmetry-adapted version of the vibron model and discuss an application to D_{3h} triatomic molecules: H_3^+, Be_3 and Na_3^+.

Jesus A. Alvarez Lopez, Yuri A. Kordyukov

For any Riemannian foliation F on a closed manifold M with an arbitrary bundle-like metric, leafwise heat flow of differential forms is proved to preserve smoothness on M at infinite time. This result and its proof have consequences about the space of bundle-like metrics on M, about the dimension of the space of leafwise harmonic forms, and mainly about the

Andrei N. Leznov, Emil A. Yuzbashyan

We explicitly obtain the $m$-soliton solutions of the (1+2)-dimensional matrix Davey-Stewartson equation from the known general solution of the matrix Toda chain with fixed ends. We write these solutions in terms of $m+m$ independent solutions of a pair of linear Shr\"odinger equations with Hermitian potentials.

Marcelo J. Rozenberg

We argue that, at low temperatures and well into the ferromagnetic phase, the physics of the manganase perovskites may be characterized by a correlated metallic state near a metal insulator transition where the orbital degrees of freedom play a main role. This follows from the observation that a two-band degenerate Hubbard model under a strong magnetic field

Arkadiusz Olech

The first catalog of chromospherically active and ellipsoidal variable stars in the OGLE database is presented. The periods, the observed magnitudes and colors, their values free of interstellar extinction, and Fourier coefficients of light modulation are given for 549 stars. New color-magnitude diagrams based on new color determinations are presented. The c

Andrew R Liddle

An introductory account is given of the modern understanding of the physics of the early Universe. Particular emphasis is placed on the paradigm of cosmological inflation, which postulates a period of accelerated expansion during the Universe's earliest stages. Inflation provides a possible origin for structure in the Universe, such as microwave background a

Oleg Andreev

In these notes I briefly outline SL(2) degenerate conformal field theories and their application to some related models, namely 2d gravity and N=2 discrete superconformal series.

Marek Czachor, Maciej Kuna

We present an off-shell indefinite-metric reformulation of the earlier on-shell positive-metric triple bracket generalization of the Dirac equation. The new version of the formalism solves the question of its manifest covariance.

J. M. Maillet, J. Sanchez de Santos

We study representation theory of Drinfel&#39;d twists, in terms of what we call F matrices, associated to finite dimensional irreducible modules of quantum affine algebras, and which factorize the corresponding (unitary) R matrices. We construct explicitly such factorizing F matrices for irreducible tensor products of the fundamental representations of the

Aric Hagberg, Ehud Meron

In bistable systems, the stability of front structures often influences the dynamics of extended patterns. We show how the combined effect of an instability to curvature modulations and proximity to a pitchfork front bifurcation leads to spontaneous nucleation of spiral waves along the front. This effect is demonstrated by direct simulations of a FitzHugh-Na

Fu-Guang Cao, Shan-de Yang

Saturation properties and liquid-gas phase transition of nucleus are analysed in the framework of Hatree-Fock theory. We modify Hill-Wheller formula with a finite-size-effect parameter by fitting the zero-temperature properties of nucleus. Employing Gogny effective interaction and phenomenological expression of Coulomb energy, we give the critical temperatur

David B. Kaplan, Aneesh V. Manohar

The nucleon-nucleon potential is analysed using the 1/N_c expansion of QCD. The NN potential is shown to have an expansion in 1/N_c^2, and the strengths of the leading order central, spin-orbit, tensor, and quadratic spin-orbit forces (including isospin dependence) are determined. Comparison with a successful phenomenological potential (Nijmegen) shows that

P. Mohr, T. Rauscher, H. Oberhummer, Z. Máté

For the determination of the $^{144}Sm-α$ optical potential we measured the angular distribution of $^{144}Sm(α,α)^{144}Sm$ scattering at the energy $E_{lab} = 20 MeV$ with high accuracy. Using the known systematics of $α$-nucleus optical potentials we are able to derive the $^{144}Sm-α$ optical potential at the astrophysically relevant energy $E_{c.m.} = 9.

Peter Teichner

We show that if the lower central series of the fundamental group of a closed oriented $3$-manifold stabilizes then the maximal nilpotent quotient is a cyclic group, a quaternion $2$-group cross an odd order cyclic group, or a Heisenberg group. These groups are well known to be precisely the nilpotent fundamental groups of closed oriented $3$-manifolds.

A. D. Kennedy

A new formalism is given for the renormalization of quantum field theories to all orders of perturbation theory, in which there are manifestly no overlapping divergences. We prove the BPH theorem in this formalism, and show how the local subtractions add up to counterterms in the action. Applications include the renormalization of lattice perturbation theory

J. -Q. Liang, H. J. W. Mueller-Kirsten, Jian-Ge Zhou, F. Zimmerschied

The tunneling effect of a periodic potential with an asymmetric twin barrier per period is calculated using the instanton method. The model is derived from the Hamiltonian of a small ferromagnetic particle in an external magnetic field using the spin-coherent-state path integral. The instantons in two neighbouring barriers differ and lead to different level

Cesar Gomez

We study the effect of mirror symmetry for K3 surfaces on D-brane probe physics. The case of elliptically fibered K3 surfaces is considered in detail. In many cases, mirror can transform a singular fiber of Kodaira&#39;s type ADE into sets of singular fibers of type I_1 (II) with equal total Euler number, but vanishing contribution to the Picard number of th

M. C. Diamantini, F. Quevedo, C. A. Trugenberger

We consider several aspects of `confining strings&#39;, recently proposed to describe the confining phase of gauge field theories. We perform the exact duality transformation that leads to the confining string action and show that it reduces to the Polyakov action in the semiclassical approximation. In 4D we introduce a `$θ$-term&#39; and compute the low-ene

Burkhard Kleihaus, Jutta Kunz

We construct static axially symmetric solutions of SU(2) Einstein-Yang-Mills-dilaton theory. Like their spherically symmetric counterparts, these solutions are nonsingular and asymptotically flat. The solutions are characterized by the winding number n and the node number k of the gauge field functions. For fixed n with increasing k the solutions tend to ``e

Artemio González-López, Niky Kamran

A generalization of the classical one-dimensional Darboux transformation to arbitrary n-dimensional oriented Riemannian manifolds is constructed using an intrinsic formulation based on the properties of twisted Hodge Laplacians. The classical two-dimensional Moutard transformation is also generalized to non-compact oriented Riemannian manifolds of dimension

O. Babelon, D. Bernard, F. A. Smirnov

We review and summarize recent works on the relation between form factors in integrable quantum field theory and deformation of geometrical data associated to hyper-elliptic curves. This relation, which is based on a deformation of the Riemann bilinear identity, in particular leads to the notion of null vectors in integrable field theory and to a new descrip

T. Hatsuda, T. Kunihiro, T. Tanaka

The notion of the optimized perturbation, which has been successfully applied to energy eigenvalues, is generalized to treat wave functions of quantum systems. The key ingredient is to construct an envelope of a set of perturbative wave functions. This leads to a condition similar to that obtained from the principle of minimal sensitivity. Applications of th

D. Rainwater, D. Summers, D. Zeppenfeld

Multijet events at large transverse energy (sum E_T > 420 GeV) and large multijet invariant mass (M_jets > 600 GeV) have been studied by the CDF Collaboration at the Fermilab Tevatron. The observed jet multiplicity distribution can be understood in a QCD inspired exponentiation model, in regions of phase space which require going beyond fixed order perturbat

A. V. Kotikov, D. V. Peshekhonov

We analyse the proton and deutron data on spin dependent asymmetry $A_1(x,Q^2)$ supposing the DIS structure functions $g_1(x,Q^2)$ and $F_3(x,Q^2)$ have the similar $Q^2$-dependence. As a result, we have obtained that $Γ_1^p - Γ_1^n = 0.190 \pm 0.038$ at $Q^2= 10 GeV^2$ and $Γ_1^p - Γ_1^n = 0.165 \pm 0.026$ at $Q^2= 3 GeV^2$, what is in the best agreement wi

Rudolph C. Hwa

This is the summary talk of the Nijmegen Workshop. The topics are: 1. Introduction, 2. Phenomenology of mature topics, 2.1 Bose-Einstein correlations, 2.2 Fluctuations, 2.3 Phenomenology of QCD and other dynamics, 3. Experiments not driven by conventional theory, 3.1 Search for DCC, 3.2 Soft-photon production, 4. Theory not driven by conventional experiments

Xuemin Jin, R. L. Jaffe

We study the kinematics and cross section of the scattering process $e p \rightarrow e Σ^+$. The cross section is expressed in terms of complex form factors characterizing the hadron vertices. We estimate the cross section for small momentum transfer using known experimental information. To first order in the momentum transfer, we obtain a model independent

Pat Kalyniak, Ivan Melo

Many extensions of the Standard Model include extra fermions. We here consider a model containing Dirac neutral heavy leptons in addition to massless neutrinos. These neutral heavy leptons can be produced singly along with a massless neutrino in $e^+ e^-$ and $μ^+ μ^-$ collisions. The production rates depend on the neutral heavy lepton masses and mixing para