arXiv papers from February 1994

Makoto Natsuume, Joseph Polchinski

The $c=1$ matrix model is equivalent to $1+1$ dimensional string theory. However, the tachyon self-interaction in the former is local, while in the latter it is nonlocal due to the gravitational, dilaton and higher string fields. By studying scattering of classical pulses we show that the appropriate nonlocal field redefinition converts the local matrix mode

Subhendra Mohanty, Prafulla Kumar Panda

The orbital period of the binary pulsar PSR 1913+16 has been observed to decrease at the rate of $2.40\times 10^{-12}$ s/s which agrees with the prediction of the quadropole formula for gravitational radiation to within one percent. The decrease in orbital period may also occur by radiation of other massless particles like scalars and pseudoscalar Nambu-Gold

Igor Herbut, Zlatko Tesanovic

We present a theory of vortex liquid-to-solid transition in homogeneous quasi 2D superconductors. The free energy is written as a functional l of density of zeroes of the fluctuating order parameter. The transition is weakly first-order and well below the Hc2(T) line. Transition temperature, discontinuities of the average Abrikosov ratio and of the average s

L. I. Ronkin, A. M. Russakovskii

We give a complete description of divisors of entire periodic functions in $\C^n$ with plane zeros.

Vladimir Logvinenko, Alexander Russakovskii

Cartwright-type and Bernstein-type theorems, previously known only for functions of exponential type in $\C^n$, are extended to the case of functions of arbitrary order in a cone.

T. Brodkorb, E. Mirkes

Complete next-to leading order QCD predictions for (2+1) jet cross sections and jet rates in deep inelastic scattering (DIS) based on a new parton level Monte Carlo program are presented. All relevant helicity contributions to the total cross section are included. Results on total jet cross sections as well as differential distributions in the basic kinemati

S. Colombi

I propose a method to fit the probability distribution function (hereafter PDF) of the large scale density field rho, motivated by a Lagrangian version of the continuity equation. It consists in applying the Edgeworth expansion to the quantity Phi=log rho - < log rho >. The method is tested on the matter particle distribution in two cold dark matter N-body s

M. Asakawa

In a recent Letter, Geiger presents calculations of the dilepton emission from the early stage of ultrarelativistic heavy ion collisions using the parton cascade model (PCM). He shows that the $M_\perp$ scaling is not observed. In this Comment, we point out that this is largely due to a defect in the PCM.

Boldizsar Janko, Anders Smith, Vinay Ambegaokar

We investigate superconductivity in a grand canonical ensemble with {\it fixed number parity} (even or odd). In the low temperature limit we find small corrections to the BCS gap equation and energy spectrum $E(k)$. The even-odd free energy difference in the same limit decreases linearly with temperature, in accordance with the behavior observed experimental

D. Lu, T. Mefford, G. Song, R. H. Landau

The Vincent--Phatak procedure for solving the momentum-space Schrodinger equation with combined Coulomb-plus-short-range potentials is extended to angular momentum states coupled by an optical potential---as occurs in spin 1/2 times 1/2 scattering. A generalization of the Blatt--Biedenharn phase shift parameterization is derived and applied to 500 MeV polari

A. Pelizzola

In the present paper we show how non--classical, quite accurate, critical exponents can be extracted in a very simple way from the Pad\'e analysis of the results obtained by mean field like approximation schemes, and in particular by the cluster variation method. We study the critical behavior of the Ising model on several lattices (quadratic, triangular, si

E. Elizalde

The two-dimensional inhomogeneous zeta-function series (with homogeneous part of the most general Epstein type): \[ \sum_{m,n \in \mbox{\bf Z}} (am^2+bmn+cn^2+q)^{-s}, \] is analytically continued in the variable $s$ by using zeta-function techniques. A simple formula is obtained, which extends the Chowla-Selberg formula to inhomogeneous Epstein zeta-functio

E. Elizalde, A. G. Jacksenaev, S. D. Odintsov, I. L. Shapiro

A higher-derivative, interacting, scalar field theory in curved spacetime with the most general action of sigma-model type is studied. The one-loop counterterms of the general theory are found. The renormalization group equations corresponding to two different, multiplicatively renormalizable variants of the same are derived. The analysis of their asymptotic

Jürgen Fuchs, Alexander Ganchev, Peter Vecsernyés

Rational Hopf algebras (certain quasitriangular weak quasi-Hopf $^*$-algebras) are expected to describe the quantum symmetry of rational field theories. In this paper methods are developped which allow for a classification of all rational Hopf algebras that are compatible with some prescribed set of fusion rules. The algebras are parametrized by the solution

E. Betak

Single-particle radiative mechanism of $\gamma$ emission embedded into the pre-equilibrium exciton model is used to calculate the $\gamma$ emission from a decay of $^{160}$Er$^{*}$ created in two different ways. The initial stage of a reaction is described using momentum-space overlaps of colliding nuclei. We can reproduce the main features of the observed $

R. Amorim, J. Barcelos-Neto

We study the Chern-Simons theory coupled to matter field by means of an effective Lagrangian obtained from the Batalin-Fradkin-Vilkovisky formalism. We show that there is no rotational anomaly for any proper gauge we choose.

K. Pinn, A. Pordt, C. Wieczerkowski

Nontrivial fixed points of the hierarchical renormalization group are computed by numerically solving a system of quadratic equations for the coupling constants. This approach avoids a fine tuning of relevant parameters. We study the eigenvalues of the renormalization group transformation, linearized around the non-trivial fixed points. The numerical results

P. Boschung, O. Brodbeck, F. Moser, N. Straumann

We prove the instability of the gravitating regular sphaleron solutions of the $SU(2)$ Einstein-Yang-Mills-Higgs system with a Higgs doublet, by studying the frequency spectrum of a class of radial perturbations. With the help of a variational principle we show that there exist always unstable modes. Our method has the advantage that no detailed knowledge of

Erio Tosatti, Nicola Manini

We propose that thermal electron attachment to C$_{60}$ should occur preferentially in the p-wave channel, following an analysis of the vibron excitation spectrum of C$_{60}^-$. A very simple model based on this idea is shown to account very well for recent attachment data. The unexplained activation energy of $\approx$ 0.26 eV found experimentally is attrib

S. Bellucci, V. Gribanov, S. Krivonos, A. Pashnev

In this letter we consider the nonlinear realizations of the classical Polyakov's algebra $W_3^{(2)}$. The coset space method and the covariant reduction procedure allow us to deduce the Boussinesq equation with interchanged space and evolution coordinates. By adding one more space coordinate and introducing two copies of the $W_3^{(2)}$ algebra, the same me

B. Alles, M. Campostrini, L. Del Debbio, A. Di Giacomo

We present preliminary results on the proton spin structure function at zero momentum, in the quenched approximation. Our calculation makes use of a nonperturbative means of determining the multiplicative renormalization of the topological charge density.

Ewald Mueller, Matthias Steinmetz

An efficient algorithm for solving Poisson's equation in two and three spatial dimensions is discussed. The algorithm, which is described in detail, is based on the integral form of Poisson's equation and utilizes spherical coordinates and an expansion into spherical harmonics. The solver can be applied to and works well for all problems for which the use of

Cedric Lacey, Shaun Cole

We have made a detailed comparison of the results of large N-body simulations with the analytical description of the merging histories of dark matter halos presented in Lacey & Cole 1993, which is based on an extension of the Press- Schechter method (Bond etal 1991,Bower 1991). We find the analytical predictions for the halo mass function, merger rates and f

I. L. Shapiro

In the framework of the recently proposed asymptotically finite gauge models the cosmological constant is essentially weakened by quantum effects. The next (and more general) claim is that the coupling between quantum fields may suppress their contributions to the induced cosmological constant.

Tadashi OKAI

Rotating stringy black hole solutions with non-vanishing dilaton $\phi$, antisymmetric tensor $B_{\mu\nu}$, and $U(1)$ gauge field $A_{\mu}$ are investigated. Both Boyer-Lindquist-like and Kerr-Schild-like coordinate are constructed. The latter is utilised to construct the analytically extended spacetime. The global structure of the resulting extended spacet

Heiko Rieger

A characteristic feature of the non--equilibrium dynamics of real spin glasses at low temperatures are strong aging effects. These phenomena can be manipulated by changing the external parameters in various ways: a thermo-cycling experiment consists for instance of a short heat pulse during the waiting time, by which the relaxation might be strongly affected

R. Baier, O. K. Kalashnikov

The nonabelian screening potential is calculated in the temporal axial gauge. The Slavnov-Taylor identity is used to construct the three-gluon vertex function from the inverse gluon propagator. After solving the Schwinger - Dyson equation beyond leading order we find that the obtained momentum dependence of the gluon self-energy at high temperature does not

Toshiya Kawai, Kenji Mohri

Several aspects of (0,2) Landau-Ginzburg orbifolds are investigated. Especially the elliptic genera are computed in general and, for a class of models recently invented by Distler and Kachru, they are compared with the ones from (0,2) sigma models. Our formalism gives an easy way to calculate the generation numbers for lots of Distler-Kachru models even if t

I. I. Bigi, M. A. Shifman, N. G. Uraltsev, A. I. Vainshtein

The key quantity of the heavy quark theory is the quark mass $m_Q$. Since quarks are unobservable one can suggest different definitions of $m_Q$. One of the most popular choices is the pole quark mass routinely used in perturbative calculations and in some analyses based on heavy quark expansions. We show that no precise definition of the pole mass can be gi

Eric G. Blackman, George B. Field

We derive the fully relativistic Ohm's law for an electron-positron plasma. The absence of non-resistive terms in Ohm's law and the natural substitution of the 4-velocity for the velocity flux in the relativistic bulk plasma equations do not require the field gradient length scale to be much larger than the lepton inertial lengths, or the existence of a fram

Goran Senjanović

We review the issue of neutrino mass by concentrating on the minimal extensions of the standard model. In particular, we emphasize the role that gravitation may play in this regard and discuss the central aspects of the see-saw mechanism of generating neutrino mass, including the possibility of the see-saw scale being close to the eelectroweak scale.

M. Kontsevich, Yu. Manin

The paper is devoted to the mathematical aspects of topological quantum field theory and its applications to enumerative problems of algebraic geometry. In particular, it contains an axiomatic treatment of Gromov-Witten classes, and a discussion of their properties for Fano varieties. Cohomological Field Theories are defined, and it is proved that tree level

Arild Skjold, Per Osland

We consider an extension of the Standard Model where some Higgs particle is not an eigenstate of $CP$, and discuss the possibility of extracting signals of the resulting $CP$ violation. In the case of Higgs decay to four fermions we study correlations among momenta of the final-state fermions. We discuss observables which may demonstrate presence of $CP$ vio

Taichiro KUGO, Joe SATO

Dynamical symmetry breaking is studied in an E_6 GUT model of a single generation of fermions with strong 4-fermi interactions. The effective potential is analyzed analytically by the help of Michel's conjecture and the result is confirmed numerically. We find that the E_6 symmetry is spontaneously broken either to F_4 or to Sp(8) or G_2 or SU(3), depending

Tonatiuh Matos, Jerzy Plebanski

We present a method for generating exact solutions of Einstein equations in vacuum using harmonic maps, when the spacetime possesses two commutating Killing vectors. This method consists in writing the axisymmetric stationry Einstein equations in vacuum as a harmonic map which belongs to the group SL(2,R), and decomposing it in its harmonic "submaps". This m

Rajan Gupta, Jeffrey Mandula

We present a method to estimate the matrix element of the singlet axial current within a polarized proton state using lattice QCD. The method relies on using the Adler-Bell-Jackiw anomaly and gives the desired result in the chiral limit. We show that this method fails in the quenched approximation. For heavy quarks one does not expect much difference between

Alakabha Datta, Sandip Pakvasa, Utpal Sarkar

We calculate the two loop contribution to the predictions of the mass scales in an SO(10) grand unified theory. We consider the modified unification scale boundary conditions due to the non-renormalizable higher dimensional terms arising from quantum gravity or spontaneous compactification of extra dimensions in Kaluza-Klein type theory. We find the range of

Sandip Pakvasa

Possible explanations of solar neutrino and atmospheric neutrino anomalies are summarized and future tests discussed.

Stefan Lenz

Quantum scattering at zero energy is studied with stochastic methods. A path integral representation for the scattering cross section is developed. It is demonstrated that Monte Carlo simulation can be used to compare effective potentials which are frequently used in multiple scattering with the exact result.

C. L. Kane, M. P. A. Fisher, J. Polchinski

Current Luttinger liquid edge state theories for filling $\nu=2/3$ predict a non-universal Hall conductance, in disagreement with experiment. Upon inclusion of random edge tunnelling we find a phase transition into a new disordered-dominated edge phase. An exact solution of the random model in this phase gives a quantized Hall conductance of 2/3 and a neutra

Leonard S. Kisslinger, Zhenping Li

The mass splittings of the pseudoscalar and vector D and B light-heavy quark systems have been calculated using the method of QCD sum rules. Electromagnetic, quark mass, and nonperturbative QCD effects are all included. The results are in good agreement with experiment. A measurement of isospin splitting for the vector B mesons would give valuable informatio

A. T. Bernardes, J. G. Moreira

A fiber bundle model in $(1+1)$-dimensions for the breaking of fibrous composite matrix is introduced. The model consists of $N$ parallel fibers fixed in two plates. When one of the plates is pulled in the direction parallel to the fibers, these can be broken with a probability that depends on their elastic energy. The mechanism of rupture is simulated by th

Marc Kamionkowski, Lawrence M. Krauss, M. Ted Ressell

Predicted rates for direct and indirect detection of dark-matter neutralinos depend in general on the spin content of the nucleon. Neutralinos that are predominantly $B$-ino are the likeliest candidates for detection via spin-dependent interactions. Uncertainties in the measured spin content of the nucleon may lead to dramatic uncertainties in the rates for

N. R. F. Braga, H. Montani

We construct the chiral Wess-Zumino term as a solution for the Batalin-Vilkovisky master equation for anomalous two-dimensional gauge theories, working in an extended field-antifield space, where the gauge group elements are introduced as additional degrees of freedom. We analyze the Abelian and the non-Abelian cases, calculating in both cases the BRST gener

J. Rayford Nix

We discuss future directions in the development of classical hadrodynamics for extended nucleons, corresponding to nucleons of finite size interacting with massive meson fields. This new theory provides a natural covariant microscopic approach to relativistic nucleus-nucleus collisions that includes automatically spacetime nonlocality and retardation, nonequ

B. Enriquez

We propose a quantum lattice version of Feigin and E. Frenkel's constructions, identifying the KdV differential polynomials with functions on a homogeneous space under the nilpotent part of $\widehat{s\ell}_2$. We construct an action of the nilpotent part $U_q\widehat n_+$ of $U_q\widehat{s\ell}_2$ on their lattice counterparts, and embed the lattice variabl

D. Bernard, A. Leclair

We demonstrate that for the sine-Gordon theory at the free fermion point, the 2-point correlation functions of the fields $\exp (i\al \Phi )$ for $0< \al < 1$ can be parameterized in terms of a solution to a sinh-Gordon-like equation. This result is derived by summing over intermediate multiparticle states and using the form factors to express this as a Fred

I. V. Kolokolov

For a given wave function one can define a quantity $\mu_E$ having a meaning of its inverse spatial size. The Laplace transform of the distribution function $P(\mu_E)$ is calculated analytically for a 1D disordered sample with a finite length $L$.

Dipak Munshi, Varun Sahni, Alexei A. Starobinsky

We compare different nonlinear approximations to gravitational clustering in the weakly nonlinear regime, using as a comparative statistic the evolution of non-Gaussianity which can be characterised by a set of numbers $S_p$ describing connected moments of the density field at the lowest order in $<\delta^2>$: $<\delta^n>_c \simeq S_n<\delta^2>^{n-1}$. Gener

Yang Sun, Shuxian Wen, Da Hsuan Feng

A generic explanation for the recently observed anomalous crossing frequencies in odd proton rare earth nuclei is given. As an example, the proton ${1\over 2} [541]$ band in $^{175}$Ta is discussed in detail by using the angular momentum projection theory. It is shown that the quadrupole pairing interaction is decisive in delaying the crossing point and the

Gernot Muenster, Jochen Heitger

In three-dimensional systems of the Ising universality class the ratio of correlation length amplitudes for the high- and low-temperature phases is a universal quantity. Its field theoretic determination apart from the $\epsilon$-expansion represents a gap in the existing literature. In this article we present a method, which allows to calculate this ratio b

H. Navelet, R. Peschanski, S. Wallon

We discuss the phenomenological extraction of the leading $ j$-plane singularity from singlet structure functions $ F_s $ measured at small $ x. $ Using a saddle-point method we show that $ {\rm d ln} F_s /{\rm d ln}{1 \over x} $ is a suitable observable for this purpose in the region $x \le 10^{-2}.$ As an application, we confront and distinguish in a model

Tom Schork, Peter Fulde

We consider a magnetic impurity which interacts by hybridization with a system of strongly correlated conduction electrons. The latter are described by a Hubbard Hamiltonian. By means of a canconical transformation the charge degrees of freedom of the magnetic impurity are eliminated. The resulting effective Hamiltonian $H_{\rm eff}$ is investigated and vari

P. Aurenche F. W. Bopp R. Engel D. Pertermann J. Ranft, S. Roesler

A new version of a Monte Carlo Program for hadronic multi-particle production is presented. It is based on the two-component Dual Parton Model which includes the dual topological unitarization of soft and hard cross sections. The model treats both soft (low $p_{\perp}$) and hard (minijet, large $p_{\perp}$) processes in a unified and consistent way. The unif

Mark Gross

This paper gives a simple example of a family of Calabi-Yaus of any dimension with canonical singularities of dimension one, whose Kuranishi space is singular. Thus the Bogomolov-Tian-Todorov unobstructedness theorem is not true for Calabi-Yaus with canonical singularities.

Michiyasu Nagasawa, Masahiro Kawasaki

We examine the collapse of an axion domain wall bounded by an axionic string. It is found that the collapse proceeds quickly and axion domain walls disappear. However axions are emitted in the collapse and its energy density increases during radiation dominated era and contributes significantly to the present mass density of the universe. In particular the a

B. Basu-Mallick

A novel Hopf algebra $ ( {\tilde G}_{r,s} )$, depending on two deformation parameters and five generators, has been constructed. This $ {\tilde G}_{r,s}$ Hopf algebra might be considered as some quantisation of classical $GL(2) \otimes GL(1) $ group, which contains the standard $GL_q(2)$ quantum group (with $ q=r^{-1} $) as a Hopf subalgebra. However, we int

G. von Gehlen

Using finite-size-scaling methods, we study the quantum chain version of the spin-$1$-Blume-Capel model coupled to an imaginary field. The aim is to realize higher order non-unitary conformal field theories in a simple Ising-type spin model. We find that the first ground-state level crossing in the high-temperature phase leads to a second-order phase transit

T. Kawano, Y. Kikukawa

Being inspired by Kaplan's proposal for simulating chiral fermions on a lattice, we examine the continuum analog of his domain-wall construction for two-dimensional chiral Schwinger models. Adopting slightly unusual dimensional regularization, we explicitly evaluate the one-loop effective action in the limit that the domain-wall mass goes to infinity. For an

S. Jadach, B. F. L. Ward, S. A. Yost

Recently, the L3 collaboration has reported the observation of four events in the reactions e+ e- --> L+ L- + (2 Photons), L = e, mu, tau, with the invariant photon pair mass near 60 GeV in a data sample collected in the L3 detector corresponding to 950,000 produced Z0's. More recently, more data from the other LEP collaborations have become available. In th

S. Charlot, J. Silk

We use new models of stellar population synthesis to estimate the fraction of stars formed during the last major bursts of star formation in E/S0 galaxies in low-redshift clusters ($z\simlt0.4$) from the spectral signatures of intermediate-age stars. We find that the mass fraction of stars formed in late bursts in early-type galaxies in clusters must have de

T. Kamon, J. Lopez, P. McIntyre, J. White

Following the termination of the Superconducting Super Collider, there is an urgent need to develop a strategic plan for the future of high energy physics and an accompanying vision to guide the priorities of the U.S. program. This document proposes such a strategic plan and presents a singular opportunity for the U.S. program. The existing hadron collider a

Pablo Laguna

Smoothed particle hydrodynamics (SPH) discretization techniques are generalized to develop a method, smoothed particle interpolation (SPI), for solving initial value problems of systems of non-hydrodynamical nature. Under this approach, SPH is viewed as strictly an interpolation scheme and, as such, suitable for solving general hyperbolic and parabolic equat

Waleed A. Al-Salam

In this paper we characterize the Rogers q-Hermite polynomials as the only orthogonal polynomial set which is also ${\cal D}_q$-Appell where ${\cal D}_q $ is the Askey-Wilson finite difference operator.

Ronald Dickman, Eugene M. Chudnovsky

We study a harmonic triangular lattice, which relaxes in the presence of a weak, short-wavelength periodic potential. Monte Carlo simulations reveal that the elastic lattice has only short-ranged positional correlations, despite the absence of defects in either lattice. Long-range orientational order, however, persists in the presence of the background. Our

X. -M. Fan, D. Tytler

We present optical spectra of QSO HS~1946+7658 with either high resolution (FWHM=10 km/s) or high signal to noise ratio (SNR=40-100). We find 113 Lyman alpha and six metal line systems. The metal systems at Zabs=2.844 and 3.050 have complex velocity structures. We find that the system at 2.844 is a damped Ly-a absorption system, with neutral hydrogen column

Ambar Sengupta

We prove that for $SU(2)$ and $SO(3)$ quantum gauge theory on a torus, holonomy expectation values with respect to the Yang-Mills measure $d\mu_T(\o) =N_T^{-1}e^{-S_{YM}(\o)/T}[{\cal D}\o]$ converge, as $T\downarrow 0$, to integrals with respect to a symplectic volume measure $\mu_0$ on the moduli space of flat connections on the bundle. These moduli spaces

K. Gebhardt, C. Pryor, T. B. Williams, J. E. Hesser

We report the first use of the Rutgers Imaging Fabry-Perot Spectrophotometer to study the dynamics of the cores of globular clusters. We have obtained velocities for cluster stars by tuning the Fabry-Perot to take a series of narrow-band images at different wavelengths across one of the Na D (5890 AA) absorption lines. Measuring the flux in every frame yield

K. C. Chase, A. Z. Mekjian

A general model for the fragmentation of a two-component system (e.g. protons and neutrons) is proposed and solved exactly. The extension of this model to any number of components is also shown to be exactly solvable. A connection between this models and the permutation group is discussed. The notion of isotopic equivalence is defined in order to evaluate th

Yosef Nir

Within the Standard Model, $x_s$ (the mixing parameter in the $B_s-\bar B_s$ system) is constrained to the range $7 \leq x_s\leq 40$. We point out that if New Physics contributes significantly to $x_d$ (the mixing parameter in the $B_d-\bar B_d$ system), then $2 \leq x_s\leq 7$ is possible without any fine-tuned cancellations between the Standard Model and t

Riccardo Capovilla, Octavio Obregon

We show that the quantum super-minisuperspace of N=1 supergravity with $\Lambda \ne 0 $ has no non-trivial physical states for class A Bianchi models. Hence, in super quantum cosmology, the vanishing of $\Lambda$ is a condition for the existence of the universe. We argue that this result implies that in full supergravity with $\Lambda$ there are no non-trivi

R. V. Gavai, R. M. Godbole

We use the high statistics E-772 data on the nuclear dependence of the production of quarkonia $(J/\psi$ and $\Upsilon)$ and dimuons at large transverse momentum $(p_T)$ in $p$-$A$ collisions to get information about the gluonic EMC effect. We find a satisfactory quantitative agreement of the theoretical predictions with the data although none of the models

Jarmo Hietarinta

Zamolodchikov's tetrahedron equations, which were derived by considering the scattering of straight strings, can be written in three different labeling schemes: one can use as labels the states of the vacua between the strings, the states of the string segments, or the states of the particles at the intersections of the strings. We give a detailed derivation

Xiao-Gang Wen

We studied low energy effects of impurities in several chiral 1D electron systems that contain only excitations moving in one direction. We first considered single-impurity scattering between two branches of 1D chiral Luttinger liquids. The general form of impurity scattering matrix was found which, some times, allow the chemical potentials on the outgoing b

A. J. Buras, M. E. Lautenbacher, M. Misiak, M. M"unz

We analyze the direct CP violation in the rare decay K_L --> Pi^0 e+e- with QCD effects taken into account consistently in the next-to-leading order. We calculate the two-loop mixing between the four-quark \Delta S=1 operators and the operator Q_7V = (sd)_(V-A)(ee)_V in the NDR and HV renormalization schemes. Using the known two-loop anomalous dimension matr

Danny Birmingham, Mark Rakowski

We explicitly construct a series of lattice models based upon the gauge group $Z_{p}$ which have the property of subdivision invariance, when the coupling parameter is quantized and the field configurations are restricted to satisfy a type of mod-$p$ flatness condition. The simplest model of this type yields the Dijkgraaf-Witten invariant of a $3$-manifold a

I. S. Towner, A. C. Hayes

Expressions for the P,T-violating NN potentials are derived for $\pi$, $\rho$ and $\omega$ exchange. The nuclear matrix elements for $\rho$ and $\omega$ exchange are shown to be greatly suppressed, so that, under the assumption of comparable coupling constants, $\pi$ exchange would dominate by two orders of magnitude. The ratio of P,T-violating to P-violatin

M. Cavicchi, A. Vairo

We solve the Bethe-Salpeter equation for hydrogenic bound states by choosing an appropriate interaction kernel $K_c$. We want to use our solution to calculate up to a higher order the hydrogen Lamb-shift, and as a first application we present up to order $\left(\aa / \pi\right)(\za)^7$ the contribution of the lowest order self-energy graph, calculated {\it e

M. S. Ody, L. H. Ryder

It is shown that time-independent solutions to the (2+1)-dimensional non- linear O(3) sigma model may be placed in correspondence with surfaces of constant mean curvature in three-dimensional Euclidean space. The tools required to establish this correspondence are provided by the classical differential geometry of surfaces. A constant-mean-curvature surface

G. Kalbermann, L. L. Frankfurt, J. M. Eisenberg

We consider a two-nucleon system described by two different skyrmion models that provide attraction for the central NN potential. One of these models is based on the product ansatz and the other on dilaton coupling. Within these models we ask the question, To what degree does the nucleon swell or shrink when the internucleon separation distance is appropriat

Per Dahlqvist

We discuss zeta functions, and traces of the associated weighted evolution operators for intermittent Hamiltonian systems in general and for the Sinai billiard in particular. The intermittency of this billiard is utilized so that the zeta functions may be approximately expressed in terms of the probability distribution of laminar lengths. In particular we st

A. Bovier, J. -M. Ghez

We comment on some recent investigations on the electronic properties of models associated to the Thue-Morse chain and point out that their conclusions are in contradiction with rigorously proven theorems and indicate some of the sources of these misinterpretations. We briefly review and explain the current status of mathematical results in this field and di

Misao Sasaki

We present a method of post-Newtonian expansion to solve the homogeneous Regge-Wheeler equation which describes gravitational waves on the Schwarzschild spacetime. The advantage of our method is that it allows a systematic iterative analysis of the solution. Then we obtain the Regge-Wheeler function which is purely ingoing at the horizon in closed analytic f

David N. Spergel, Ue-Li Pen, Marc Kamionkowski, Naoshi Sugiyama

( to appear in: Proceedings of the Nishonomiya Yukawa Memorial Symposium Edited by M. Sasaki) There are several models for generating fluctuations in an open universe that are compatible with the microwave background fluctuations detected by COBE {\it and} observations of large scale structure. Topological defects, such as strings and textures, appear to be

Luca Amendola

We study the effect of the non-Gaussian clustering of galaxies on the statistics of pencil beam surveys. We find that the higher order moments of the galaxy distribution play an important role in the probability distribution for the power spectrum peaks. Taking into account the observed values for the kurtosis of galaxy distribution we derive the general pro

D. A. Lowe, L. Susskind, J. Uglum

The commutator of string fields is considered in the context of light cone string field theory. It is shown that the commutator is in general non--vanishing outside the string light cone. This could have profound implications for our understanding of the localization of information in quantum gravity.

H. J. Schulz

The application of functional integral methods and the Hubbard--Stratonovich transformation to the Hubbard model is discussed. For the attractive case, using a simple gauge transformation of the superconducting order parameter field, the effective action for the low-energy phase excitations is derived. Inclusion of the electromagnetic field is straightforwar

F. P. Pijpers, J. R. Pardo, V. Bujarrabal

We present the results of a short time scale monitoring of SiO maser emission (v=1 J=1-0 transition) in four known strong sources. These sources were monitored nightly for a period of about a month. The aim of these observations is to investigate the possible presence of variations in the maser lines on time scales of a few days to weeks, due to sound waves

Christopher King, Ambar Sengupta

We relate the semiclassical limit of the quantum Yang-Mills partition function on a compact oriented surface to the symplectic volume of the moduli space of flat connections, by using an explicit expression for the symplectic form. This gives an independent proof of some recent results of Witten and Forman.

J. A. Nieminen, T. Ala- Nissila

Dynamics of spreading of small droplets on surfaces has been studied by the molecular dynamics method. Simulations have been performed for mixtures of solvent and dimer, and solvent and tetramer droplets. For solvent particles and dimers, layering occurs leading to stepped droplet shapes. For tetramers such shapes occur for relatively deep and strong surface

Christina M. Bird

Formation theories for central dominant galaxies in clusters require them to be located at the minimum of the cluster gravitational potential. However, 32\% (8 out of 25) of the clusters with more than 50 measured redshifts have central galaxies with significant velocity offsets (with respect to other cluster members). By studying their velocity distribution

Peter Schupp, Paul Watts

We extend the universal differential calculus on an arbitrary Hopf algebra to a ``universal Cartan calculus''. This is accomplished by introducing inner derivations and Lie derivatives which act on the elements of the universal differential envelope. A new algebra is formulated by incorporating these new objects into the universal differential calculus toget

H. Lu, C. N. Pope, X. J. Wang, S. C. Zhao

BRST operators for two-dimensional theories with spin-2 and spin-$s$ currents, generalising the $W_3$ BRST operator of Thierry-Mieg, have previously been obtained. The construction was based on demanding nilpotence of the BRST operators, making no reference to whether or not an underlying $W$ algebra exists. In this paper, we analyse the known cases ($s=3$,

C. R. Allton, M. Crisafulli, V. Lubicz, G. Salina

We present a calculation of $f_B$ in the static limit, obtained by numerical simulation of quenched QCD, at $\beta=6.2$ on a $18^3 \times 64$ lattice, using the SW-Clover quark action. The decay constant has been extracted by studying heavy(static)-light correlation functions of different smeared operators, on a sample of 220 gauge field configurations. We h

Adrian L. Melott

I report on controlled comparison of gravitational approximation schemes linear/lognormal/adhesion/frozen-flow/Zel'dovich(ZA) and ZA's second--order generalization. In the last two cases we also created new versions of the approximation by truncation, i.e., by finding an optimum smoothing window (see text) for the initial conditions. The Zel'dovich approxima

Marc de Montigny

We introduce a new construction of bilinear invariant forms on Lie algebras, based on the method of graded contractions. The general method is described and the $\Bbb Z_2$-, $\Bbb Z_3$-, and $\Bbb Z_2\otimes\Bbb Z_2$-contractions are found. The results can be applied to all Lie algebras and superalgebras (finite or infinite dimensional) which admit the chose

Marco Vekic, Shao Liu, Herbert W. Hamber

A model describing Ising spins with short range interactions moving randomly in a plane is considered. In the presence of a hard core repulsion, which prevents the Ising spins from overlapping, the model is analogous to a dynamically triangulated Ising model with spins constrained to move on a flat surface. It is found that as a function of coupling strength

M. Kleinmann, R. Fritz, H. Müther, A. Ramos

The momentum dependence of the mean-field contribution to the real part of the optical model potential is investigated employing realistic nucleon-nucleon interactions. Within a non-relativistic approach a momentum dependence originates from the non-locality of the Fock exchange term. Deducing the real part of the optical model from a relativistic Dirac Brue

Andrei L. Kataev, Aleksander V. Sidorov

We present the results of our QCD analysis of the recent CCFR data for the structure function $xF_3 (x,Q^2)$ of the deep-inelastic neutrino--nucleon scattering. The analysis is based on the Jacobi polynomials expansion of the structure functions. The concrete results for the parameter $\Lambda_{\overline {MS}}^{(4)}$ and the shape of quark distributions are

G. Ramirez-Santiago, Jorge V. José

We present a detailed study of the critical properties of the 2-D XY model with maximal frustration in a square lattice. We use extensive Monte Carlo simulations to study the thermodynamics of the spin and chiral degrees of freedom, concentrating on their correlation functions. The gauge invariant spin-spin correlation functions are calculated close to the c