arXiv papers from November 1993

Sergei Lukyanov

In this paper the quantum direct scattering problem is solved for the Sine-Gordon model. Correlators of the Jost functions are derived by the angular quantization method.

William B. Kilgore

A recently published report has called into question the validity of the equivalence theorem in dynamically broken gauge theories in which the fermions making up the symmetry breaking condensate lie in an anomalous representation of the broken gauge group. Such a situation can occur if the gauge anomaly is cancelled by another sector of the theory. Using the

David W. Hogg, R. D. Blandford

A gravitational lens model of the radio quasar B1422+231 is presented which can account for the image arrangement and approximately for the relative magnifications. The locations of the principal lensing mass and a more distant secondary mass concentration were predicted and subsequently luminous galaxies were found at these locations. This argues against th

Wolfgang Bock

We discuss two proposals for a non-perturbative formulation of chiral gauge theories on the lattice. In both cases gauge symmetry is broken by the regularization. We aim at a dynamical restoration of symmetry. If the gauge symmetry breaking is not too severe this procedure could lead in the continuum limit to the desired chiral gauge theory.

Wolfgang Bock, Christoph Frick, Jan Smit, Jeroen C. Vink

We present results for the renormalized quartic self-coupling $\lm_R$ and the renormalized Yukawa coupling $y_R$ in a fermion-Higgs model with two SU(2) doublets, indicating that with the standard lattice regulator these couplings cannot become very strong.

E. Focht

Evidence for the same universal behavior of 2d Yukawa and Gross-Neveu models in a certain range of couplings, particularly for $\kappa<0$, is presented.

P. M. Harrington, A. L. Melott, S. F. Shandarin

We present in this paper a quantitative method for defining void size in large-scale structure based on percolation threshold density. Beginning with two-dimensional gravitational clustering simulations smoothed to the threshold of nonlinearity, we perform percolation analysis to determine the large scale structure. The resulting objective definition of void

Wolfgang Bock, Jan Smit, Jeroen C. Vink

We investigate a proposal for the construction of models with chiral fermions on the lattice using staggered fermions. In this approach the gauge invariance is broken by the coupling of the staggered fermions to the gauge fields. We aim at a dynamical restoration of the gauge invariance in the full quantum model. If the gauge symmetry breaking (SB) is not to

P. S. Aspinwall, B. R. Greene, D. R. Morrison

We review recent work which has significantly sharpened our geometric understanding and interpretation of the moduli space of certain $N$=2 superconformal field theories. This has resolved some important issues in mirror symmetry and has also established that string theory admits physically smooth processes which can result in a change in topology of the spa

C. Bachas, E. Kiritsis

We identify exact gauge-instanton-like solutions to (super)-string theory using the method of dimensional reduction. We find in particular the Polyakov instanton of 3d QED, and a class of generalized Yang-Mills merons. We discuss their marginal deformations, and show that for the $3d$ instanton they correspond to a dissociation of vector- and axial-magnetic

Karlo Penc, Frederic Mila

We study the phase diagram of the one dimensional (1D) $U-V$ model at quarter filling in the most general case where the on-site and first-neighbour interactions $U$ and $V$ can be both attractive and repulsive. The results have been obtained using exact diagonalization of small clusters and variational techniques, as well as exact results in various limits.

Shahn Majid

This is an introduction to work on the generalisation to quantum groups of Mackey's approach to quantisation on homogeneous spaces. We recall the bicrossproduct models of the author, which generalise the quantum double. We describe the general extension theory of Hopf algebras and the nonAbelian cohomology spaces $\CH^2(H,A)$ which classify them. They form a

Michelangelo MANGANO

We review some recent results on heavy quark production in high energy hadronic collisions. We will discuss in particular the status of production cross sections for bottom quarks and charmonium states and will present some studies on the production of bottom and charm jets, at the inclusive level and in association with electroweak gauge bosons.

Robert H. Gowdy

This paper constructs the geometrically natural objects which are associated with any projection tensor field on a manifold with any affine connection. The approaches to projection tensor fields which have been used in general relativity and related theories assume normal projection tensors of co-dimension one and connections which are metric compatible and

D. Fioravanti, G. Pradisi, A. Sagnotti

We extend to non-orientable surfaces previous work on sewing constraints in Conformal Field Theory. A new constraint, related to the real projective plane, is described and is used to illustrate the correspondence with a previous construction of open-string spectra.

D. H. Lee, X. G. Wen

We show that the Chern-Simons-Ginzburg-Landau theory of the quantum Hall effect needs a modification, because the order parameter in that theory carries an intrinsic orbital angular momentum. This quantum number contains additional information about the topological order of the Hall liquids. We propose to measure this angular momentum by circular-polarized R

Claudio Parrinello

I present some preliminary results, obtained in collaboration with C. Bernard and A. Soni, for the lattice evaluation of 2- and 3-point gluon correlation functions in momentum space, with emphasis on the amputated 3-gluon vertex function. The final goal of this approach is the study of the running QCD coupling constant as defined from the amputated 3-gluon v

A. R. Zhitnitsky

A novel class of self-dual solutions in $\sigma$ models and gauge theories is considered. The contribution of the corresponding fluctuations to the chiral condensate is calculated. We discuss the few tightly connected problems, such as the $U(1)$ problem, the $\theta$ dependence and the chiral symmetry breaking within a framework of this approach. Arguments

Bas de Bakker, Jan Smit

We look at gravitational attraction in simplicial gravity using the dynamical triangulation method. On the dynamical triangulation configurations we measure quenched propagators of a free massive scalar field. The masses measured from these propagators show that gravitational attraction is present.

Benjamin P. Lee

The diffusion-controlled reaction $kA\rightarrow\emptyset$ is known to be strongly dependent on fluctuations in dimensions $d\le d_c=2/(k-1)$. We develop a field theoretic renormalization group approach to this system which allows explicit calculation of the observables as expansions in $\epsilon^{1/(k-1)}$, where $\epsilon=d_c-d$. For the density it is foun

Edwin J. Beggs

This paper constructs exact classical solutions of the equations of QED. These are constructed in 4+2 dimensional space, which fibers over the usual 3+1 dimensional space-time. The solution is stationary and localised about a topological singularity in space time. The electromagnetic field is that of a point electric charge, positioned at the singularity. Aw

Nick Evans

Light techni-fermions and pseudo Goldstone bosons that contribute to the electroweak radiative correction parameters V,W and X may relax the constraints on technicolour models from the experimental values of the parameters S and T. Order of magnitude estimates of the contributions to V,W and X from light techni-leptons are made when the the techni-neutrino h

J. C. Caillon, J. Labarsouque

In the calculation of the $K^+$-nucleus cross sections, the coupling of the mesons exchanged between the $K^+$ and the target nucleons to the polarization of the Fermi sea has been taken into account. This polarization has been calculated in the one-loop approximation but summed up to all orders (RPA-type calculation). This effect is found to be rather impor

A. L. Melott, S. F. Shandarin, D. H. Weinberg

We quantitatively compare a particle implementation of the adhesion approximation to fully non--linear, numerical nbody simulations. Our primary tool, cross--correlation of nbody simulations with the adhesion approximation, indicates good agreement, better than that found by the same test performed with the Zel'dovich approximation (hereafter ZA). However, t

I. Pagonabarraga, J. Villain, I. Elkinani, M. B. Gordon

We study the dynamics of a stepped crystal surface during evaporation, using the classical model of Burton, Cabrera and Frank, in which the dynamics of the surface is represented as a motion of parallel, monoatomic steps. The validity of the continuum approximation treated by Frank is checked against numerical calculations and simple, qualitative arguments.

A. J. Askew, K. Golec, J. Kwiecinski, A. D. Martin

We critically examine the QCD predictions for the $Q^2$ dependence of the electron-proton deep-inelastic structure function $F_2(x,Q^2)$ in the small $x$ region, which is being probed at HERA. The standard results based on next-to-leading order Altarelli-Parisi evolution are compared with those that follow from the BFKL equation, which corresponds to the res

S. Güsken, C. Alexandrou, F. Jegerlehner, K. Schilling

A high statistics calculation, performed at $\beta =5.74,\;6.00$ and $6.26$, enables us to study the variation of the leptonic decay constants $f_P$ of heavy pseudoscalar mesons with the lattice spacing $a$. We observe only a weak $a$ dependence when the standard $\sqrt{2\kappa}$ normalization is used for the quark fields, whereas application of the Kronfeld

O. Jofre, C. Núñez

String theory in an exact plane wave background is explored. A new example of singularity in the sense of string theory for nonsingular spacetime metric is presented. The 4-tachyon scattering amplitude is constructed. The spectrum of states found from the poles in the factorization turns out to be equivalent to that of the theory in flat space-time. The mass

Y. Tanii, S. Kojima, N. Sakai

Quantum gravitational effects on the renormalization group equation are studied in the $(2+\epsilon)$-dimensional approach. Divergences in a matter one-loop effective action do not receive gravitational radiative corrections. The renormalization factor for beta functions recently found by Klebanov, Kogan and Polyakov is obtained by using the renormalized cos

A. M. Semikhatov

It is argued that singular vectors of the topological conformal (twisted $N=2$) algebra are identical with singular vectors of the $sl(2)$ Kac--Moody algebra. An arbitrary matter theory can be dressed by additional fields to make up a representation of either the $sl(2)$ current algebra or the topological conformal algebra. The relation between the two const

Jan Sladkowski

Recent development in noncommutative geometry generalization of gauge theory is reviewed. The mathematical apparatus is reduced to minimum in order to allow the non-mathematically oriented physicists to follow the development in the interesting field of research. (Lectures presented at the Silesian School of Theoretical Physics: Standard Model and Beyond'93,

Dmitri Diakonov, Maxim Polyakov, Peter Sieber, Joerg Schaldach

In this revised version we have improved the treatment of the top and bottom quark mass. This leads to slight changes of the numerical results, especially of those presented in Fig.4. The discussion of the numerical procedure and accuracy has been extended.

J. L. Alonso, Ph. Boucaud, F. Lesmes, E. Rivas

We present a calculation of the phase diagram of a $SU(2) \times SU(2)$ chiral Yukawa model with massless decoupled doublers, using a saddle point approach, both for small and large Yukawa coupling. Some preliminary MonteCarlo results are also shown.

Takao Fujita

Let B be a nef and big line bundle on a smooth complex threefold X with canonical bundle K. Let x be a point on X and suppose that BC\ge3 for any curve C passing x, B^2S\ge7 for any surface S containing x, and B^3\ge51. Then K+B is spanned at x. (Ein-Lazarsfeld proved the assertion assuming B^3\ge92.) Corollary: K+3L is spanned if L is an ample line bundle w

E. Abdalla, M. C. B. Abdalla

In this revised version we correct some mistakes, realizing the supersymmetry algebra on the exact S matrix, taking into account several phase factros. We study the constraint imposed by supersymmetry on the exact $S$-matrix of $\Complex P^{n-1}$ model, and compute a non-trivial phase factor in the relation between the $S$-matrix and one of the supersymmetry

Y. Matsubara, S. Ejiri, T. Suzuki

After making an abelian projection in the maximally abelian gauge, we measure the distribution of abelian electric flux and monopole currents around an abelian Wilson loop in $SU(2)$ and $SU(3)$ QCD. The (dual) Meissner effect is observed clearly. The vacua in the confinement phases of $SU(2)$ and $SU(3)$ are both at around the border between type-1 and type

Jaegu Kim

The gravitational and electromagnetic fields of a moving charged spinning point particle are obtained in the Lorentz covariant form by transforming the Kerr--Newman solution in Boyer--Lindquist coordinates to the one in the coordinate system which resembles the isotropic coordinates and then covariantizing it. It is shown that the general relativistic proper

F. Varadi, M. Ghil, W. M. Kaula, Keywords

The Jupiter-Saturn 2:5 near-commensurability is analyzed in a fully analytic Hamiltonian planetary theory. Computations for the Sun-Jupiter-Saturn system, extending to the third order of the masses and to the 8th degree in the eccentricities and inclinations, reveal an unexpectedly sensitive dependence of the solution on initial data and its likely nonconver

S. Shatashvili

The problems with background independence are discussed in the example of open string theory. Based on the recent proposal by Witten I calculate the String Field Theory action in conformal perturbation theory to second order and demonstrate that the proper treatment of contact terms leads to nontrivial equations of motion. I conjecture the form of the field

Henri Waelbroeck, Jose Antonio Zapata

Topological gravity is the reduction of Einstein's theory to spacetimes with vanishing curvature, but with global degrees of freedom related to the topology of the universe. We present an exact Hamiltonian lattice theory for topological gravity, which admits translations of the lattice sites as a gauge symmetry. There are additional symmetries, not present i

Mirjam Cvetic, Donam Youm

We study vacuum domain walls in a class of four-dimensional $N=1$ supergravity theories where along with the matter field, forming the wall, there is more than one ``dilaton'', each respecting $SU(1,1)$ symmetry in their sub-sector. We find {\it supersymmetric} (planar, static) walls, interpolaing between Minkowski vacuum and a new class of supersymmetric va

M. -C. Chu, J. M. Grandy, S. Huang, J. W. Negele

Cooling is used as a filter on a set of gluon fields sampling the Wilson action to selectively remove essentially all fluctuations of the gluon field except for the instantons. The close agreement between quenched lattice QCD results with cooled and uncooled configurations for vacuum correlation functions of hadronic currents and for density-density correlat

M. Bartelmann, A. Weiss

{}From the lensing properties of a numerically simulated cluster, from the statistical properties of the giant arcs produced by the cluster, and from comparing the cluster properties derived both from lensing and from the X-ray properties of the intracluster gas, we conclude (1) that clusters may be significantly more efficient for lensing than estimated fro

Jouko Mickelsson

In this talk I want to explain the operator substractions needed to renormalize gauge currents in a second quantized theory. The case of space-time dimensions $3+1$ is considered in detail. In presence of chiral fermions the renormalization effects a modification of the local commutation relations of the currents by local Schwinger terms. In $1+1$ dimensions

P. F. Kelly

The so-called Unitary Gauge Puzzle is re-examined in the light of a set of gauge dependence identities discovered by Kobes, Kunstatter and Rebhan. The ``puzzle'' is discovered to arise as an artifact of the gauge-variant and off-shell nature of the Effective Potential. An explicit analysis of the scalar sector of the Abelian Higgs model shows that the correc

V. Barger, R. J. N. Phillip, D. P. Roy

We discuss the viability of $gb \to tH \to ttb$ charged-Higgs signals at the proposed LHC $pp$ supercollider, in the decay channel $tt \to (bq \bar q')(b \ell \nu)$. Here one top quark decays hadronically and one semileptonically, with all three $b$-quarks giving flavor-tagged jets. The principal backgrounds come from $ttg,ttq,ttc$ and $ttb$ continuum produc

D. A. Buote, C. R. Canizares

(shortened for babbage) We describe (1) a new test for dark matter and alternate theories of gravitation based on the relative geometries of the X-ray and optical surface brightness distributions and an assumed form for the potential of the optical light, (2) a technique to measure the shapes of the total gravitating matter and dark matter of an ellipsoidal

Uros Seljak, Edmund Bertschinger

We use the POTENT reconstruction of the mass density field in the nearby universe to estimate the amplitude of the density fluctuation power spectrum for various cosmological models. We find sigma_8\Omega_m^{0.6}= 1.3^{+0.4}_{-0.3}, almost independently of the power spectrum. This value agrees well with the COBE normalization for the standard CDM model, whil

Z. B. Li, B. Zheng, L. Schülke

A generalized gauge invariant Ising model on random surfaces with non-trivial topology is proposed and investigated with the dual transformation. It is proved that the model is self-dual in case of a self-dual lattice. In special cases the model reduces to the known solvable Ising-type models.

K. Fujimura, K. Okano, L. Schülke, K. Yamagishi

In the numerical simulation of certain field theoretical models, the complex Langevin simulation has been believed to fail due to the violation of ergodicity. We give a detailed analysis of this problem based on a toy model with one degree of freedom ($S=-\beta\cos\theta$). We find that the failure is not due to the defect of complex Langevin simulation itse

Michio Kaku

We construct the second quantized action for sub-critical closed string field theory with zero cosmological constant in dimensions $ 2 \leq D < 26$, generalizing the non-polynomial closed string field theory action proposed by the author and the Kyoto and MIT groups for $D = 26$. The proof of gauge invariance is considerably complicated by the presence of th

Michio Kaku

(This talk was presented at the Third International Wigner Symposium on Group Theory, Oxford, September, 1993.) Matrix models provides us with the most powerful framework in which to analyze D=2 string theory, yet some of its miraculous features, such as discrete states and $w(\infty)$, remain rather obscure, because the string degrees of freedom have been r

Gabor Vattay, Andrea Harnos

We show that the daily average air humidity fluctuations exhibit non-trivial $1/f^{\alpha}$ behaviour which different from the spectral properties of other meteorological quantities. This feature and the fractal spatial strucure found in clouds make it plausible to regard air humidity fluctuations as a manifestation of self-organized criticality. We give arg

Thibault Damour, Gilles Esposito-Farese

As gravity is a long-range force, one might a priori expect the Universe's global matter distribution to select a preferred rest frame for local gravitational physics. At the post-Newtonian approximation, two parameters suffice to describe the phenomenology of preferred-frame effects. One of them has already been very tightly constrained (|alpha_2| < 4 x 10^

Boris Feigin, Edward Frenkel

A new approach to integrability of affine Toda field theories and closely related to them KdV hierarchies is proposed. The flows of a hierarchy are explicitly identified with infinitesimal action of the principal abelian subalgebra of the nilpotent part of the corresponding affine algebra on a homogeneous space. This is an extended version of the paper "Gene

Bhuvnesh Jain, Edmund Bertschinger

The Eulerian cosmological fluid equations are used to study the nonlinear mode coupling of density fluctuations. We evaluate the second-order power spectrum including all four-point contributions. In the weakly nonlinear regime we find that the dominant nonlinear contribution for realistic cosmological spectra is made by the coupling of long-wave modes and i

The High Energy Monte Carlo Grand Challenge

We report on studies of simple matrix elements from simulations with two flavors of sea quarks, both staggered and Wilson. We show the decay constants of vector and pseudoscalar mesons. The effects of sea quarks are small. These simulations are done at relatively large lattice spacing compared to most quenched studies.

P. Meszaros, M. J. Rees, H. Papathanassiou

We calculate the spectrum of blast wave models of gamma-ray burst sources, for various assumptions about the magnetic field density and the relativistic particle acceleration efficiency. For a range of physically plausible models we find that the radiation efficiency is high, and leads to nonthermal spectra with breaks at various energies comparable to those

G. Senjanovic

Spontaneous breaking of parity or time reversal invariance offers a solution to the strong CP problem, the stability of which under quantum gravitational effects provides an upper limit on the scale of symmetry breaking. Even more important, these Planck scale effects may provide a simple and natural way out of the resulting domain wall problem. (Invited tal

Urs M. Heller

The status of the triviality bound of the Higgs mass in the Minimal Standard Model is reviewed. It is emphasized that the bound is obtained, in the scalar sector, by limiting cutoff effects on physical processes. Results from several regularization schemes, including actions that allow a parameterization and tuning of the leading cutoff effects, are presente

David T. Barclay

A set of simple exactly solvable potentials are shown to have convergent WKB series. The resulting all-orders quantisation conditions provide a unified description of all known cases where an exact WKB quantisation condition has been obtained by modifying the potential with Langer-style terms, together with several new examples.

Anna Hasenfratz, Thomas A. DeGrand

Heavy dynamical fermions with masses around the cut-off do not change the low energy physics apart from a finite renormalization of the gauge coupling. In this paper we study how light the heavy fermions have to be to cause more than this trivial renormalization.

Martin Greiter

Explicit wave functions for the hierarchy of fractionally quantized Hall states are proposed, and a method for integrating out the quasiparticle coordinates in the spherical geometry is developed. Their energies and overlaps with the exact ground states for small numbers of particles with Coulomb interactions are found to be excellent. We then generalize the

Edmund Bertschinger

This article reviews the prevailing paradigm for how galaxies and larger structures formed in the universe: gravitational instability. Basic observational facts are summarized to motivate the standard cosmological framework underlying most detailed investigations of structure formation. The observed universe approaches spatial uniformity on scales larger tha

E. Shuryak

QCD point-to-point correlation functions at distances .2-1 fm are very different for different channels, and they tell us a lot about inter-quark interactions. Recent studies based on experimental data, 'instanton liquid' approach and lattice measurements are reviewed. Agreement between all of them show that instanton-induced forces dominate the light quark

J. Engels, V. K. Mitrjushkin, T. Neuhaus

We derive an analytic expression for point to point correlation functions of the Polyakov loop based on the transfer matrix formalism. The contributions from the eigenvalues of the transfer matrix including and beyond the mass gap are investigated both for the $2d$ Ising model and in finite temperature $SU(2)$ gauge theory. We find that the leading matrix el

Christoph Schweigert

We review the coset construction of conformal field theories; the emphasis is on the construction of the Hilbert spaces for these models, especially if fixed points occur. This is applied to the $N=2$ superconformal cosets constructed by Kazama and Suzuki. To calculate heterotic string spectra we reformulate the Gepner con- struction in terms of simple curre

A. V. Razumov, M. V. Saveliev

In the present paper we give a differential geometry formulation of the basic dynamical principle of the group--algebraic approach \cite{LeS92} --- the grading condition --- in terms of some holomorphic distributions on flag manifolds associated with the parabolic subgroups of a complex Lie group; and a derivation of the corresponding nonlinear integrable sy

Sadhan K. Adhikari, T. Frederico, Lauro Tomio

Starting from the two-particle Bethe-Salpeter equation in the ladder approximation and integrating over the time component of momentum, we rederive three dimensional scattering integral equations satisfying constraints of relativistic unitarity and covariance, first derived by Weinberg and by Blankenbecler and Sugar. These two-particle equations are shown to

K. Schilling, G. S. Bali

We present an extensive study on the direct determination of the running coupling alpha_s from the static quark antiquark force at short distances, in quenched QCD. We find from our high statistics potential analysis that alpha_qq exhibits two-loop asymptotic behaviour for momenta as low as .5 GeV. As a result, we determine the zero flavour Lambda-parameter

G. S. Bali, K. Schilling, C. Schlichter

First results of an ongoing high statistics study of the colour flux distribution around static quark sources in SU(2) gauge theory are presented. The flux tube profiles and widths have been investigated for several quark separations at beta=2.5 and beta=2.74. The results are tested against Michael's sum rules.

J. Layssac, F. M. Renard, G. Gounaris

Using asymptotic helicity amplitudes for Vector-Vector, Vector-Higgs and Higgs-Higgs scattering, we establish the unitarity constraints on the $SU(2)_c$ conserving and $W_\mu$ depending interactions, which at sufficiently high energies may create strong forces among the transverse vector boson and Higgs states. We then derive upper bounds for the couplings o

Manfried Faber, Harald Markum, Stefan Olejnik, Wolfgang Sakuler

We analyze the topological structure of quenched QCD in the presence of static color sources. Distributions of the topological charge density around static quarks and mesons are computed in both phases of QCD. We observe a suppression of topological fluctuations in the vicinity of external sources. In the confinement phase, the suppression occurs in the whol

Pavel Šmilauer, Dimitri D. Vvedensky

We investigate the growth kinetics on vicinal GaAs(001) surfaces by making detailed comparisons between reflection high--energy electron--diffraction specular intensity measured near in--phase diffraction conditions and the surface step density obtained from simulations of a solid--on--solid model. Only by including a barrier to interlayer transport and a sh

Clarence L. Lee

A method for determining the leading quantum contributions to the effective action for both zero and finite temperatures is presented. While it is described in the context of a scalar field theory, it can be straight-forwardly extended to include fermions. An extrapolation procedure which can significantly enhance the computational efficiency is introduced.

H. Kawabe, T. Kobayashi, N. Ohtsubo

We study a minimal string model possessing the same massless spectra as the MSSM on $Z_N\times Z_M$ orbifolds. Threshold corrections of the gauge coupling constants of SU(3), SU(2) and U(1)$_Y$ are investigated in a case of an overall modulus. Using computer analyses, we search ranges of levels of U(1)$_Y$ allowed by the LEP experiments. It is found that $Z_

QCDPAX collaboration, Y. Iwasaki, K. Kanaya, S. Sakai

We present the results for the hadron spectrum calculated on 400 configurations using point source, wall source and 8-cubic sources, in quenched QCD with Wilson fermions at $\beta=6.0$ and $K=0.155$ on a $24^3 \times 54$ lattice. The results for the ground state masses obtained with three types of quark sources agree well with each other. Masses of the first

J. Fujimoto, Y. Shimizu, T. Munehisa

A new Monte Carlo model is proposed for radiative corrections to Bhabha scattering by extending QEDPS developed for multi-photon emission in muon pair production in $e^+e^-$ annihilation. This is the QED version of the model known as parton shower in QCD. The main difference between muon pair production and Bhabha scattering is that the latter cross section

T. Onogi, S. Aoki, M. Fukugita, S. Hashimoto

We present results showing that the strong coupling constant measured in two-flavor full QCD with dynamical Kogut-Susskind quarks at $\beta=5.7$ exhibit a 15\% increase due to sea quarks over that for quenched QCD at the scale $\mu\approx 7$GeV . (talk at lattice93)

R. Chatterjee, A. Zamolodchikov

We discribe a simple way to derive spin correlation functions in 2D Ising model at critical temperature but with nonzero magnetic field at the boundary. Local magnetization (i.e. one-point function) is computed explicitly for half-plane and disk geometries.

S. Aoki, T. Umemura, M. Fukugita, N. Ishizuka

We present numerical results and their analyses of finite-size effects of hadron masses for both quenched and full QCD calculations. We show that they are much larger for full QCD due to dynamical sea quarks and the associated breaking of $Z(3)$ symmetry. We also argue that finite-size effects are non-negligible even for the largest lattice size simulation c

Ian I. Kogan

In this paper the several aspects of the $Z_{N}$ symmetry in gauge theories at high temperatures are discussed. The metastable $Z_{N}$ bubbles in the $SU(N)$ gauge theories with fermions may have, generically, unacceptable thermodynamic behavior. Their free energy $F \propto T^4$ with a positive proportionality constant. This leads not only to negative press

T. D. Palev

The observation that n pairs of para-Fermi (pF) operators generate the universal enveloping algebra of the orthogonal Lie algebra so(2n+1) is used in order to define deformed pF operators. It is shown that these operators are an alternative to the Chevalley generators. On this background Uq[so(2n+1)] and its "Cartan-Weyl" generators are written down entirely

Viacheslav V. Nikulin

This note contains preliminary calculation of topological types or real Enriques surfaces. We realize 59 topological types of real Enriques surfaces (Theorem 6) and show that all other topological types belong to the list of 21 topological types (Theorem 7). In fact, our calculation contains much more information which is probably useful to constract or proh

F. A. Bais, M. de Wild Propitius

In the Higgs phase we may be left with a residual finite symmetry group H of the condensate. The topological interactions between the magnetic- and electric excitations in these so-called discrete H gauge theories are completely described by the Hopf algebra or quantumgroup D(H). In 2+1 dimensional space time we may add a Chern-Simons term to such a model. T

S. Torres, R. Fabbri, R. Ruffini

A phenomenological power spectrum of primordial density perturbations has been constructed by using both COBE data to probe the large wavelength region, and a double power law, locally deduced from galaxy catalogs, which describes the matter correlation function up to tens of Megaparsec. The shape of the spectrum P(k) of density fluctuations exhibits a peak

Sergio Torres

Geometric characteristics of random fields are exploited to test the consistency of density perturbation model spectra with COBE data. These CMB maps are analyzed using the number of anisotropy hot spots and their boundary curvature. CMB maps which account for instrumental effects and sky coverage are Monte Carlo generated. These simulations show that a scal

Viacheslav V. Nikulin

Let X be a real projective algebraic manifold, s numerates connected components of X(R) and _2Br(X) the subgroup of elements of order 2 of the cohomological Brauer group Br(X). We study the natural homomorphism \xi : _2Br(X) \to (Z/2)^s and prove that \xi is epimorphic if H^3(X(C)/G;Z/2) \to H^3(X(R);Z/2) is injective. Here G=Gal(C/R). For an algebraic surfa

B. Enriquez

We note that a version ``with spectral parameter'' of the Drinfeld-Sokolov reduction gives a natural mapping from the KdV phase space to the group of loops with values in $\widehat N_{+}/A, \widehat N_{+}$~: affine nilpotent and $A$ principal commutative (or anisotropic Cartan) subgroup~; this mapping is connected to the conserved densities of the hierarchy.

V. V. Nikulin, R. Sujatha

Let Y be a real Enriques surface, _2Br(Y) the subgroup of elements of order 2 of Br(Y), and s, s_{or}, and s_{nor} the number of all connected, connected orientable, and connected non-orientable components of Y(R) respectively. Using universal covering K3-surface X of Y, we connect dim _2Br(Y) with the s, s_{or} and s_{nor}. As a geometric corollary of our c

V. Azcoiti, G. Di Carlo, A. Galante, A. F. Grillo

We study the phase diagram of non compact $QED_3$ using the $MFA$ method and present evidence for a continuous phase transition line at small $N_f$. We also analyze the chiral structure of the vacuum by means of the computation of the probability distribution function of the order parameter in the exact chiral limit.

V. V. Dodonov, O. V. Man'ko, V. I. Man'ko, L. Rosa

The oscillations of photon distribution function for squeezed and correlated light are shown to decrease when the temperature increases.The influence of the squeezing parameter and photon quadrature correlation coefficient on the photon distribution oscillations at nonzero temperatures is studied. The connection of deformation of Planck distribution formula

H. Aiba, T. Suzuki

We consider a model in which a collective state couples to a large number of background states. The background states can be chosen to have properties which are classically characterized as regular or chaotic. We found that the dynamical nature of the background system considerably affects some fluctuation properties of the strength function. }

Mikhail Lyubich

According to Sullivan, a space ${\cal E}$ of unimodal maps with the same combinatorics (modulo smooth conjugacy) should be treated as an infinitely-dimensional Teichm\"{u}ller space. This is a basic idea in Sullivan's approach to the Renormalization Conjecture. One of its principle ingredients is to supply ${\cal E}$ with the Teichm\"{u}ller metric. To have

Michael C. Martin, Daniel Koller, Xiaoqun Du, Peter W. Stephens

Optical measurements were performed on thin films of Rb$_{x}$C$_{60}$, identified by X-ray diffraction as mostly $x=1$ material. The samples were subjected to various heat treatments, including quenching and slow cooling from 400K. The dramatic increase in the transmission of the quenched samples, and the relaxation towards the transmission observed in slow

C. F. Baillie, A. Irback, W. Janke, D. A. Johnston

It has been suggested that the modified Steiner action functional has desirable properties for a random surface action. In this paper we investigate the scaling of the string tension and massgap in a variant of this action on dynamically triangulated random surfaces and compare the results with the gaussian plus extrinsic curvature actions that have been use

J. Smit, A. J. van der Sijs

A single magnetic monopole in pure SU(2) gauge theory is simulated on the lattice and its mass is computed in the full quantum theory. The results are relevant for our proposed realization of the dual superconductor hypothesis of confinement.

J. Smit, A. J. van der Sijs

A single magnetic monopole in pure SU(2) gauge theory is simulated on the lattice and its mass is computed in the full quantum theory. The results are relevant for our proposed realization of the dual superconductor hypothesis of confinement.

R. Kirschner

The effective action for the multi-Regge asymptotics is considered as a first step in calculating the unitarity correction to the perturbative pomeron. It can be derived from the original QCD action by intgrating out certain modes of the fields in the functional integral. The derivation is described for the case without fermions.

Henri Waelbroeck

We propose a reduced constrained Hamiltonian formalism for the exactly soluble $B \wedge F$ theory of flat connections and closed two-forms over manifolds with topology $\Sigma^3 \times (0,1)$. The reduced phase space variables are the holonomies of a flat connection for loops which form a basis of the first homotopy group $\pi_1(\Sigma^3)$, and elements of