September 1994 arXiv papers — page 6

Kiyoshi Ezawa

Chern-Simons formulation of 2+1 dimensional Einstein gravity with a negative cosmological constant is investigated when the spacetime has the topology $ R\times T^{2}$. The physical phase space is shown to be a direct product of two sub-phase spaces each of which is a non-Hausdorff manifold plus a set with nonzero codimensions. Spacetime geometrical interpre

Christopher T. Hill, Xinmin Zhang

In models of dynamical electroweak symmetry breaking which sensitively involve the third generation, such as top quark condensation, the effects of the new dynamics can show up experimentally in Z->b\bar{b}. We compare the sensitivity of Z->b\bar{b} and top quark production at the Tevatron to models of the new physics. Z->b\bar{b} is a relatively more sensit

A. Kwiatkowski, M. Steinhauser

The partial decay rate $Γ(Z\to b\bar{b})$ is significantly influenced by the mass of the top quark due to electroweak radiative corrections. The leading $\sim m_t^2$ and the next-to-leading contribution $\sim \ln m_t^2$ are known to be numerically of similar size. In this work we calculate the QCD corrections to the logarithmic correction using the heavy top

Stephen Parke

I briefly review standard top quark physics at hadron colliders and summarize the contributions to this conference. The possibility of new mechanisms for $t\bar{t}$ production are also discussed.

A. J. Buras

We calculate the QCD factors $a_1$ and $a_2$, entering the tests of factorization in non-leptonic heavy meson decays, beyond the leading logarithmic approximation in three renormalization schemes (NDR, HV, DRED). We investigate their $μ$--dependence and the renormalization scheme dependence. We point out that $a_1$ for B-decays depends very weakly on $\Lms$,

K. Geiger

A QCD based effective action is constructed to describe the dynamics of confinement and symmetry breaking in the process of parton-hadron conversion. The deconfined quark and gluon degrees of freedom of the perturbative QCD vacuum are coupled to color singlet collective fields representing the non-perturbative vacuum with broken scale and chiral symmetry. Th

Shunji Miyazaki, Yoshio Kikukawa

The fermionic part of the Schrödinger functional of QCD is formulated in the lattice regularization with the staggered fermion. The boundary condition imposed on the staggered fermion field are examined in terms of the four-component Dirac spinor. The boundary terms are different from those of the Symanzik's theory in the flavor structure due to the spec

Troy A. Schilling

This bibliography attempts to give a comprehensive overview of all the literature related to the Ashtekar variables. The original version was compiled by Peter Hübner in 1989, and it has been subsequently updated by Gabriela Gonzalez, Bernd Brügmann, and Troy Schilling. Information about additional literature, new preprints, and especially corrections are al

T. Zannias

It is shown that the only static asymptotically flat non-extrema black hole solution of the Einstein-conformally invariant scalar field equations having the scalar field bounded on the horizon, is the Schwarzschild one. Thus black holes cannot be endowed with conformal scalar hair of finite length.

Peter Huebner

A formalism and its numerical implementation is presented which allows to calculate quantities determining the spacetime structure in the large directly. This is achieved by conformal techniques by which future null infinity ($\Scri{}^+$) and future timelike infinity ($i^+$) are mapped to grid points on the numerical grid. The determination of the causal str

Frank Tzschichholz

The thesis consists of four main chapters. In Ch.2 we discuss experimental results concerning the scaling behavior and fractality of fracture surfaces. In Ch.3 continuum and discrete models for fracture mechanics are reviewed and partially extended. In Ch.4 we present numerical results for a finite size scaling of the macroscopic fracture stress in the absen

Joseph Rudnick, Robijn Bruinsma

This is a report on the derivation and application of a generalized version of the Wulff construction in two dimensions. The construction is used to find the shape of a domain containing an XY-like order parameter. In such a domain the energy per unit length of a segment of the bounding curve depends not only on the orientation of the segment, but also on th

Didier Poilblanc

The T=0 phase diagram of the planar t--J model with small doping is investigated by exact diagonalisations of square clusters with up to 32 sites. At half-filling, the single hole quasi-particule weight vanishes in the strong correlation limit $J\rightarrow 0$ while the quasi-particle mass diverges (like 1/J). However, the spectral function shows weight dist

S. Gnutzmann, U. Ritschel

In the framework of mean-field theory the equation for the order-parameter profile in a spherically-symmetric geometry at the bulk critical point reduces to an Emden-Fowler problem. We obtain analytic solutions for the surface universality class of extraordinary transitions in $d=4$ for a spherical shell, which may serve as a starting point for a pertubative

Z. -B. Li, U. Ritschel, B. Zheng

The time evolution of the three-dimensional critical Ising model relaxing from a nonequilibrium initial state is studied by means of Monte Carlo simulation. We observe the characteristic initial increase of the (spatially) averaged magnetization predicted by Janssen et al. The exponent theta' that governs the initial behavior is determined, and the depen

A. J. Schofield

An analysis of the upper critical field in the gauge model is presented. It is shown that a `strange metallic' normal state has implications for the pairing transition even if the resulting superconducting state is essentially conventional. The gauge model is considered as one example of an unconventional normal state and the optimally doped and overdope

I. Bartos, B. Rosenstein

For an electron localized near a finite rectangular step potential under strong magnetic field we found a profound local reduction of the gap between neighbouring Landau levels. We investigate under what conditions the effect persists when the barrier gets smoother. The conclusion is that to get a substantial gap reduction the barrier gradient has to be larg

V. A. Schweigert, F. M. Peeters

We present a study of the spectral properties like the energy spectrum, the eigenmodes and density of states of a classical finite system of two-dimensional (2D) charged particles which are confined by a quadratic potential. Using the method of Newton optimization we obtain the ground state and the metastable states. For a given configuration the eigenvector

Arjendu K. Pattanayak, William C. Schieve

Gaussian wavepackets are a popular tool for semiclassical analyses of classically chaotic systems. We demonstrate that they are extremely powerful in the semiquantal analysis of such systems, too, where their dynamics can be recast in an extended potential formulation. We develop Gaussian semiquantal dynamics to provide a phase space formalism and construct

D. M. Christodoulou, D. Kazanas, I. Shlosman, J. E. Tohline

A free-energy minimization approach is used to address the secular & dynamical instabilities & the bifurcations along sequences of rotating, self-gravitating fluid and stellar systems. Our approach stems from the Landau-Ginzburg theory of phase transitions. We focus on the Maclaurin sequence of oblate spheroids & on the effects of second-harmonic disturbance

Gregory D. Wirth, David C. Koo, Richard G. Kron

We present HST images of 24 confirmed members of the distant galaxy cluster Cl0016+16 at redshift 0.55. The Balmer-strong (``E+A'') and emission- line galaxies frequently show unusual visual morphology, implying that galaxian interactions produce ``active'' galaxies in moderate-redshift clusters. We use the image concentration index as a quan

Cheongho Han, Andrew Gould

We demonstrate that by making satellite-based parallax measurements of Macho events, it is possible to distinguish disk from bulge Machos and to determine individual masses of disk Machos to an accuracy of $0.2$ in the log. This is at least a 3-fold improvement over what can be done without parallaxes, i.e., just from the observed time scale of the events. I

V. Karas, A. Lanza, D. Vokrouhlicky

We have constructed general relativistic models of a stationary, axially symmnetric, Keplerian thin disk around a rotating black hole. We computed profiles of a spectral line, emitted in the inner region of the disk. In our models we have taken into account also the self-gravity of the disk. The aim of this work is to study gravitational effects on the line

W. Sutherland, C. Alcock, R. Allsman, T. Axelrod

We provide a status report on our search for dark matter in our Galaxy in the form of massive compact halo objects (MACHOs), using gravitational microlensing of background stars. This search uses a very large CCD camera on the dedicated 1.27m telescope at Mt.~Stromlo, Australia, and has been taking data for 2 years. At present, we have analysed data for 8 mi

M. Plionis, S. Borgani, L. Moscardini, P. Coles

We estimate the variance and the skewness of the cluster distribution in several dark matter (DM) models. The cluster simulations are based on the Zel'dovich approximation, the low computational cost of which allows us to run 50 random realizations of each model. We compare our results with those coming from a similar analysis of a redshift sample of Abe

T. Temesvari, C De Dominicis, I. Kondor

The problem of diagonalizing a class of complicated matrices, to be called ultrametric matrices, is investigated. These matrices appear at various stages in the description of disordered systems with many equilibrium phases by the technique of replica symmetry breaking. The residual symmetry, remaining after the breaking of permutation symmetry between repli

M. Schleif, R. Wuensch

We study the effect of center-of-mass motion and rotational corrections on hedgehog meson fields in the bosonized two-flavor Nambu \& Jona-Lasinio model. To remove the spurious motion and to restore good spin and isospin we consider a boosted and rotating soliton instead a static soliton at rest. Modified meson fields are obtained by minimizing a corrected e

B. Bergerhoff, C. Wetterich

A quantitative discussion of nonperturbative effects for the high temperature electroweak phase transition is presented. We propose a method for the computation of the temperature dependent effective scalar potential that takes into account the running of the effective gauge coupling. Compared to perturbation theory we find a moderate decrease of the critica

P. Aurenche, M. Fontannaz, J. -Ph. Guillet

We discuss the inclusive jet production at HERA in the next-to-leading logarithm approximation. Theoretical uncertainties are considered in some details. We show the importance of the jet rapidity distribution to constrain the parton densities in the photon. A comparison is made with the recent H1 data.

Stephen R. Lau

This paper investigates the relationship between the quasilocal energy of Brown and York and certain spinorial expressions for gravitational energy constructed from the Witten-Nester integral. A key feature of the Brown-York method for defining quasilocal energy is that it allows for the freedom to assign the reference point of the energy. When possible, it

Andreas Stolcke, Stephen M. Omohundro

We describe a framework for inducing probabilistic grammars from corpora of positive samples. First, samples are {\em incorporated} by adding ad-hoc rules to a working grammar; subsequently, elements of the model (such as states or nonterminals) are {\em merged} to achieve generalization and a more compact representation. The choice of what to merge and when

Shin Sasaki, Fumio Takahara

Recently, Jakobsen et al. reported that the HeII Gunn-Peterson optical depth is greater than 1.7 at $ z=3.3$. When we consider this observation combined with the HI Gunn-Peterson optical depths and the intensity of the UV background at high redshifts, we can put constraints on the spectrum of the UV background and the mass fraction of intergalactic medium. W

Michael Luke, Martin J. Savage, Mark B. Wise

We calculate the part of the order $α_s^2$ correction to the semileptonic heavy quark decay rate proportional to the number of light quark flavors, and use our result to set the scale for evaluating the strong coupling in the order $α_s$ term according to the scheme of Brodsky, Lepage and Mackenzie. Expressing the decay rate in terms of the heavy quark pole

Y. Kondo, O. Morimatsu, Y. Nishino

The pion-nucleon and kaon-nucleon scattering lengths are studied in the QCD sum rule. We show that the leading and next-to-leading order terms of the OPE give rise to the Tomozawa-Weinberg and sigma terms, respectively. We also show that in the kaon-nucleon system the $Λ(1405)$ contribution has to be subtracted from the OPE side in order to obtain the scatte

B. G. Giraud, R. Peschanski

Linear rate equations are used to describe the cascading decay of an initial heavy cluster into fragments. We consider moments of arbitrary orders of the mass multiplicity spectrum and derive scaling properties pertaining to their time evolution. We suggest that the mass weighted multiplicity is a suitable observable for the discovery of scaling. Numerical t

Ulf-G. Meißner, B. Schoch

We summarize the pertinent experimental and theoretical developments in the field of pion photo- and electroproduction in the threshold region. We discuss which experiments and which calculations should be done/performed in the future.

E. A. Gaffney

We use an auxiliary field construction to discuss the hard thermal loop effective action associated with massless thermal SU(N) QCD interacting with a weak gravitational field. It is demonstrated that the previous attempt to derive this effective action has only been partially successful and that it is presently only known to first order in the graviton coup

Tomomi Muto

We study $N=2$ supersymmetric $SU(2)/U(1)$ and $SL(2,R)/U(1)$ gauged Wess-Zumino-Witten models. It is shown that the vector gauged model is transformed to the axial gauged model by a mirror transformation. Therefore the vector gauged model and the axial gauged model are equivalent as $N=(2,2)$ superconformal field theories. In the $SL(2,R)/U(1)$ model, it is

F. W. Nijhoff, G. D. Pang

We introduce an integrable time-discretized version of the classical Calogero-Moser model, which goes to the original model in a continuum limit. This discrete model is obtained from pole solutions of a semi-discretized version of the Kadomtsev-Petviashvili equation, leading to a finite-dimensional symplectic mapping. Lax pair, symplectic structure and suffi

Kenneth Lane

Because of the top quark's very large mass, about 175~GeV, it now provides the best window into flavor physics. Thus, pair--production of top quarks at the Tevatron Collider is the most incisive probe of this physics until the Large Hadron Collider turns on in the next century. In this talk I discuss how moments of the $\ttb$ invariant mass distribution

Kenneth Lane

Precision electroweak measurements have been claimed to eliminate almost all models of technicolor. We show that the assumptions made to calculate the oblique parameters $S$,$T$,$U$ apply to QCD--like technicolor models which were ruled out long ago on much firmer grounds. These assumptions are invalid in modern ``walking'' technicolor models.

Alberto Sirlin

Using recent results of Avdeev et al. and an expansion for $μ_t/\mms$ ($M_t$ is the pole mass and $μ_t\equiv \hat{m_t}(μ_t)$ ), it is shown that when deltarho is expressed in terms of $\hat{m_t}^2(M_t)$, the QCD correction is only $(2-3)\times 10^{-3}$ in the NLO approximation. As a consequence, in terms of $M_t^2$ the correction to $\dr$ is almost entirely

Anne-Christine DAVIS, Rachel JEANNEROT

The scattering of fermions from the abelian string arising during the phase transition $SO(10) \rightarrow SU(5) \times Z_2$ induced by the Higgs in the 126 representation is studied. Elastic cross-sections and baryon number violating cross-sections due to the coupling to gauge fields in the core of the string are computed by both a first quantised method an

Pran Nath, R. Arnowitt

Event rates for dark matter detectors in neutralino--nucleus scattering are studied for supergravity unified models, including the constraint arising from the $b\rightarrow sγ$ experiment. The recent experimental measurement of this decay by the CLEO Collaboration leads to strong constraints on the SUSY particle spectrum,and also significantly affects the ev

J. M. LoSecco

The concept of studying the internal structure of mesons is explored. Mesons, which are in principle two body quark antiquark interactions, may be much easier to understand than the nucleon. Measurements of the inelastic form factors to specific final states may permit careful direct studies of various components of the strong force. For example by looking a

G. Kaelbermann, J. M. Eisenberg, Andreas Schaefer

It is well known that in lowest order the skyrmion model of the nucleon gives vanishing spin content. With new data indicating a proton spin content $ΔΣ= 0.22\pm 0.14,$ it is an increasing challenge to find ways in which the skyrmion can move away from the null result. We show here that a particular term in the skyrmion lagrangian in SU(3) involving six deri

D. Ebert, T. Feldmann, R. Friedrich, H. Reinhardt

In this letter we reconsider the previously given description of heavy mesons within a bosonized extended NJL model that combines heavy quark and chiral symmetry. In that work the naive gradient expansion of the quark determinant was used, which satisfactorily works in the light sector but does not adequately describe the heavy $(0^+,1^+)$ mesons. By investi

Andree Blotz, K. Goeke, M. Praszalowicz

The mass splittings of hyperons including the isospin splittings are calculated with $O(\ms^2)$ and $O(\ms \dm)$ accuracy respectively within the semibosonized SU(3)-NJL model. The pattern of the isospin splittings is not spoiled by the terms of the order $O(\ms \dm)$, and both splittings between the different isospin multiplets and within the same multiplet

P. Aurenche, J. -Ph. Guillet M. Fontannaz Y. Shimizu, J. Fujimoto K. Kato

We consider the production of jets in photon-photon collisions beyond the leading logarithm approximation. Theoretical uncertainties as well as uncertainties due to the virtuality of the initial photons are discussed in detail. The comparison with TOPAZ data is performed and good agreement is found between experiment and theory. It is expected that future hi

M. Kirchbach, H. Arenhoevel

The axial strange form factor $F^s_A$ of the nucleon is assumed to be dominated at low momentum transfer by the isoscalar axial vector mesons $f_1(1285)$ and $f_1(1420)$. The importance of the $a_0πN$-triangular vertex correction is demonstrated.

J. W. Bos, J. H. Koch

We study the electromagnetic form factors of a nucleon in next-to-leading order chiral perturbation theory (CPT) in the case where one of the nucleons is off its mass shell. We calculate the leading nonanalytic contributions to relevant measures for the off-shell dependence in the limited kinematical range allowed.

A. Ballestrero, E. Maina, S. Moretti

The complete matrix element for $e^+e^-\ar b\bar bW^+W^-$ has been computed at tree--level and applied to $Z^0H^0$ production followed by $Z^0\ar b\bar b$ and $H^0\ar W^+W^-$, keeping into account all irreducible backgrounds, which are dominated by \ttb production, at the Next Linear Colliders. We find that, depending on the center of mass energies and on th

R. Fleischer

Recently, flavour $SU(3)$ symmetry of strong interactions has been combined with certain dynamical assumptions to derive triangle relations among $B$-meson decay-amplitudes. We show that these relations allow a prediction of the mixing-induced CP asymmetry $\acpmi(B_d\to K^0\bar K^0)$. Contrary to statements made in several previous papers, this asymmetry sh

R. Kobayashi, M. Konuma, S. Kumano

We investigate a numerical solution of the flavor-nonsinglet Altarelli-Parisi equation with next-to-leading-order $α_s$ corrections by using Laguerre polynomials. Expanding a structure function (or a quark distribution) and a splitting function by the Laguerre polynomials, we reduce an integrodifferential equation to a summation of finite number of Laguerre

V. V. Kiselev

In a specific scheme of the QCD sum rules, one gives the estimate of $α_S\simeq 0.20$ from the data on the masses and leptonic constants of $ψ$- and $Υ$-particles.

Howard D. Trottier, R. M. Woloshyn

The effect of cooling on a number of observables is calculated in SU(2) lattice gauge theory. The static quark-antiquark potential and spin-dependent interactions are studied, and the topological charge is monitored. The chiral symmetry breaking order parameter $\langle \overlineχχ\rangle$ and meson correlators are calculated using staggered fermions. Intera

V. Azcoiti, V. Laliena, G. Di Carlo, A. Galante

The MFA approach for simulations with dynamical fermions in lattice gauge theories allows in principle to explore the parameters space of the theory (e.g. the $β, m$ plane for the study of chiral condensate in QED) without the need of computing the fermionic determinant at each point. We exploit this possibility for extracting both the renormalization group

Thomas Kalkreuter

Multigrid methods were invented for the solution of discretized partial differential equations in ordered systems. The slowness of traditional algorithms is overcome by updates on various length scales. In this article we discuss generalizations of multigrid methods for disordered systems, in particular for propagators in lattice gauge theories. A discretize

Benni Reznik

The gravitational interaction between a massive particle and a spinning particle in the weak-field limit is studied. We show that a system of a spinning point-like particle and a massive rod exhibit a topological effect analogous to the electromagnetic Aharonov-Casher effect. We discuss the effect also for systems with a cosmic string instead of a massive ro

Juan Garcia-Bellido

Contributed talk at the Seventh Marcel Grossman Meeting on Gravity, June 24-30. A theory of evolution of the universe requires both a mutation mechanism and a selection mechanism. We believe that both can be encountered in the stochastic approach to quantum cosmology. In Brans-Dicke chaotic inflation, the quantum fluctuations of Planck mass behave as mutatio

A. ~Latifi, M. ~Musette, R. ~Conte

The perturbation of an exact solution exhibits a movable transcendental essential singularity, thus proving the nonintegrability. Then, all possible exact particular solutions which may be written in closed form are isolated with the perturbative Painlevé test; this proves the inexistence of any vacuum solution other than the three known ones.

Anthony W. C. Lun, Ernest W. M. Chow

The `runaway solutions' of the Lorentz-Dirac equation of a charged particle interacting with its own field in classical electrodynamics are well-known. This type of self accelerated phenomena also exists in the solutions of the Einstein-Maxwell equations in general relativity. In particular, runaway solutions occur in a class of simple models known as th

J. C. Hicks, J. Tinka Gammel

Ground state energies and on-site density-density correlations are calculated for the 1-D Hubbard model using a linear combination of the Hubbard projection operators. The mean-field coefficients in the resulting linearized Equations of Motion (EOM) depend on both one-particle static expectation values as well as static two-particle correlations. To test the

X. G. Wu, J. K. Jain

According to the composite fermion theory, the interacting electron system at filling factor $ν$ is equivalent to the non-interacting composite fermion system at $ν^*=ν/(1-2mν)$, which in turn is related to the non-interacting electron system at $ν^*$. We show that several eigenstates of non-interacting electrons at $ν^*$ do not have any partners for interac

Herbert Schoeller, Gerd Schoen

Coulomb blockade phenomena and quantum fluctuations are studied in mesoscopic metallic tunnel junctions with high charging energies. If the resistance of the barriers is large compared to the quantum resistance, transport can be described by sequential tunneling. Here we study the influence of quantum fluctuations. They are important when the resistance is s

M. Ney-Nifle, H. J. Hilhorst

This is an analytic study of the two-dimensional XY spin glass with $\pm J$ disorder. The Hamiltonian has a continuous spin symmetry and a discrete chiral symmetry, and therefore possesses, potentially, two different order parameters and correlation lengths. The cost of breaking the symmetries is probed by comparing the ground state energy under periodic (P)

A. Latifi, M. Musette, R. Conte

The perturbation of an exact solution exhibits a movable transcendental essential singularity, thus proving the nonintegrability. Then, all possible exact particular solutions which may be written in closed form are isolated with the perturbative Painlevé test; this proves the inexistence of any vacuum solution other than the three known ones.

A. C. Quillen, Jay. A. Frogel, Jeffrey D. P. Kenney, R. W. Pogge

We present images of the barred galaxy NGC 7479 in the optical and near infrared broad--bands $B,V,R,J,H,K$, and images in H$α$+[N II] and CO(J=1$\rightarrow$0) emission. The H$α$ and CO emission in the bar are coincident and confined to narrow linear features that are offset from the center of the bar as observed in the near infrared. We estimate the gravit

A. C. Quillen, Jay. A. Frogel, Rosa A. Gonz'alez

We present near-infrared images of NGC 4314 in the $J$,$H$, and $K$ bands. Colors in these bands are constant across the bar of NGC 4314 indicating that the mass-to-light ratio is constant over much of the galaxy. We have developed an efficient procedure for mapping the gravitational potential of a non-axisymmetric galaxy based on its appearance in the near-

R. K. Schaefer, L. Piccirillo

We consider several factors concerning the design of observing strategies in Cosmic Microwave Background (CMB) anisotropy experiments. First we consider the number of independent points on the sky one should observe given a fixed observing time. Given an assumed level of sky temperature fluctuations, $σ_{sky}$ and the presence of instrumental noise $s$ in un

R. Kayser

The recent proposal by Kellermann (1993) to use the angular size/redshift relation of compact radio sources to obtain information on the value of cosmological parameters has provoked considerable discussion in the astronomical community. I present here a careful re-analysis of the angular size/redshift data of radio jets used by Kellermann (1993), using a Ko

John N. Bahcall, Sofia Kirhakos, Donald P. Schneider

Strong upper limits are placed on the visual-band brightnesses of galactic hosts for four luminous, radio-quiet quasars with redshifts between $0.16$ and~$0.24$ that were studied with the HST's Wide Field/Planetary Camera-2. Typical upper limits on the luminosities of galactic hosts are about $1.4$ mag fainter than $L^*$ for spirals and about $0.5$ mag f

A. F. Heavens, A. N. Taylor

We re-examine the effects of redshift space distortion in all-sky galaxy redshift surveys in the formalism of spherical harmonics. Within this framework we show how one can treat both the large-scale linear effects, and the small-scale nonlinear clustering, exactly to first order. The method also allows in principle a determination of the power spectrum of p

P Cook, V C Hui, C J Lambert

A new class of nano-structure devices is suggested, based on interference from the order parameter phase gradient of a single superconductor (S) in contact with a single normal metallic lead (N). By solving the Bogoliubov - de Gennes equation in two dimensions, it is demonstrated that the electrical conductance of a normal conductor of width $M$ in contact w

V. Ovsienko, C. Roger

We classify non-trivial (non-central) extensions of the group $Diff^+(S^1)$ of all diffeomorphisms of the circle preserving its orientation and of the Lie algebra $Vect (S^1)$ of vector fields on $S^1$, by the modules of tensor-densities on $S^1$. The result is: 4 non-trivial extensions of $Diff^+(S^1)$ and 7 non-trivial extensions of $Vect (S^1)$. Analogous

HongSheng Zhao, D. N. Spergel, R. M. Rich

We study a sample of 62 Baade's Window (1,-4) K giants that have published proper motions, radial velocity and metallicity. We construct the velocity ellipsoids for the metal rich stars and metal poor stars. We find a vertex deviation characteristic of a non-axisymmetric system. The long axes of the velocity ellipsoids of two samples point to two nearly perp

Alexander Turbiner

A general classification of linear differential and finite-difference operators possessing a finite-dimensional invariant subspace with a polynomial basis is given. The main result is that any operator with the above property must have a representation as a polynomial element of the universal enveloping algebra of the algebra of differential (difference) ope

I. V. Musatov, V. A. Nikolaev, E. Sorace, M. Tarlini

We consider the quantization of chiral solitons with baryon number $B>1$. Classical solitons are obtained within the framework of a variational approach. From the form of the soliton solution it can be seen that besides the group of symmetry describing transformations of the configuration as a whole there are additional symmetries corresponding to internal t

Murray Gerstenhaber, Alexander A. Voronov

This paper emphasizes the ubiquitous role of moduli spaces of algebraic curves in associative algebra and algebraic topology. The main results are: (1) the space of an operad with multiplication is a homotopy Gerstenhaber (i.e., homotopy graded Poisson) algebra; (2) the singular cochain complex is naturally an operad; (3) the operad of decorated moduli space

John Cardy

We consider the probability $P(t)$ that a given site remains unvisited by any of a set of random walkers in $d$ dimensions undergoing the reaction $A+A\to0$ when they meet. We find that asymptotically $P(t)\sim t^{-θ}$ with a universal exponent $θ=\ffrac12-O(ε)$ for $d=2-ε$, while, for $d>2$, $θ$ is non-universal and depends on the reaction rate. The analysi

P. A. Henning, R. Sollacher, H. Weigert

In principle every excitation acquires a finite lifetime in a hot system. This nonzero spectral width is calculated self-consistently for massive fermions coupled to massless scalar, vector and pseudoscalar bosons. It is shown that the self-consistent summation of the corresponding Fock diagram for fermions eliminates all infrared divergences although the bo

Clifford V. Johnson

A description is given of how to construct (0,2) supersymmetric conformal field theories as coset models. These models may be used as non-trivial backgrounds for Heterotic String Theory. They are realised as a combination of an anomalously gauged Wess-Zumino-Witten model, right-moving supersymmetric fermions, and left-moving current algebra fermions. Requiri

David R. Masson

A contiguous relation for complementry pairs of very well poised balanced ${}_{10}ϕ_9$ basic hypergeometric functions is used to derive an explict expression for the associated continued fraction. This generalizes the continued fraction results associated with both Ramanujan's Entry 40 and Askey-Wilson polynomials which can be recovered as limits. Associ

A. Shafei Deh Abad, V. Milani

In this paper which is the completion of [1], we construct the $A_0(q)$-algebra of $Q$-meromorphic functions on the quantum plane. This is the largest non-commutative, associative, $A_0(q)$-algebra of functions constructed on the quantum plane. We also define the notion of quantum subsets of R$^2$ which is a generalization of the notion of quantum disc and c

W. Lerche, N. P. Warner

We investigate how specific free-field realizations of twisted N=2 supersymmetric coset models give rise to natural extensions of the ``matter'' Hilbert spaces in such a manner as to incorporate the various gravitational excitations. In particular, we show that adopting a particular screening prescription is equivalent to imposing the requisite equiv

C. Kristjansen

We introduce a parametrization of the coupling constant space of the generalized Kontsevich models in terms of a set of moments equivalent to those introduced recently in the context of topological gravity. For the simplest generalization of the Kontsevich model we express the moments as elementary functions of the susceptibilities and the eigenvalues of the

C. Duval, V. Ovsienko

The space of linear differential operators on a smooth manifold $M$ has a natural one-parameter family of $Diff(M)$ (and $Vect(M)$)-module structures, defined by their action on the space of tensor-densities. It is shown that, in the case of second order differential operators, the $Vect(M)$-module structures are equivalent for any degree of tensor-densities

Igor R. Klebanov, Akikazu Hashimoto

We present a non-perturbative solution of large $N$ matrix models modified by terms of the form $ g(\TrΦ^4)^2$, which add microscopic wormholes to the random surface geometry. For $g<g_t$ the sum over surfaces is in the same universality class as the $g=0$ theory, and the string susceptibility exponent is reproduced by the conventional Liouville interaction

Eric Braaten

Most previous calculations of the annihilation decay rates of heavy quarkonium were based on factorization assumptions that were unproven and, in some cases, even incorrect. The recent development of a general factorization formula for heavy quarkonium annihilation rates has provided a rigorous theoretical foundation for such calculations. The factorization

K. S. Babu, S. M. Barr

In the context of supersymmetric $SO(10)$ grand unified models, it is shown that the gauge symmetry breaking as well as a natural doublet--triplet splitting can be achieved with a minimal Higgs system consisting of a single adjoint and a pair of vector and spinor multiplets. Such a Higgs spectrum has been shown to arise in the free fermionic formulation of s

Tanmoy Bhattacharya, Rajan Gupta

We present results for semi-leptonic form-factors obtained on a statistical sample of $66$ $32^3 \times 64$ lattices at $β= 6.0$ using quenched Wilson fermions. We find $f_+^{D \to K l ν}(q^2 = 0) = 0.73 \pm 0.06$, $A_2/A_1({D \to K^* l ν}) = 0.72 \pm 0.22$, $V/A_1({D_s \to ϕl ν}) = 1.91 \pm 0.04$, and $A_2/A_1({D_s \to ϕl ν}) = 0.68 \pm 0.09$, where the err

J. Milana, S. Nussinov

We discuss experimental signatures capable of nearly immediate study that would discern/constrain new physics manifested via enhanced gluonic penguin decays of the $b$.

Robert Brandenberger, Anne-Christine Davis, Tomislav Prokopec, Mark Trodden

We consider the effects of particle transport in the topological defect-mediated electroweak baryogenesis scenarios of Ref. 1. We analyze the cases of both thin and thick defects and demonstrate an enhancement of the original mechanism in both cases due to an increased effective volume in which baryogenesis occurs. This phenomenon is a result of imperfect ca

Dieter Stoll

For the sake of eliminating gauge variant degrees of freedom we discuss the way to introduce angular variables in the hamiltonian formulation of QCD. On the basis of an analysis of Gauss&#39; law constraints a particular choice is made for the variable transformation from gauge fields to angular field variables. The resulting formulation is analogous to the

Dieter Stoll, Soh Takeuchi, Koichi Yazaki

We analyse the mechanism in which zero modes lead to an elimination of fermionic color non--singlet states in 1+1 dimensions. Using a hamiltonian lattice formulation we clarify the physical meaning of the zero modes but we do not find support for speculations on the crucial importance of lower dimensional fields (zero modes in 1+1 dimension) for the infrared

Tao Huang, Chuan-Wang Luo

We present an investigation on the ligh flavor dependence of the Isgur-Wise function for $B_a\rightarrow D_a$ and $B_a\rightarrow D^{*}_a$ in the framework of QCD sum rules. It is found that the Isgur-Wise function for $B_s$ decay falls faster than that for $B_{u,d}$ decay , which is just contrary to the recent prediction of the heavy meson chiral perturbati

Colin Morningstar, Marvin Weinstein

The COntractor REnormalization group (CORE) approximation, a new method for solving Hamiltonian lattice systems, is introduced. The approach combines variational and contraction techniques with the real-space renormalization group approach and is systematically improvable. Since it applies to lattice systems of infinite extent, the method is suitable for stu

Hadi Salehi

It is argued that a characteristic length may be associated with the entropic state of a spherically symmetric black hole in the cosmological context. This length is much smaller than the Schwarzschild-radius of a black hole and may act as a regulator of arbitrarily high frequencies apparently entering the usual derivation of Hawking&#39;s radiation.

Joseph Katz, Yasunari Okuta

Most spherical thin shells, enclosing black body radiation satisfy the dominant energy condition if they have at least $\simeq 30\%$ of the total mass-energy. Containers with less mass energy, able to sustain high pressures, contain mostly unstable radiation. If they have negligible mass energy they are unable to sustain the pressures and the radiation is un

Junwu Gan

An asymptotically exact solution is presented for the two-impurity Kondo model for a finite region of the parameter space surrounding the critical point. This region is located in the most interesting intermediate regime where RKKY interaction is comparable to the Kondo temperature. After several exact simplifications involving reduction to one dimension and