July 1993 arXiv papers — page 3

H. Hiro-Oka, H. Minakata

We present a large-$N$ collective field formalism for anyons in external magnetic fields interacting with arbitrary two-body potential. We discuss how the Landau level is reproduced in our framework. We apply it to the soluble model for anyons proposed by Girvin et al., and obtain the dispersion relation of collective modes for arbitrary statistical paramete

Toshiki Nakashima

We study the algebra $B_q(\ge)$ presented by Kashiwara and introduce intertwiners similar to $q$-vertex operators. We show that a matrix determined by 2-point functions of the intertwiners coincides with a quantum R-matrix (up to a diagonal matrix) and give the commutation relations of the intertwiners. We also introduce an analogue of the universal R-matrix

Howard D. Trottier

A factorization theorem for $P$-wave quarkonium production, recently derived by Bodwin, Braaten, Yuan and Lepage, is applied to $Υ\to χ_{cJ} + X$, where $χ_{cJ}$ labels the ${}^3 P_J$ charmonium states. The widths for $χ_{cJ}$ production through color-singlet $P$-wave and color-octet $S$-wave $c \bar c$ subprocesses are computed each to leading order in $α_s

S. M. Bilenky, C. Giunti, V. Wataghin

The process $ \bar{p} p \rightarrow e^{-} e^{+} $ is considered in the general case of polarized initial particles. A relation between the difference of the phases of the electromagnetic form factors $G_M$ and $G_E$ in the time-like region and measurable asymmetries is derived. It is shown that the moduli of the form factors can be determined from measuremen

M. Drees, R. M. Godbole

We update our previous calculation of di--jet production in two--photon collisions at future \ee\ colliders, including both beam-- and bremsstrahlung. We then discuss the production of heavy ($c,b,t$) quarks. Our study re--confirms that colliders with much beamstrahlung offer no physics advantages over designs with little beamstrahlung.

Tadashi Kon, Tetsuro Kobayashi, Shoichi Kitamura, Keiichiro Nakamura

In the framework of the minimal supersymmetric standard model (MSSM) and the R-parity breaking model (RBM), we investigate production processes of the scalar top (stop) at HERA energies. These models are characterized by the possible existence of the light stop whose mass is lighter than those of the top quark and the other squarks. It is shown that in the M

R. B. Mann, M. S. Morris

We look at the program of modelling a subatomic particle---one having mass, charge, and angular momentum---as an interior solution joined to a classical general-relativistic Kerr-Newman exterior spacetime. We find that the assumption of stationarity upon which the validity of the Kerr-Newman exterior solution depends is in fact violated quantum mechanically

Antonio Campos, Enric Verdaguer

The in-in effective action formalism is used to derive the semiclassical correction to Einstein's equations due to a massless scalar quantum field conformally coupled to small gravitational perturbations in spatially flat cosmological models. The vacuum expectation value of the stress tensor of the quantum field is directly derived from the renormalized

Gerhard Post, Alexander Turbiner

A complete classification of linear differential operators possessing finite-dimensional invariant subspace with a basis of monomials is presented.

D. Hone, M. Holthaus

We develop a formalism to study the role of local defects in tight binding systems in the presence of a strong external ac electric field. It is found that the appearance and disappearance of localized states, as well as their localization lengths, can be controlled by the amplitude or frequency of the driving field. The theory is illustrated by numerical mo

M. C. Chang, Q. Niu

The local density of states ρ(x,E) is calculated for a Bloch electron in an electric field. Depending on the system size, we can see one or more sequences of Wannier-Stark ladders in ρ(x,E), with Lorentz type level widths and apparent spatial localization of the states. Our model is a chain of delta function potential barriers plus a step-like electric poten

Steven H. Simon, Bertrand I. Halperin

A fractional quantized Hall state with filling fraction $ν= p/(2mp+1)$ can be modeled as an integer quantized Hall state of transformed fermions, interacting with a Chern-Simons field. The electromagnetic response function for these states at arbitrary frequency and wavevector can be calculated using a semiclassical approximation or the Random Phase Approxim

D. C. Koo, C. Gronwall, G. Bruzual

We adopt a new approach to explore the puzzling nature of faint blue field galaxies. Instead of assuming that the local luminosity function is well defined, we first determine whether any non-evolving set of luminosity functions for different spectral types of galaxies is compatible with the observed marginal distributions in optical and near-infrared counts

Elisa Prato, Siye Wu

We prove a ðtype formula in a suitable non-compact setting. We use this formula to evaluate explicitly the pushforward of the Liouville measure via the moment map of both an abelian and a non-abelian group action. As an application we obtain the classical analogues of well-known multiplicity formulas for the holomorphic discrete series representations.

G. K. Leontaris

Constraints from flavour changing neutral currents are discussed in the context of predictive Grand Unified Supersymmetric Theories. Uncertainties in the estimation of their amplitudes are minimized by using a successful mass matrix ansatz which predicts the arbitrary parameters of the Standard Model. Furthermore, Renormalization Group Equations are used in

Ya. P. Pugay

We represent Feigin's construction [22] of lattice W algebras and give some simple results: lattice Virasoro and $W_3$ algebras. For simplest case $g=sl(2)$ we introduce whole $U_q(sl(2))$ quantum group on this lattice. We find simplest two-dimensional module as well as exchange relations and define lattice Virasoro algebra as algebra of invariants of $U

Y. Koike

The QCD sum rule method is applied to derive a formula for the rho, omega, phi meson-nucleon spin-isospin-averaged scattering lengths $a_{ρ,ω,ϕ}$. We found that the crucial matrix elements are $\langle\bar{q}γ_μD_νq\rangle_N$ ($q=u,d$) (twist-2 nucleon matrix element) for $a_{ρ,ω}$ and $m_s\langle\bar{s}s\rangle_N$ for $a_ϕ$, and obtained $a_ρ=0.14\pm 0.07$

Ekkard Schnedermann, Josef Sollfrank, Ulrich Heinz

We develop a complete and consistent description for the hadron spectra from heavy ion collisions in terms of a few collective variables, in particular temperature, longitudinal and transverse flow. To achieve a meaningful comparison with presently available data, we also include the resonance decays into our picture. To disentangle the influences of transve

Walter Gautschi

When integrating functions that have poles outside the interval of integration, but are regular otherwise, it is suggested that the quadrature rule in question ought to integrate exactly not only polynomials (if any), but also suitable rational functions. The latter are to be chosen so as to match the most important poles of the integrand. We describe two me

Makoto Idzumi

Exact integral representations of spin one-point functions (ground state expectation values) are reported for the spin-1 analog of the XXZ model in the region $-1<q<0$. The method enables one to calculate arbitrary $n$-point functions in principle. We also report a construction of level 2 irreducible highest weight representations of $U_q(\hat{sl}_2)$ in ter

Yannick Meurice

We propose a perturbative improvement of the hierarchical approximation for gaussian models. The procedure is based on a relabeling of the momenta which allows one to express the symmetries of the hierarchical model using a simple multiplication group. The representations of this group are used to expand the action. The perturbative expansion is treated as a

Walter Troost, Antoine Van Proeyen

We summarize the application of the field--antifield formalism to the quantization of gauge field theories. After the gauge fixing, the main issues are the regularization and anomalies. We illustrate this for chiral $W_3$ gravity. We discuss also gauge theories with a non-local action, induced by a matter system with an anomaly. As an illustration we use ind

D. Johnston

We write down matrix models for Ising spins with zero external field on the vertices of dynamical triangulated random surfaces (DTRS) and dynamically quadrangulated random surfaces (DQRS) and compare these with the standard matrix model approach which places the spins on the dual $ϕ^3$ and $ϕ^4$ graphs. We show that the critical temperatures calculated in th

Dirk Graudenz

Jet cross sections in deeply inelastic scattering in the case of transverse photon exchange for the production of (1+1) and (2+1) jets are calculated in next-to-leading order QCD (here the `+1&#39; stands for the target remnant jet, which is included in the jet definition for reasons that will become clear in the main text). The jet definition scheme is base

Benjamin Grinstein, Yosef Nir, Joao M. Soares

A recent study by Randall and Sundrum shows that models of Extended Technicolor (ETC) have interesting implications on rare B decays. We extend their study to the decay B -> mu+ mu- X. ETC models with a GIM mechanism predict a decay rate that is a factor of order 30 above the Standard Model, violating the experimental upper bound by a factor of 2-4. ``Tradit

Graciela Gelmini

These are three lectures given at the ``Lake Louise Winter Institute&#34;, (Lake Louise Canada, Feb 1993). A pedagogical introduction is given to attempts to formulate a more fundamental theory of elementary particles than that provided by the standard model. After a review of the basic elements of the standard model, its unsatisfactory features, and ideas t

W. Kilian, T. Mannel

The construction of heavy quark effective field theory (HqEFT) is extended to arbitrary order in both expansion parameters $α_s$ and $1/m_q$. Matching conditions are discussed for the general case, and it is verified that this approach correctly reproduces the infrared behaviour of full QCD. Choosing a renormalization scheme in the full theory fixes the reno

A. D. Jackson, T. Wettig, N. L. Balazs

A simple lattice gas model in one dimension is constructed in which each site can be occupied by at most one particle of any one of $D$ species. Particles interact with a randomly drawn nearest neighbor interaction. This model is capable of reproducing the factorial moments observed in high--energy scattering. In the limit $D \rightarrow \infty$, the factori

Chuichiro Hattori, Masahisa Matsuda, Takeo Matsuoka, Daizo Mochinaga

In the superstring models we have not only the complete {\bf 27} multiplets of $E_6$ but also extra incomplete $({\bf 27}+{\overline {\bf 27}})$ chiral supermultiplets being alive at low energies. Associated with these additional multiplets, when the gauge symmetry contains more than one $U(1)$ gauge group, there may exist gauge kinetic mixings among these $

Pevrez Hoodbhoy, Xiangdong Xi

The twist-four quark and gluon distributions in a transversely polarized nucleon are identified and relations among them are discussed by using QCD equations of motion. Their contribution, at the order of ${\cal O} \left( 1/Q^2 \right)$, to the Drell-Yan cross section in transversely polarized nucleon-nucleon collisions is calculated.

Xiangdong Ji

I discuss a few interpolating sum rules for spin structure functions of the nucleon. Using the concept of duality, I argue that the $G_1$ sum rule, including the elastic contribution, is useful for learning higher twist matrix elements of the nucleon.

Robert Garisto, John N. Ng

Supersymmetric (SUSY) theories are often thought to give large branching ratios for $b \rightarrow s γ$ from charged Higgs loops. We show that in many cases chargino loop contributions can cancel those of the Higgs, and SUSY can give $B(b \rightarrow s γ)$ at or below the \SM\ prediction. We show this occurs because the large stop mass splittings usually fou

J. Gegenberg, G. Kunstatter

It is well known that one can parameterize 2-D Riemannian structures by conformal transformations and diffeomorphisms of fiducial constant curvature geometries; and that this construction has a natural setting in general relativity theory in 2-D. I will show that a similar parameterization exists for 3-D Riemannian structures, with the conformal transformati

M. Gasperini, M. Giovannini

The entropy growth in a cosmological process of pair production is completely determined by the associated squeezing parameter, and is insensitive to the number of particles in the initial state. The total produced entropy may represent a significant fraction of the entropy stored today in the cosmic black-body radiation, provided pair production originates

Alan T. Dorsey

The dynamics of an interface between the normal and superconducting phases under nonstationary external conditions is studied within the framework of the time-dependent Ginzburg-Landau equations of superconductivity, modified to include thermal fluctuations. An equation of motion for the interface is derived in two steps. First, the method of matched asympto

P Nisamaneephong, L. Zhang, M. Ma

We show that gaussian quantum fluctuations, even if infinitesimal, are sufficient to destroy the superfluidity of a disordered boson system in 1D and 2D. The critical disorder is thus finite no matter how small the repulsion is between particles. Within the gaussian approximation, we study the nature of the elementary excitations, including their density of

B. Bonnier, M. Hontebeyrie, Y. Leroyer, C. Meyers

We study the deposition of line segments on a two-dimensional square lattice. The estimates for the coverage at jamming obtained by Monte-Carlo simulations and by $7^{th}$-order time-series expansion are successfully compared. The non-trivial limit of adsorption of infinitely long segments is studied, and the lattice coverage is consistently obtained using t

Peter Kopietz

Using an analogy between the conductivity tensor of electronic systems and the spin stiffness tensor of spin systems, we introduce the concept of the Thouless number $g_0$ and the dimensionless frequency dependent conductance $g( ω)$ for quantum spin models. It is shown that spin diffusion implies the vanishing of the Drude peak of $g ( ω)$, and that the spi

John Ringland, Charles Tresser

We generate all the finite kneading sequences of one of the two kinds of bimodal map on the interval, building each sequence uniquely from a pair of shorter ones. There is a single pair at generation 0, with members of length 1. Concomitant with this genealogy of kneading sequences is a unified genealogy of all the periodic orbits. (6/93)

Siegfried Grossmann, Detlef Lohse

The fractal dimension $δ_g^{(1)}$ of turbulent passive scalar signals is calculated from the fluid dynamical equation. $δ_g^{(1)}$ depends on the scale. For small Prandtl (or Schmidt) number $Pr<10^{-2}$ one gets two ranges, $δ_g^{(1)}=1$ for small scale r and $δ_g^{(1)}$=5/3 for large r, both as expected. But for large $Pr> 1$ one gets a third, intermediate

A. H. Bougourzi, Robert A. Weston

We extend the recent approach of M. Jimbo, K. Miki, T. Miwa, and A. Nakayashiki to derive an integral formula for the N-point correlation functions of arbitrary local operators of the antiferromagnetic spin-1 XXZ model. For this, we realize the quantum affine symmetry algebra $U_q(su(2)_2)$ of level 2 and its corresponding type I vertex operators in terms of

Miao Li

Strings propagating along surfaces with Dirichlet boundaries are studied in this paper. Such strings were originally proposed as a possible candidate for the QCD string. Our approach is different from previous ones and is simple and general enough, with which basic problems can be easily addressed. The Green function on a surface with Dirichlet boundaries is

M. Cvetic, A. A. Tseytlin

We find charged, abelian, spherically symmetric solutions (in flat space-time) corresponding to the effective action of $D=4$ heterotic string theory with scale-dependent dilaton $\p$ and modulus $\vp$ fields. We take into account perturbative (genus-one), moduli-dependent `threshold&#39; corrections to the coupling function $f(\p,\vp)$ in the gauge field ki

D. V. Ahluwalia, T. Goldman, M. B. Johnson

We present a formalism that extends the Majorana-construction to arbitrary spin (j,0)+(0,j) representation spaces. For the example case of spin-1, a wave equation satisfied by the Majorana-like (1,0)+(0,1) spinors is constructed and its physical content explored. The (j,0)+(0,j) Majorana-construct is found to possess an unusual classical and quantum field th

V. Buchholtz, T. Pöschel

We report on a lattice based algorithm, completely vectorized for molecular dynamics simulations. Its algorithmic complexity is of the order $O(N)$, where $N$ is the number of particles. The algorithm works very effectively when the particles have short range interaction, but it is applicable to each kind of interaction. The code was tested on a Cray ymp el

Saburo Higuchi, Chigak Itoi, Shinsuke Nishigaki, Norisuke Sakai

An exact renormalization group equation is derived for the free energy of matrix models. The renormalization group equation turns out to be nonlinear for matrix models, as opposed to linear for vector models. An algorithm for determining the critical coupling constant and the critical exponent is obtained. As concrete examples, one-matrix models with one and

James. W. York,

A deeper understanding of the thermal properties of black holes than we presently have depends to a large degree on obtaining a firmer grasp of the properties of the entropy. For such an understanding we must at least know the basic relations among entropy, energy, and temperature of a black hole in thermal equilibrium with quantized matter fields. Limiting

T. Kimura, J. Stasheff, A. A. Voronov

Recent algebraic structures of string theory, including homotopy Lie algebras, gravity algebras and Batalin-Vilkovisky algebras, are deduced from the topology of the moduli spaces of punctured Riemann spheres. The principal reason for these structures to appear is as simple as the following. A conformal field theory is an algebra over the operad of punctured

Ken Kiers, Nathan Weiss

Mean Field Theory has been extensively used in the study of systems of anyons in two spatial dimensions. In this paper we study the physical grounds for the validity of this approximation by considering the Quantum Mechanical scattering of a charged particle from a two dimensional array of magnetic flux tubes. The flux tubes are arranged on a regular lattice

John Schwarz

The heterotic string theory, compactified to four dimensions, has been conjectured to have a duality symmetry (S duality) that transforms the dilaton nonlinearly. If valid, this symmetry could provide an important means of obtaining information about nonperturbative features of the theory. Even though it is inherently nonperturbative, S duality exhibits many

Mark Wexler

Recently, the free energy of the target space mean field (TSMF) matrix model has been calculated in the low temperature phase, order-by-order in a low temperature expansion. The TSMF model is a matrix model whose discrete target space has an infinite coordination number, and whose free energy assumes a universal form, corresponding to baby universes joined i

J. Barcelos-Neto, Sasanka Ghosh, Shibaji Roy

We consider the even parity superLax operator for the supersymmetric KP hierarchy of the form $L~=~D^2 + \sum_{i=0}^\infty u_{i-2} D^{-i+1}$ and obtain the two Hamiltonian structures following the standard method of Gelfand and Dikii. We observe that the first Hamiltonian structure is local and linear whereas the second Hamiltonian structure is non-local and

P V Landshoff, P van Nieuwenhuizen

We give a unified derivation of the propagator in the gauges $n.A=0$ for $n^2$ timelike, spacelike or lightlike. We discuss the physical states and other physical questions.

T. Nakatsu, A. Kato, M. Noumi, T. Takebe

We study the relation between topological string theory and singularity theory using the partition function of $A_{N-1}$ topological string defined by matrix integral of Kontsevich type. Genus expansion of the free energy is considered, and the genus $g=0$ contribution is shown to be described by a special solution of $N$-reduced dispersionless KP system. We

Hiroshi Yamamoto, Akihisa Hayashi, Takaaki Hashimoto, Minoru Horibe

It is shown that the difficulties in formulating the quantum field theory on discrete spacetime appear already in classical dynamics of one degree of freedom on discrete time. The difference equation of motion which maintains a conserved quantity like energy has a very restricted form that is not probably derived by the least action principle. On the other h

U. Baur

The recent CLEO results on on radiative $b$-quark decays are used to derive constraints on anomalous $WWγ$ couplings. These constraints are compared with expectations from $p\bar p\rightarrow e^\pm p\llap/_Tγ+X$ at the Tevatron. The usefulness of exclusive radiative $B$ meson decay channels in probing the $WWγ$ vertex is largely limited by present theoretica

C. S. Kim, S. M. Kim, M. G. Olsson

Quark masses are shown to play an important role in the nucleon sea. Our analysis using massive QCD splitting functions demonstrates the existence of two Feynman-$x$ sea regimes. For small $x$ the strange sea is larger while at large $x$ the non-strange light sea is dominant. This crossover effect has been observed in a phenomenological analysis by the CTEQ

E. C. Christova, M. Fabbrichesi

We find that the $CP$-violating asymmetry $$ \frac{Γ\left(t \rightarrow bW^+ \right) - Γ\left(\bar{t} \rightarrow \bar{b}W^- \right)} {Γ\left(t \rightarrow bW^+ \right) + Γ\left(\bar{t} \rightarrow \bar{b}W^- \right)} $$ at the one-loop order within the minimal supersymmetric extension of the standard model is of the order of few per cent for maximal $CP$ vi

Paulo Bedaque, Ashok Das

We study the dynamics of a second order phase transition in a situation thatmimics a sudden quench to a temperature below the critical temperature in a model with dynamical symmetry breaking. In particular we show that the domains of correlated values of the condensate grow as $\sqrt{t}$ and that this result seems to be largely model independent.

P. Bedaque, A. Das, V. S. Mathur

Two-body nonleptonic decays of charmed mesons are studied on the basis of a simple pole-dominance model involving the vector, pseudoscalar and axial-vector meson poles.

J. Bernabeu, J. Korner, A. Pilaftsis, K. Schilcher

We analyze the possibility of universality violation in diagonal leptonic decays of the $Z$ boson, in the context of interfamily &#34;see-saw&#34; models. In a minimal extension of the Standard Model with right-handed neutrino fields, we find that universality-breaking effects increase quadratically with the heavy Majorana neutrino mass and may be observed i

E. A. Dudas

The spontaneous breakdown of the scale, the chiral and the superconformal symmetries for a hidden $SU(N)$ gauge group is studied in an effective lagrangean approach. The relevant low-energy degrees of freedom are taken to be the composite Goldstone particles associated with these three broken symmetries. Supersymmetry is spontaneously broken in the large $N$

Fabio Zwirner

Summary Talk of the Workshop `Properties of SUSY particles&#39; Erice, September 28 -- October 4, 1992.

Takahiro Kubota, Takeshi Kurimoto, Eiichi Takasugi

An intriguing possibility is explored that the solar neutrino data could be used as a probe to the magnetic field structure in the sun. Various cyclic phenomena occurring on the surface of the sun have been accounted for by the so-called dynamo-mechanism. According to this, a self-generating mechanism of solar cyclic activities gives rise to twisting toroida

Adam D. Helfer

The energy--momentum radiated in gravitational waves by an isolated source is given by a formula of Bondi. This formula is highly non--local: the energy--momentum is not given as the integral of a well--defined local density. It has therefore been unclear whether the Bondi formula can be used to get information from gravity--wave measurements. In this note,

R. K. Bhaduri, Shuxi Li, Kaori Tanakaa, J. C. Waddington

A two-dimensional harmonic oscillator, when rotated by the oscillator frequency, generates Landau-like levels. A further cranking results in condensates and gaps resembling the fractional quantum Hall effect. For a filling fraction $ν=p/q$, with $q$ odd, the model predicts that the gap is proportional to $\sqrt{n_{e}/pq}$, where $n_{e}$ is the electron densi

L. P. Gor&#39;kov, V. Nikos Nicopoulos, Pradeep Kumar

We study how doping destroys the AF order in the layered cuprates within the framework of the charge--transfer insulator concept. We use the criterion of stability of the AF background to show that the stability problem is one of the main issues in any correspondence between results for the $t-J$ model and, say, the three--band model for the lightly--doped l

K. G. Singh, D. S. Rokhsar

The disordered Bose Hubbard model is studied numerically within the Bogoliubov approximation. First, the spatially varying condensate wavefunction in the presence of disorder is found by solving a nonlinear Schrodinger equation. Using the Bogoliubov approximation to find the excitations above this condensate, we calculate the condensate fraction, superfluid

A. Jagannathan

We study electronic properties as a function of the six types of local environments found in the octagonal tiling. The density of states has six characteristic forms, although the detailed structure differs from site to site since no two sites are equivalent in a quasiperiodic tiling. We present the site-dependent magnetic susceptibility of electrons on this

Atanas Groshev

We derive an empirical formula for the width of quantum Hall effect plateaus which is free of adjustable parameters. It describes the integer, fractional and $ν= 0$ (Wigner insulator) quantum Hall effect in single heterojunctions. The temperature scale of the existence of these three phenomena is the same as the melting temperature of a classical Wigner crys

Florian Gebhard, Andreas Girndt

We study Hartree-Fock, Gutzwiller, Baeriswyl, and combined Gutzwiller-Baeriswyl wave functions for the exactly solvable one-dimensional $1/r$-Hubbard model. We find that none of these variational wave functions is able to correctly reproduce the physics of the metal-to-insulator transition which occurs in the model for half-filled bands when the interaction

Peter Frick, Erik Aurell

We consider a class of shell models of 2D-turbulence. They conserve inertially the analogues of energy and enstrophy, two quadratic forms in the shell amplitudes. Inertially conserving two quadratic integrals leads to two spectral ranges. We study in detail the one characterized by a forward cascade of enstrophy and spectrum close to Kraichnan&#39;s $k^{-3}$

Atsushi Moriwaki

Let f : X --> Spec(Z) be an arithmetic variety of dimension d >= 2 and (H, k) an arithmetically ample Hermitian line bundle on X. Let (E, h) be a rank r vector bundle on X. In this paper, we will prove that if E is semistable with respect to H on each connected component of the infinite fiber of X, then { c_2(E, h) - (r-1)/(2r) c_1(E, h)^2 } c_1(H, k)^{d-2}

V. Buchholtz, T. Poeschel

We report on a lattice based algorithm, completely vectorized for molecular dynamics simulations. Its algorithmic complexity is of the order O(N), where $N$ is the number of particles. The algorithm works very effectively when the particles have short range interaction, but it is applicable to each kind of interaction. The code was tested on a Cray ymp el in

P. Ball, V. M. Braun

We use the QCD sum rule approach to calculate the splitting between vector and pseudoscalar mesons containing one light and one heavy quark, and the kinetic energy of the heavy quark. Our result for the splitting induced by the chromomagnetic interaction agrees to the experimental data on charm and beauty mesons. For the matrix element of the kinetic energy

M. V. Pavlov, R. A. Sharipov, S. I. Svinolupov

Invariant integrability criterion for the equations of hydrodynamical type is found. This criterion is written in the form of vanishing for some tensor which is derived from the velocities matrix of hydrodynamical equations.

P. V. Bayly, E. E. Johnson, P. D. Wolf, H. S. Greenside

As an objective measurement of spatial order in ventricular fibrillation (VF), spatial correlation functions and their characteristic lengths were estimated from epicardial electrograms of pigs in VF. The correlation length of the VF in pigs was found to be approximately 4-10 mm, varying as fibrillation progressed. The degree of correlation decreased in the

G. Bhanot, K. Demeterfi, I. Klebanov

We consider 1+1-dimensional QCD coupled to Majorana fermions in the adjoint representation of the gauge group $SU(N)$. Pair creation of partons (fermion quanta) is not suppressed in the large-$N$ limit, where the glueball-like bound states become free. In this limit the spectrum is given by a linear \lc\ Schr\&#34; odinger equation, which we study numericall

V. Yu. Dobretsov, V. D. Efros, Bin Shao

A new method for studying the many-body response functions is elaborated and first applied to the $^3$He longitudinal response. An integral transform of the response function is calculated from the bound-state-type equations for several versions of the N-N force. The equations are solved with the help of the hyperspherical expansion. The final-state interact

Ya. P. Pugay

We start from the quantum Miura transformation [7] for the $W$-algebra associated with $GL(n)$ group and find an evident formula for quantum L-operator as well as for the action of $W_l$ currents (l=1,..,n) on elements of the completely degenerated n-dimensional representation. Quantum formulae are obtained through the deformation of the pseudodifferential s

P. Blasi, P. Colangelo, G. Nardulli AND N. Paver

Using the QCD sum rules technique we study several aspects of the phenomenology of the b-flavoured strange meson $B_s^0$. In particular, we evaluate the mass of the particle, the leptonic constant and the form factors of the decays $\overline {B_s^0} \to D^{+}_s \ell^- \barν$, $\overline {B_s^0} \to D^{*+}_s \ell^- \barν$, $\overline {B_s^0} \to K^{*+} \ell^

R. Martoňák, E. Tosatti

We have begun a study of quantum ferroelectrics and paraelectrics. Simple 2D short-range lattice model hamiltonians are constructed, keeping in mind the phenomenology of real perovskite systems, like $SrTiO_{3}$ and $KTaO_{3}$. Pertinent quantum tunneling phenomena, and the presence of an ice-like constraint are demonstrated. The two simplest models, namely

R. Martoňák, E. Tosatti

We have considered the processes which lead to elastic scattering between two far ultraviolet or X--ray photons while they propagate inside a solid, modeled as a simple electron gas. The new ingredient, with respect to the standard theory of photon--photon scattering in vacuum, is the presence of low--energy, nonrelativistic electron--hole excitations. Owing

A. Oguri, T. Asahta, S. Maekawa

The Gutzwiller wave function for the three-band Hubbard model on a two dimensional CuO$_2$ plane is studied by using the variational Monte Carlo (VMC) method in the limit $U_d \to \infty$, where $U_d$ is the Coulomb repulsion between holes on a Cu site. The VMC results for the energy and the fraction of $d$-holes are compared with those of the Rice-Ueda type

M. I. Dykman, D. G. Luchinsky, R. Mannella, P. V. E. McClintock

Stochastic resonance (SR) - a counter-intuitive phenomenon in which the signal due to a weak periodic force in a nonlinear system can be {\it enhanced} by the addition of external noise - is reviewed. A theoretical approach based on linear response theory (LRT) is described. It is pointed out that, although the LRT theory of SR is by definition restricted to

J. Kepner, P. Hartigan, C. Yang, S. Strom

We have applied a new restoration technique to archival [O~I], H$α$, and continuum HST images of DG~Tau. The restored [O~I] and H$α$ images show that DG~Tau has a jet with a projected length of 25~AU and width $\leq$10~AU, and is already collimated at a projected distance of $\sim$~40~AU (0\farcs25) from the star. Such a narrow width and short collimation di

J. Fuchs, C. Schweigert

Mappings between certain infinite series of N=2 superconformal coset models are constructed. They make use of level-rank dualities for B, C and D type theories. While the WZW level-rank dualities do not constitute isomorphisms of the theories, they lead to level-rank dualities of N=2 coset models that preserve the cft properties in such a manner that the cos

Meik Hellmund, Jochen Kripfganz, Michael G. Schmidt

We discuss one-loop radiative corrections to the sphaleron-induced baryon number-violating transition rate near the electroweak phase transition in the standard model. We emphasize that in the case of a first-order transition a rearrangement of the loop expansion is required close to the transition temperature. The corresponding expansion parameter, the effe

Claudio O. Dib, J. Taron

A relation among the form factors of $<D \mid A_\mu \mid D^*>$ at $q^2 \to 0$ is derived. It is verified to lowest order in both the $1/m_c$ expansion and the expansion in number of derivatives using the effective lagrangian that incorporates the heavy quark symmetries for the b and c quarks, and the chiral symmetry for the u, d, s quarks.

Alberto Lerda, Stefano Sciuto

We discuss the properties of the supersymmetric $t$-$J$ model in the formalism of the slave operators. In particular we introduce a generalized abelian bosonization for the model in two dimensions, and show that holons and spinons can be anyons of arbitrary complementary statistics (slave anyon representation). The braiding properties of these anyonic operat

J. Isberg, U. Lindström, B. Sundborg, G. Theodoridis

{}From the ordinary tensile string we derive a geometric action for the tensionless ($T=0$) string and discuss its symmetries and field equations. The Weyl symmetry of the usual string is shown to be replaced by a global space-time conformal symmetry in the $T\to 0$ limit. We present the explicit expressions for the generators of this group in the light-cone

F. Delduc, L. Frappat, P. Sorba, F. Toppan

Factoring out the spin $1$ subalgebra of a $ W $ algebra leads to a new $ W $ structure which can be seen either as a rational finitely generated $ W $ algebra or as a polynomial non-linear $ W_\infty$ realization.

M. Martellini, M. Spreafico, K. Yoshida

Two dimensional induced quantum gravity with matter central charge $c>1$ is studied taking a careful consideration of both diffeomorphism and Weyl symmetries . It is shown that, for the gauge fixing condition $R(g)$ (scalar curvature)=$const$, one obtains a modification of the David-Distler-Kawai version of KPZ scaling. We obtain a class of models with the r

P. Lipari

{}From the study of the multiple muon events in deep underground detectors, it is possible to extract information about the spectrum and composition of the primary cosmic rays. In this work the number of TeV muons produced by a primary cosmic ray of a given energy and zenith angle is computed using analytic and montecarlo methods, for a family of simplified

Patrick J. O&#39;Donnell, Humphrey K. K. Tung

We derive general relations among hadronic form factors involving one heavy meson $b\bar{q}$ and another, not necessarily heavy, meson $Q\bar{q}$. The relations are valid to all orders of mass corrections of $m_Q$ .

Alan R. White

If electroweak dynamical symmetry breaking is due to a chiral condensate of color sextet quarks, dynamics analagous to ``walking technicolor&#39;&#39; will enhance the condensate by orders of magnitude compared to the electroweak chiral scale. This enhancement compensates for the exponential suppression of electroweak scale color instanton interactions. As a

Masoud Mohazzab

The order of magnitude of energy emission from cusps to light bosons on ordinary cosmic strings is calculated perturbatively. The analysis is applicable to both closed string loops and long cosmic strings. The perturbative result obtained here is much less than what is found by non-perturbative approximations.

G. Ecker, H. Neufeld, A. Pich

An investigation is performed of all non-leptonic kaon decays sensitive to the chiral anomaly. Within the framework of chiral perturbation theory, there are two classes of anomalous amplitudes at $O(p^4)$: reducible and direct contributions. Only radiative transitions are affected by the anomaly. The phenomenology of the decays $K_L \to π^+ π^- γ$ and $K^+ \

H. Anlauf, H. Dahmen, A. Himmler, P. Manakos

Radiative Corrections to $W$ Pair Production and effects of finite width of the $W$ bosons are studied using the Monte Carlo {\tt WOPPER}. As an example the influence of QED radiative corrections on the reconstruction of the $W$ helicities at LEP 200 and a future 500 GeV $e^+ e^-$ collider is discussed.

J. Segura, J. Bernabéu, F. J. Botella, J. Peñarrocha

We show the existence of dynamical zeros in the helicity amplitudes for neutrino-electron elastic scattering at lowest order in the standard theory. In particular, the $λ=1/2$ non-flip electron helicity amplitude in the electron antineutrino process vanishes for an incident neutrino energy $E_ν=m_{e}/(4sin^{2}θ_{W})$ and forward electrons (maximum recoil ene