October 1995 arXiv papers — page 10

V. D. Dzhunushaliev

The axially symmetric non-local solution in the Heisenberg equation is found. It is regular in the whole space and has the finite energy on the unit of length according to this we may consider the solution as a string. Taking the non-local spherically symmetric solution, which was found by Finkelstein et. al., and our solution in account we suggest to consid

A Calogeracos, N Dombey, K Imagawa

A second quantised theory of electrons and positrons in a deep time-dependent potential well is discussed. It is shown that positron production from the well is a natural consequence of Dirac's hole theory when the strength of the well becomes supercritical. A formalism is developed whereby the amplitude for emission of a positron of a given momentum can

A. Valcarce, F. Fernandez, P. Gonzalez, V. Vento

We study the low energy part of the nucleon and $Δ$ spectra by solving the Schrödinger equation for the three-quark system in the hyperspherical harmonic approach. The quark-quark hamiltonian considered includes, besides the usual one-gluon exchange, pion and sigma exchanges generated by the chiral symmetry breaking. This quark-quark potential reproduces, in

A. Csoto, H. Oberhummer, R. Pichler

We search for three-neutron resonances which were predicted from pion double charge exchange experiments on He-3. All partial waves up to J=5/2 are nonresonant except the J=3/2^+ one, where we find a state at E=14 MeV energy with 13 MeV width. The parameters of the mirror state in the three-proton system are E=15 MeV and Gamma=14 MeV. The possible existence

Walter Van Assche

In a note at the end of his paper {\it Recherches sur les fractions continues}, Stieltjes gave a necessary and sufficient condition when a continued fraction is represented by a meromorphic function. This result is related to the study of compact Jacobi matrices. We indicate how this notion was developped and used since Stieltjes, with special attention to t

André Ronveaux, Walter Van Assche

Orthogonal polynomials on the real line always satisfy a three-term recurrence relation. The recurrence coefficients determine a tridiagonal semi-infinite matrix (Jacobi matrix) which uniquely characterizes the orthogonal polynomials. We investigate new orthogonal polynomials by adding to the Jacobi matrix $r$ new rows and columns, so that the original Jacob

Siqi Fu, Alexander V. Isaev, Steven G. Krantz

In this paper we prove that, if $p$ is a boundary point of a smoothly bounded pseudoconvex Reinhardt domain in $\C^n$, then the variety type at $p$ is identical to the regular type.

Siqi Fu, Alexander V. Isaev, Steven G. Krantz

We give an explicit description of smoothly bounded Reinhardt domains with noncompact automorphism groups. In particular, this description confirms a special case of a conjecture of Greene/Krantz.

B. Dey, Avinash Khare, C. N. Kumar

Many new solitary wave solutions of the recently studied Lienard equation are obtained by mapping it to the field equation of the $ϕ^6-$field theory. Further, it is shown that the exact solutions of the Lienard equation are also the exact solutions of the various perturbed soliton equations. Besides, we also consider a one parameter family of generalised Lie

Andrew E. Chubykalo

Some inadequacy in the traditional description of the phenomenon of electro-magnetic field radiation created by a point charge moving along a straight line with an acceleration is found and discussed in this paper in detail. The possibility of simultaneous coexistence of Newton instantaneous long-range interaction and Faraday-Maxwell short-rang interaction i

G. Chechelashvili, G. Jorjadze, N. Kiknadze

For systems with first class constraints the reduction scheme to the gauge invariant variables is considered. The method is based on the analysis of restricted 1-forms in gauge invariant variables. This scheme is applied to the models of electrodynamics and Yang-Mills theory. For the finite dimensional model with $SU(2)$ gauge group of symmetry the possible

Ronald J. Adler, Ovid C. Jacob

We analyze the initial value problem for scalar fields obeying the Klein-Gordon equation. The standard Cauchy initial value problem for second order differential equation is to construct a solution function in a neighborhood of space and time form values of the function and its time derivative on a selected initial value surface. On the characteristic surfac

Ovid C. Jacob, Ronald J. Adler

We analyze the initial value problem for spinor fields obeying the Dirac equation, with particular attention to the characteristic surfaces. The standard Cauchy initial value problem for first order differential equations is to construct a solution function in a neighborhood of space and time from the values of the function on a selected initial value surfac

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

A new approach with BRST invariance is suggested to cure the degeneracy problem of ill defined path integrals in the path-integral calculationof quantum mechanical tunneling effects in which the problem arises due to the occurrence of zero modes. The Faddeev-Popov procedure is avoided and the integral over the zero mode is transformed in a systematic way int

J. Grundberg, T. H. Hansson, U. Lindström

We use the dual description proposed by Seiberg to calculate the pressure in the low temperature confined phase of $N=1$ supersymmetric QCD using perturbation theory to $O(g^3_m)$, where $g_m$ is the gauge coupling in the dual theory. Combining this result with the usual high temperature expansion based on asymptotic freedom, we study how the physics in the

Josep M. Pons

A complete analysis of the consequences of introducing a set of holonomic gauge fixing constraints (to fix the dynamics) into a singular Lagrangian is performed. It is shown in general that the dynamical system originated from the reduced Lagrangian erases all the information regarding the first class constraints of the original theory, but retains its secon

J. Maeder, W. Ruehl

For the case of the single-O($N$)-vector linear sigma models the critical behaviour following from any $A_k$ singularity in the action is worked out in the double scaling limit $N \rightarrow \infty$, $f_r \rightarrow f_r^c$, $2 \leq r \leq k$. After an exact elimination of Gaussian degrees of freedom, the critical objects such as coupling constants, indices

Phil E. Gibbs

It is sometimes said that there may be a unique algebraic theory independent of space-time topologies which underlies superstring and p-brane theories. In this paper, I construct some algebras using knot relations within the framework of event-symmetric string theory, and ask the question "Is string theory in knots?"

B. Ananthanarayan, D. Toublan, G. Wanders

We derive a set of sum rules for threshold parameters of pion-pion scattering whose dispersion integrals are rapidly convergent and are dominated by S- and P-waves absorptive parts. Stringent constraints on some threshold parameters are obtained.

P. Nason, G. Ridolfi, S. Frixione

We review the status of heavy flavour production in QCD. Comparison of experimental and theoretical results for top and bottom production are given. Selected topics in charm production are also discussed.

L. Bergstrom, P. Gondolo

We analyze the rate of detection of minimal supersymmetric neutralino dark matter in germanium, sapphire and sodium iodide detectors, imposing cosmological and recent accelerator bounds including those from \bsg\ decay. We find, in contrast with several other recent analyses, that although the \bsg\ constraint reduces the number of viable models, models stil

J. Manjavidze

The paper contains the real-time perturbation theory for description of a statistical system with the nonuniform temperature distribution. the formalism based on the Wigner-functions approach. The perturbation theory is formulated in terms of the local-temperature Green functions.

Ivan Horvath

The phase diagram of the Schwinger model on the lattice with one and two degenerate flavours of Wilson fermions is investigated in the Hartree-Fock approximation. In case of a single flavour (not directly amenable to numerical simulation), the calculation indicates the existence of the parity violating phase at both weak and intermediate-to-strong couplings.

M. Göckeler, R. Horsley, E. -M. Ilgenfritz, H. Oelrich

Our objective is to compute the moments of the deep-inelastic structure functions of the nucleon on the lattice. A major source of uncertainty is the renormalization of the lattice operators that enter the calculation. In this talk we compare the renormalization constants of the most relevant twist-two bilinear quark operators which we have computed non-pert

Seyong Kim

Using the Bodwin--Braaten--Lepage factorization theorem in heavy quarkonium decay and production processes, we calculated matrix elements associated with S- and P-wave bottomonium decays via lattice QCD simulation methods. In this work, we report preliminary results on the operator matching between the lattice expression and the continuum expression at one l

Scott C. Smith, Janet L. Houser, Joan M. Centrella

We have carried out 3-D numerical simulations of the dynamical bar instability in a rotating star and the resulting gravitational radiation using both an Eulerian code written in cylindrical coordinates and a smooth particle hydrodynamics (SPH) code. The star is modeled initially as a polytrope with index $n = 3/2$ and $T_{\rm rot}/|W| \approx 0.30$, where $

David Hartley

The principal properties of geodesic normal coordinates are the vanishing of the connection components and first derivatives of the metric components at some point. It is well-known that these hold only at points where the connection has vanishing torsion and non-metricity. However, it is shown that normal frames, possessing the essential features of normal

Mariano Cadoni

Black hole solutions in the context of a generic matter-coupled two-dimensional dilaton gravity theory are discussed both at the classical and semiclassical level. Starting from general assumptions, a criterion for the existence of black holes is given. The relationship between conformal anomaly and Hawking radiation is extended to a broad class of two-dimen

Doug Pickrell

The purpose of this paper is to describe some conjectures and results on the existence and uniqueness of invariant measures on formal completions of Kac-Moody groups and associated homogeneous spaces. Existence is rigorously established in all affine type cases.

C. Q. Wu, Q. F. Huang, X. Sun

Effects of quantum phonon fluctuations on the Peierls dimerization in the one-dimensional molecular crystal model are reexamined by a functional integral approach. An equation for the dimerization order parameter is obtained within a one-loop approximation. The destruction of Peierls dimerization is found by taking the quantum phonon fluctuations into accoun

D. F. B. ten Haaf, J. M. J. van Leeuwen

In a previous paper, we have described a method to perform Fixed-Node Quantum Monte Carlo calculations for lattice fermions. In this paper, we present an extension of this method, by which it is possible to find information on the properties of the exact ground-state wave function. We give some further illustrations of the FNMC and the extended methods.

Achilles D. Speliotopoulos, Harry L. Morrison

The superfluid phase transition of the general vortex gas, in which the circulations may be any non-zero integer, is studied. When the net circulation of the system is not zero the absence of a superfluid phase is shown. When the net circulation of the vortices vanishes, the presence of off-diagonal long range order is demonstrated and the existence of an or

Jakyoung Song, Sergio E. Ulloa

Excitons confined to flat semiconductor quantum dots with elliptical cross section are considered as we study geometrical effects on exciton binding energy, electron-hole separation, and the resulting linear optical properties. We use numerical matrix diagonalization techniques with appropriately large and optimized basis sets in an effective-mass Hamiltonia

Ted Briscoe, John Carroll

We describe an approach to robust domain-independent syntactic parsing of unrestricted naturally-occurring (English) input. The technique involves parsing sequences of part-of-speech and punctuation labels using a unification-based grammar coupled with a probabilistic LR parser. We describe the coverage of several corpora using this grammar and report the re

Aniruddha R. Thakar, Barbara S. Ryden

We present results of numerical simulations of the formation of a massive counterrotating gas disk in a spiral galaxy. Using a hierarchical tree gravity solver combined with a sticky-particle gas dissipation scheme for our simulations, we have investigated three mechanisms: episodic and continuous gas infall, and a merger with a gas-rich dwarf galaxy. We fin

Ian R. Walker, J. Christopher Mihos, Lars Hernquist

We perform fully self-consistent stellar dynamical simulations of the accretion of a companion ("satellite") galaxy by a large disk galaxy to investigate the interaction between the disk, halo, and satellite components of the system during a merger. Our fiducial encounter begins with a satellite in a prograde, circular orbit inclined thirty degrees w

Ana Campos

In these Lectures Notes I re-visit the problem of the deep number counts as a viable method to (1) study the evolution of the galaxy population in the past and (2) determine the value of the deceleration parameter $q_0$. After a brief description of the basic concepts needed to model the counts, we show that simple luminosity evolution models which incorpora

Myriam Mondragon, Lukas Nellen, Michael G. Schmidt, Christian Schubert

We construct a world-line representation for the fermionic one-loop effective action with axial and also vector, scalar, and pseudo-scalar couplings. We use this expression to compute a few selected scattering amplitudes. These allow us to verify that our method yields the same results as standard field theory. In particular, we are able to reproduce the chi

Y. B. He, C. S. Gao, X. Q. Li, W. Q. Chao

A comprehensive study of the properties of strangelets at zero and finite temperature is presented within the framework of liquid drop model, including the essential finite size effects. Strong parameter dependences of the properties are found and discussed.

X. W. Pan, J. L. Ping, D. H. Feng, C. L. Wu

The even--even and even--odd nuclei $^{126}$Xe-$^{132}$Xe and $^{131}$Ba-$^{137}$Ba are shown to have a well-realized $SO_8 \supset SO_6 \supset SO_3$ fermion dynamical symmetry. Their low-lying energy levels can be described by a unified analytical expression with two (three) adjustable parameters for even--odd (even--even) nuclei that is derived from the f

M. W. Guidry, D. H. Feng, X. W. Pan, C. -L. Wu

The dynamical symmetries of the Fermion Dynamical Symmetry Model are used as a principle of truncation for the spherical shell model. Utilizing the usual principle of energy-dictated truncation to select a valence space, and symmetry-dictated truncation to select a collective subspace of that valence space, we are able to reduce the full shell model space to

Feruenc Pinteŕ, Paul G. Nevai

We apply a theorem of Geronimus to derive some new formulas connecting Schur functions with orthogonal polynomials on the unit circle. The applications include the description of the associated measures and a short proof of Boyd's result about Schur functions. We also give a simple proof for the above mentioned theorem of Geronimus.

Leonid B. Golinskii, Paul G. Nevai, Walter Van Assche

Orthogonal polynomials on the unit circle are completely determined by their reflection coefficients through the Szegő recurrences. We assume that the reflection coefficients converge to some complex number a with 0 < |a| < 1. The polynomials then live essentially on the arc {e^(i theta): alpha <= theta <= 2 pi - alpha} where cos alpha/2 = sqrt(1-|a|^2) with

The ZEUS Collaboration

Jet production in deep inelastic scattering for $120<Q^2<3600$~GeV$^2$ has been studied using data from an integrated luminosity of 3.2~pb$^{-1}$ collected with the ZEUS detector at HERA. Jets are identified with the JADE algorithm. A cut on the angular distribution of parton emission in the $γ^*$-parton centre-of-mass system minimises the experimental and t

Yasuko Munehisa

We present quantum Monte Carlo results for the Hubbard model on a ladder using the re-structuring method which employ eigenstates of two-site system on a rung to construct a complete set. From technical reasons we concentrate on the case in which the hopping along the leg is much less than the hopping on the rung. We observe the ground state of the half-fill

Ian Smail, Mark Dickinson

We present the detection of weak gravitational lensing in the field of the radio galaxy 3C324 (z=1.206) using deep HST imaging. ~From an analysis of the shapes of faint R=24.5-27.5 galaxies in the field we measure a weak, coherent distortion centered close to the radio source. This shear field most likely arises from gravitational lensing of distant field ga

K. B. Fisher, A. Nusser

We examine the anisotropies in the power spectrum by the mapping of real to redshift space. Using the Zel&#39;dovich approximation, we obtain an analytic expression for the nonlinear redshift space power spectrum in the distant observer limit. For a given unbiased galaxy distribution in redshift space, the anisotropies in the power spectrum depend on the par

J. -P. Kneib, G. Soucail

The gravitational lensing of faint background galaxies by rich clusters is emerging as a very efficient method to constrain both the mass distribution of cluster of galaxies and probe the statistical properties of faint background galaxies. We review here the results concerning the core of cluster lenses, where recent Hubble Space Telescope (HST) images are

I. Aretxaga, B. J. Boyle, R. J. Terlevich

We have been conducting an imaging survey to detect host galaxies of radio-quiet QSOs at high redshift (z = 2), in order to compare them with those of radio-loud objects. Six QSOs were observed in the R passband with the auxiliary port of the 4.2m WHT of the {\it Observatorio de Roque de los Muchachos} indir August 1994. The objects were selected to be brigh

D. Saumon, W. B. Hubbard, A. Burrows, T. Guillot

We present a broad suite of models of extrasolar giant planets (EGP&#39;s), ranging in mass from 0.3 to 15 Jupiter masses. The models predict luminosity (both reflected and emitted) as a function of age, mass, deuterium abundance and distance from parent stars of various spectral type. We also explore the effects of helium mass fraction, rotation rate and th

Lennox L. Cowie, Esther M. Hu, Antoinette Songaila

The complex problem of when and how galaxies formed has not until recently been susceptible of direct attack. It has been known for some time that the excessive number of blue galaxies counted at faint magnitudes implies that a considerable fraction of the massive star formation in the universe occurred at z < 3, but, surprisingly, spectroscopic studies of g

Valeri A. Gritsenko, Viacheslav V. Nikulin

We consider the variant of Mirror Symmetry Conjecture for K3 surfaces which relates &#34;geometry&#34; of curves of a general member of a family of K3 with &#34;algebraic functions&#34; on the moduli of the mirror family. Lorentzian Kac--Moody algebras are involved in this construction. We give several examples when this conjecture is valid.

N. Hambli, R. T. Sharp

Basis states and generator matrix elements are given for the generic representation $(a,b)$ of $G_2$ in an $SU(3)$ basis.

A. A. Tseytlin

We consider a 2-parameter class of solvable closed superstring models which `interpolate&#39; between Kaluza-Klein and dilatonic Melvin magnetic flux tube backgrounds. The spectrum of string states has similarities with Landau spectrum for a charged particle in a uniform magnetic field. The presence of spin-dependent `gyromagnetic&#39; interaction implies br

Yoshitaka Okumura, Katsusada Morita

The scheme previously proposed by the present authors is modified to incorporate the strong interaction by affording the direct product internal symmetry. We do not need to prepare the extra discrete space for the color gauge group responsible for the strong interaction to reconstruct the standard model and the left-right symmetric gauge model(LRSM). The app

Y. Okumura, S. Suzuki, K. Morita

Sogami recently proposed the new idea to express Higgs particle as a kind of gauge particle by prescribing the generalized covariant derivative with gauge and Higgs fields operating on quark and lepton fields. The field strengths for both the gauge and Higgs fields are defined by the commutators of the covariant derivative by which he could obtain the Yang-M

John R. Klauder

A fully geometric procedure of quantization that utilizes a natural and necessary metric on phase space is reviewed and briefly related to the goals of the program of geometric quantization.

Hikoya Kasari, Yoshio Yamaguchi

We investigate parity violation in neutron-nucleus collisions at very low energy region $(E \leq 100 \ev)$, including resonance states. We use the coupled channel formalism for resonances with radiative emission. The parity mixing between resonances with opposite parities is taken into account. Finally, our theory is applied to $n-^{139}$La collision and rel

Jorge Soto-Andrade, Jorge Vargas

We prove that the induced representation from a non trivial character of the Coxeter torus of GL$(2,F)$, for a finite field $F$, is multiplicity-free; we give an explicit description of the corresponding (twisted) spherical functions and a version of the Heisenberg Uncertainty Principle.

Pietro Menotti, Pier Paolo Peirano

By regularizing the conical singularities by means of a segment of a sphere or pseudosphere and then taking the regulator to zero, we compute exactly the Faddeev--Popov determinant related to the conformal gauge fixing for a piece-wise flat surface with the topology of the sphere. The result is analytic in the opening angles of the conical singularities in t

Mario Belloni, Lusheng Chen, Kurt Haller

We construct a transformation that transforms perturbative states into states that implement Gauss&#39;s law for `pure gluonic&#39; Yang-Mills theory and QCD. The fact that this transformation is not and cannot be unitary has special significance. Previous work has shown that only states that are unitarily equivalent to perturbative states necessarily give t

Alexis E. Koshelev, Pierre Le Doussal, Valerii M. Vinokur

We investigate fluctuations of Josephson-coupled pancake vortices in layered superconductors in the presence of columnar defects. We study the thermodynamics of a single pancake stack pinned by columnar defects and obtain the temperature dependence of localization length, pinning energy and critical current. We study the creep regime and compute the crossove

Konstadinos Sfetsos

World-sheet and spacetime supersymmetries that are manifest in some string backgrounds may not be so in their T-duals. Nevertheless, they always remain symmetries of the underlying conformal field theory. In previous work the mechanism by which T-duality destroys manifest supersymmetry and gives rise to non-local realizations was found. We give the general c

B. Holdom

Four-fermion operators with large anomalous dimension may feed down mass to quarks and leptons from a heavy fourth family. No technicolor sector is required. A model illustrates the origin of the large top mass along with quark mass hierarchies and mass mixings.

F. Delduc, E. Ivanov, S. Krivonos

We present the results of further analysis of the integrability properties of the $N=4$ supersymmetric KdV equation deduced earlier by two of us (F.D. \& E.I.) as a hamiltonian flow on $N=4$ $SU(2)$ superconformal algebra in the harmonic $N=4$ superspace. To make this equation and the relevant hamiltonian structures more tractable, we reformulate it in the o

H. Arthur Weldon

In momentum space the Feynman propagator $D_{F}(k)$ at non-zero temperature is defined by a simple dispersion relation with the familiar property of being an even function of $k^{0}$ and analytic for Re$(k^{0})^{2}>0$. The coordinate space form of the propagator $D_{F}(x)$ is expressed directly in terms of matrix elements of the field operator and requires a

K. Zarembo

The fluctuation determinant in the BPS monopole background is calculated in the finite--temperature SU(2) gauge theory.

L. V. Verozub

It is shown that gravitational theory allows stable equilibrium configurations of the degenerated Fermi gas, whose masses are many times as large as the Sun. They have no events horizon at the Schwarzchild radius from the center. They are objects with low luminosity and they are new candidates to Dark Matter in the Universe. Orbits of test particles near the

Sergio Caracciolo, Andrea Pelissetto

We compute the four-loop contributions to the $β$-function and the anomalous dimension of the field for the $O(N)$-invariant $N$-vector model. These results are used to compute the second analytic corrections to the correlation length and the general spin-$n$ susceptibility.

Ted Pyne, Sean M. Carroll

We study the behavior of light rays in perturbed Robertson-Walker cosmologies, calculating the redshift between an observer and the surface of last scattering to second order in the metric perturbation. At first order we recover the classic results of Sachs and Wolfe, and at second order we delineate the various new effects which appear; there is no {\it a p

Didier Sornette, Christian Vanneste

We study a 2D quasi-static discrete {\it crack} anti-plane model of a tectonic plate with long range elastic forces and quenched disorder. The plate is driven at its border and the load is transfered to all elements through elastic forces. This model can be considered as belonging to the class of self-organized models which may exhibit spontaneous criticalit

Everton M. C. Abreu, Nelson R. F. Braga

It is shown that the quantum master equation of the Field Antifield quantization method at one loop order can be translated into the requirement of a superfield structure for the action. The Pauli Villars regularization is implemented in this BRST superspace and the case of anomalous gauge theories is investigated. The quantum action, including Wess Zumino t

Harry G. Blundell, Stephen Godfrey, Brian Phelps

We studied properties of the strange axial mesons in the relativized quark model. We calculated the $K_1$ decay constant in the quark model and showed how it can be used to extract the $K_1 (^3P_1) - K_1 (^1P_1)$ mixing angle ($\theta_K$) from the weak decay $\tau \to K_1 \nu_\tau$. The ratio $BR(\tau \to \nu_\tau K_1 (1270))/BR(\tau\to \nu_\tau K_1(1400))$

Chung-Yi Wu

We calculate with chiral symmetry the parton contents of the proton based on a two-component wave function. The calculation results give significant sea-quark contents and, especially, the intrinsic gluon polarization produced at a more fundamental level.

Guang-Ming Zhang, Zhao-Bin Su, Lu Yu

A generalized Anderson single-impurity model with off-site Coulomb interactions is derived from the extended three-band Hubbard model, originally proposed to describe the physics of the copper-oxides. Using the abelian bosonization technique and canonical transformations, an effective Hamiltonian is derived in the strong coupling limit, which is essentially

R. Plaga

The many-worlds interpretation of quantum mechanics predicts the formation of distinct parallel worlds as a result of a quantum mechanical measurement. Communication among these parallel worlds would experimentally rule out alternatives to this interpretation. A procedure for ``interworld&#39;&#39; exchange of information and energy, using only state of the

L. Lemaire, J. C. Wood

Carrying further work of T.A. Crawford, we show that each component of the space of harmonic maps from the $2$-sphere to complex projective $2$-space of degree $d$ and energy $4 πE$ is a smooth closed submanifold of the space of all $C^j$ maps $(j \geq 2)$. We achieve this by showing that the Gauss transform which relates them to spaces of holomorphic maps o

Piotr M. Hajac

Two toy models are considered within the framework of noncommutative differential geometry. In the first one, the Einstein action of the Levi-Civita connection is computed for the algebra of matrix valued functions on a torus. It is shown that, assuming some constraints on the metric, this action splits into a classical-like, a quantum-like and a mixed term.

Yuri Bespalov, Bernhard Drabant

Hopf (bi-)modules and crossed modules over a bialgebra B in a braided monoidal category C are considered. The (braided) monoidal equivalence of both categories is proved provided B is a Hopf algebra (with invertible antipode). Bialgebra projections and Hopf bimodule bialgebras over a Hopf algebra in C are found to be isomorphic categories. As a consequence a

Louis Funar

We get a detailed account of Vassiliev type invariants starting with Chen&#39;s theory of iterated integrals and Malcev&#39;s completion of discrete groups. The canonical injection of the group of pure braids into its completion is identified with the universal Kontsevich-Vassiliev invariant.Further we discuss the extension of this morphism to the whole brai

P. Bonche, H. Flocard, P. -H. Heenen

The cranked Hartree-Fock-Bogoliubov method presented in previous studies of superdeformed bands in Hg and Pb isotopes is applied to the study of superdeformed bands in Gd150, Dy152, Dy151 and Tb151. The same density-dependent zero-range pairing interaction used in the A=190 mass region leads to a similarly good agreement with the experimental data. In partic

V. R. Manfredi, M. Rosa-Clot, L. Salasnich, S. Taddei

We show that the collective vibrational model of atomic nuclei displays quantum chaos. To avoid the problems related to the tunneling effects, a Green function deterministic numerical method has been used to evaluate the energy levels.

Stephen W. Hawking

One would expect spacetime to have a foam-like structure on the Planck scale with a very high topology. If spacetime is simply connected (which is assumed in this paper), the non-trivial homology occurs in dimension two, and spacetime can be regarded as being essentially the topological sum of $S^2\times S^2$ and $K3$ bubbles. Comparison with the instantons

E. Alvarez, L. Alvarez-Gaume, I. Bakas

Duality transformations with respect to rotational isometries relate supersymmetric with non-supersymmetric backgrounds in string theory. We find that non-local world-sheet effects have to be taken into account in order to restore supersymmetry at the string level. The underlying superconformal algebra remains the same, but in this case T-duality relates loc

G. Veneziano

After recalling a few basic concepts from cosmology and string theory, I will outline the main ideas/assumptions underlying (our own group&#39;s approach to) string cosmology and show how these lead to the definition of a two-parameter family of ``minimal&#34; models. I will then briefly explain how to compute, in terms of those parameters, the spectrum of s

Theodore A. Jacobson

The aim of these notes is both to review the standard understanding of the Hawking effect, and to discuss the modifications to this understanding that might be required by new physics at short distances. The fundamentals of the Unruh effect are reviewed, and then the Hawking effect is explained as a ``gravitational Unruh effect&#34;, with particular attentio

Marcello Ciafaloni

I review the k-factorization method to combine the high-energy behaviour in QCD with the renormalization group. Resummation formulas for coefficient functions and anomalous dimensions are derived, and their applications to small-x scaling violations in structure functions are briefly discussed.

J. S. Shim, H. S. Song

The study of factorization in linearized gravity is extended to the graviton scattering processes with an electron for the massive vector boson productions such as $g e \rightarrow Z e$ and $g e \rightarrow W ν_e$. It is shown that every transition amplitude is completely factorized due to gravitational gauge invariance and Lorentz invariance. Also the expli

Victor T. Kim, Grigorii B. Pivovarov

We calculate inclusive dijet production cross section in high energy hadron collisions within the BFKL resummation formalism for the QCD Pomeron. We take into account the Pomerons which are adjacent to the hadrons. With these adjacent Pomerons we define a new object - the BFKL structure function of hadron - which enables one to calculate the inclusive dijet

J. Ellis, J. Lopez, D. Nanopoulos

We show that the prediction for $α_s(M_Z)$ in flipped SU(5) is naturally lower than in minimal SU(5), and that the former can accommodate the full range of $α_s(M_Z)$ presently allowed by experiment. Our computations include two-loop ($δ_{\rm 2loop}$) and light ($δ_{\rm light}$) and heavy ($δ_{\rm heavy}$) threshold effects. Unlike minimal SU(5), in flipped

Sergio Lupia

Single particle inclusive energy spectra in $e^+e^-$ annihilation are analyzed in terms of moments. By assuming Local Parton Hadron Duality (LPHD), experimental data in a wide c.m. energy range from 3 GeV up to LEP energy are compared to the theoretical predictions of Modified Leading Log Approximation (MLLA) of QCD with and without taking into account the r

T. Gehrmann, W. J. Stirling

A review of the present knowledge on polarized parton distributions is given. The effects of perturbative evolution on these distributions are discussed qualitatively and a comparison of various recent parametrizations is made.

J. S. Shim, S. W. Baek, H. S. Song

The electroweak production processes of vector bosons, $e^+ e^- \rightarrow Z γ$, $γe \rightarrow Ze$, and $γe \rightarrow W ν$ are considered simultaneousely and in the Standard model the covariant polarization density matrices of vector bosons for these processes are obtained explicitly from one of the processes, $γe \rightarrow Z e$. The effect of the pho

Tsung-Wen Yeh, Chien-er Lee

We derive the mass correction lagrangian of the heavy meson effective theory by using the projection operator method. The next leading order of the mass correction and the first order of the chiral expansion are given explicitely.We also consider the mass correction weak lagrangian of the heavy mesons. Finally, we give the $\it{D}^{*+}\to \it{D}^o π^{+}$ dec

Tsung-Wen Yeh, Chien-er Lee

The mass correction forms of the arbitrary spin heavy hadrons are derived by using the projection operator method. The Bjorken sum rule for finite mass is derived by using the results of here.

A. V. Berezhnoy, V. V. Kiselev, A. K. Likhoded

Numerical calculations for the production of $P$-wave levels of $B_c$ quarkonium in $γγ$ collisions are performed in the leading $O(α_s^2α_{em}^2)$ order of perturbation theory. The total cross-section of $P$-wave state production is about 10 \% of that for the $S$-wave levels. The contribution of fragmentation component ($6+6$ diagrams) is low, and the basi

Xiaoyuan Li, Yi Liao

Renormalization of the axial vector currents due to Goldstone loops is studied in a simple extension of Manohar - Georgi chiral quark model which incorporates $U(1)_A$ anomaly effects. The polarized strage quark sea in the polarized nucleon results from different renormalization of the flavor singlet and octet currents and is in reasonable agreement with the

S. Aoki, A. Ukawa, T. Umemura

Finite-temperature phase structure of lattice QCD with the Wilson quark action is analyzed. We show that the critical line at finite temperatures, defined to be the line of vanishing pion screening mass, turns back toward strong coupling, forming a cusp on the $(β, K)$ plane, and that the line of thermal transition runs past the tip of the cusp without touch

JLQCD Collaboration

Statistical properties of effective mass are analyzed. We show from a general ground that effective mass as a function of time should not exhibit long plateaux whatever high statistics simulations are made: the mass should fluctuate beyond the one standard deviation of error bars after a few time slices for large times where the ground state dominates. This

JLQCD Collaboration

We present a status report of our ongoing effort toward a precision determination of the kaon $B$ parameter with the Kogut-Susskind quark action in quenched QCD. Results for $B_K$ so far accumulated at $β=5.85$, 5.93, 6.0 and 6.2 corresponding to $a^{-1}=1.3-2.6$ GeV do not exhibit the theoretically expected $O(a^2)$ behavior, but are apparently more consist