arXiv papers from May 1999

Noam D. Elkies

In an investigation of the applications of Combinatorial Game Theory to chess, we construct novel mutual Zugzwang positions, explain an otherwise mysterious pawn endgame from "A Guide to Chess Endings" (Euwe and Hooper), show positions containing non-integer values (fractions, switches, tinies, and loopy games), and pose open problems concerning the values t

Edi Halyo

We consider gauge coupling unification in models with TeV scale strings and large compact dimensions realized as type IIB string orientifolds. Following an observation by Ibanez we show that the gauge couplings at low energies can behave as if they effectively unify at $M_U \sim 2 \times 10^{16} GeV$ with $\alpha_U \sim 1/24$. This requires the $\sigma$ mode

D. Blaschke, P. C. Tandy

A simple confining separable interaction Ansatz for the rainbow-ladder truncated QCD Dyson-Schwinger equations is used to implement chiral restoration and quark deconfinement in a study of $\bar q q$ meson states at finite temperature. The model is fixed at T=0 by reproducing selected pi and rho properties. Deconfinement and chiral restoration are found to b

Martin Rainer

General definitions for causal structures on manifolds of dimension d+1>2 are presented for the topological category and for any differentiable one. Locally, these are given as cone structures via local (pointwise) homeomorphic or diffeomorphic abstraction from the standard null cone variety in R^{d+1}. Weak and strong local cone (LC) structures refer to the

Ali Kaya

According to the positive energy conjecture of Horowitz and Myers, there is a specific supergravity solution, AdS soliton, which has minimum energy among all asymptotically locally AdS solutions with the same boundary conditions. Related to the issue of semiclassical stability of AdS soliton in the context of pure gravity with a negative cosmological constan

Tomomi Muto

We study brane configurations corresponding to D-branes on complex three-dimensional orbifolds ${\bf C}^3/\Gamma$ with $\Gamma=\Delta(3n^2)$ and $\Delta(6n^2)$, nonabelian finite subgroups of SU(3). We first construct a brane configuration for ${\bf C}^3/{\bf Z}_n \times {\bf Z}_n$ by using D3-branes and a web of (p,q) 5-branes of type IIB string theory. Bra

Sreerup Raychaudhuri

Supersymmetric models without conservation of R-parity are reviewed and low-energy constraints on the extra trilinear couplings listed. Current searches at the LEP, Tevatron and HERA colliders are then summed up. Prospects for further study, especially at future colliders, are briefly touched upon.

Wellington da Cruz

Fractons are anyons classified into equivalence classes and they obey a specific fractal statistics. The equivalence classes are labeled by a fractal parameter or Hausdorff dimension $h$. We consider this approach in the context of the Fractional Quantum Hall Effect (FQHE) and the concept of duality between such classes, defined by $\tilde{h}=3-h$ shows us t

A. B. Shick, Yu. N. Gornostyrev, A. J. Freeman

The symmetry-induced magnetic anisotropy due to monoatomic steps at strained Ni films is determined using results of first - principles relativistic full-potential linearized augmented plane wave (FLAPW) calculations and an analogy with the N\'eel model. We show that there is a magnetoelastic anisotropy contribution to the uniaxial magnetic anisotropy energy

C. P. Viazminsky

Incompressible fields are of a special importance in electrodynamics, fluid mechanics, and quantum mechanics. We shall derive a few expressions for such fields in a Riemannian manifold, and show how to generate an incompressible field from an arbitrary set of scalar differentiable functions. The concept of compressibility removing factors of an arbitrary vec

J. De Luca, A. Lichtenberg, S. Ruffo

We study the time scale T to equipartition in a 1D lattice of N masses coupled by quartic nonlinear (hard) springs (the Fermi-Pasta-Ulam beta model). We take the initial energy to be either in a single mode gamma or in a package of low frequency modes centered at gamma and of width delta-gamma, with both gamma and delta-gamma proportional to N. These initial

Pieter G. van Dokkum, Marijn Franx, Daniel Fabricant, Daniel D. Kelson

We present a morphological study of the galaxy population of the luminous X-ray cluster MS1054-03 at z=0.83. The sample consists of 81 spectroscopically confirmed cluster members in a 3 x 2 Mpc area imaged in F606W and F814W with WFPC2. We find thirteen ongoing mergers in MS1054-03, comprising 17% of the L > L* cluster population. Most of these mergers will

Carlo Ewerz

I explain the motivation for investigating the high energy limit of QCD and give a brief presentation of recent progress in the understanding of unitarity corrections in this kinematic regime. Special emphasis is given to the conformal field theory structure discovered in these unitarity corrections.

Lian-Ao Wu, Mike Guidry, Yang Sun, Cheng-Li Wu

We use generalized coherent states to analyze the SO(5) theory of high-temperature superconductivity and antiferromagnetism. We demonstrate that the SO(5) symmetry can be embedded in a larger algebra that allows it to be interpreted as a critical dynamical symmetry interpolating between antiferromagnetic and superconducting phases. This dynamical interpretat

W. -J. Huang, S. -C. Gou

A hydrodynamic description is used to study the zero-temperature properties of a trapped spinor Bose-Einstein condensate in the presence of a uniform magnetic field. We show that, in the case of antiferromagnetic spin-spin interaction, the polar and ferromagnetic configurations of the ground state can coexist in the trap. These two phases are spatially segre

J. Gegenberg, G. Kunstatter

We examine the dynamics induced on the four dimensional boundary of a five dimensional anti-deSitter spacetime by the five dimensional Chern-Simons theory with gauge group the direct product of SO(4,2) with U(1). We show that, given boundary conditions compatible with the geometry of 5d AdS spacetime in the asymptotic region, the induced surface theory is th

J Williams

The requirement of a large pseudo-rapidity gap to select diffractive DIS events at HERA restricts the kinematically accessible region of phase space for a significant range of $Q^2$, $\beta$ and $\xpom$. Consequences of this include a breakdown of $\xpom$-factorization in large rapidity gap diffractive samples and an enhancement in the relative contribution

Marcy Barge, James Jacklitch, Gioia Vago

Suppose that f and g are Markov surjections, each defined on a wedge of circles, each fixing the branch point and having the branch point as the only critical value. We show that if the points in the inverse limit spaces associated with f and g corresponding to the branch point are distinguished then these inverse limit spaces are homeomorphic if and only if

R. Shyam, K. Bennaceur, J. Okolowicz, M. Ploszajczak

We investigate the Coulomb dissociation of 8B on 208Pb target at the beam energy of 250 MeV/nucleon, employing the cross sections for the radiative capture reaction 7Be(p,gamma)8B calculated within the Shell Model Embedded in the Continuum (SMEC) approach. In contrast to the situation at lower beam energies, the Coulomb breakup cross sections are found to be

O. Scavenius, A. Dumitru

We propose a novel mechanism for DCC formation in a first-order chiral phase transition. In this case the effective potential for the chiral order parameter has a local minimum at $\Phi\sim 0$ in which the chiral field can be ``trapped''. If the expansion is sufficiently fast a bubble of disoriented chiral field can emerge and decouple from the rest of the f

S. Capitani, M. Gockeler, R. Horsley, H. Perlt

Within the framework of lattice QCD a high statistics computation of the nucleon axial and tensor charges is given. Particular attention is paid to the chiral and continuum extrapolations.

Denis Uglov

The aim of this paper is to generalize several aspects of the recent work of Leclerc-Thibon and Varagnolo-Vasserot on the canonical bases of the level 1 q-deformed Fock spaces due to Hayashi. Namely, we define canonical bases for the higher-level q-deformed Fock spaces of Jimbo-Misra-Miwa-Okado and establish a relation between these bases and (parabolic) Kaz

D. A. Demir

The explicit CP violation in the MSSM radiatively induces a finite unremovable alignment between the Higgs doublets. This additinal phase can be as large as the original CP phases in certain portions of the MSSM parameter space. Considering the specific case of the charginos, this additional phase is shown to induce a conceivable amount of CP violation near

Robi Peschanski

We discuss the phenomenological and theoretical implications of recent progresses in the evaluation of multi-Pomeron vertices in high-energy perturbative QCD.

D. Metaxas, V. P. Nair

Yang-Mills theory at finite temperature is rewritten as a theory of plasmons which provides a Hamiltonian framework for perturbation theory with resummation of hard thermal loops.

Anna Ceresole, Gianguido Dall'Agata, Riccardo D'Auria, Sergio Ferrara

We derive the full Kaluza-Klein spectrum of type IIB supergravity compactified on AdS_5 x T^{11} with T^{11} = (SU(2) x SU(2))/U(1). From the knowledge of the spectrum and general multiplet shortening conditions, we make a refined test of the AdS/CFT correspondence, by comparison between various shortenings of SU(2,2|1) supermultiplets on AdS_5 and different

Ulf H. Danielsson, Esko Keski-Vakkuri, Martin Kruczenski

We investigate the collapse of a spherical shell of matter in an anti-de Sitter space. We search for a holographic description of the collapsing shell in the boundary theory. It turns out that in the boundary theory it is possible to find information about the radial size of the shell. The shell deforms the background spacetime, and the deformed background m

Claudia Glasman

Measurements of inclusive jet and dijet cross sections in photoproduction and deep inelastic scattering are presented. These measurements provide new tests of QCD, constrain the parton densities of the proton and the photon, and allow the search for new physics. Measurements of jet shapes are reported and used to test the differences between quark and gluon

R. Casalbuoni, S. De Curtis, D. Dominici, R. Gatto

We assume the latest experimental determination of the weak charge of atomic cesium and analyze its implications for possible new physics. We notice that the data would imply positive upper and lower bounds on the new physics contribution to the weak charge, $\delta_NQ_W$. The required new physics should be of a type not severely constrained by the high ener

J. Kwiecinski, L. Motyka

We calculate the total cross-section for $\gamma^* \gamma^*$ collisions and for the process $e^+ e^- \to e^+ e^- + hadrons$ with two tagged leptons assuming dominance of the QCD pomeron exchange. We solve the BFKL equation including the dominant subleading effects generated by the consistency constraint which restricts the available phase-space of the emitte

M. Ciafaloni, D. Colferai, G. P. Salam

We propose and analyze an improved small-x equation which incorporates exact leading and next-to-leading BFKL kernels on one hand and renormalization group constraints in the relevant collinear limits on the other. We work out in detail the recently proposed omega-expansion of the solution, derive the Green's function factorization properties and discuss bot

L. Bertini, E. N. M. Cirillo, E. Olivieri

In this paper we study a renormalization-group map: the block averaging transformation applied to Gibbs measures relative to a class of finite range lattice gases, when suitable strong mixing conditions are satisfied. Using block decimation procedure, cluster expansion (like in [HK]) and detailed comparison between statistical ensembles, we are able to prove

Thorsten Wengler

The production of high transverse momentum piz^0-mesons has been measured in deep-inelastic e-p scattering events at low Bjorken-$x$ taken with the H1 detector at HERA. The production of high p_T particles is strongly correlated to the emission of hard partons in QCD and is therefore sensitive to the dynamics of the strong interaction. For the first time the

Aleksander Filip Zarnecki

In a search for signatures of physics processes beyond the Standard Model, various eeqq vector contact interaction hypotheses have been tested in the ZEUS experiment. No significant evidence of a contact interaction signal has been found. The analysis is based on NC e+p DIS data corresponding to an integrated luminosity of 47.7 pb-1 and results in 95% CL lim

U. Guenther, A. Zhuk

For any multidimensional theory with compactified internal spaces, conformal excitations of the internal space metric result in gravitational excitons in the external spacetime. These excitations contribute either to dark matter or to cross sections of usual particles.

S. M. Troshin, N. E. Tyurin

We consider low-$x$ behavior of the spin structure functions $g_1(x)$ and $h_1(x)$ in the unitarized chiral quark model that combines the ideas on constituent quark structure of hadrons with a geometrical scattering picture and unitarity. A nondiffractive singular low-$x$ dependence of $g^p_1(x)$ and $g_1^n(x)$ is obtained and a diffractive type smooth behav

P. J. Mulders

We discuss specific observables that can be measured in deep inelastic leptoproduction in the case of 1-particle inclusive measurements, namely azimuthal asymmetries. These asymmetries contain information on the intrinsic transverse momentum of partons, with close connection to the gluon dynamics in hadrons.

Leszek Zawiejski

The fragmentation properties in deep-inelastic scattering (DIS) at HERA are investigated in order to test perturbative QCD and quark fragmentation universality. Selected results for the inclusive single particle distributions and the angular two-particle correlations in the current region of the Breit frame are presented and compared to results from $e^{+}e^

S. Seshadri, S. Lakshmibala, V. Balakrishnan

A simple technique is used to obtain a general formula for the Berry phase (and the corresponding Hannay angle) for an arbitrary Hamiltonian with an equally-spaced spectrum and appropriate ladder operators connecting the eigenstates. The formalism is first applied to a general deformation of the oscillator involving both squeezing and displacement. Earlier r

S. Seshadri, V. Balakrishnan, S. Lakshmibala

We present some analytic, non-perturbative results for the invariant density rho(x) for noisy one-dimensional maps at fully developed chaos. Under periodic boundary conditions, the Fourier expansion method is used to show precisely how noise makes rho(x) absolutely continuous and smoothens it out. Simple solvable models are used to illustrate the explicit de

V. M. Tkachuk, P. Roy

We study one dimensional supersymmetric (SUSY) quantum mechanics of a spin 1/2 particle moving in a rotating magnetic field and scalar potential. We also discuss SUSY breaking and it is shown that SUSY breaking essentially depends on the strength and period of the magnetic field. For a purely rotating magnetic field the eigenvalue problem is solved exactly a

N. N. Nikolaev

In a consistent QCD approach to diffractive DIS gluons in the pomeron have soft $z_{g}$ distribution and very broad intrinsic $k_{\perp}$ distribution. The latter has not yet been incorporated into diffractive Monte-Carlo generators (RAPGAP,....). I argue that the so-introduced bias in the diffractive jet analysis may be the reason why H1 Collaboration finds

N. N. Nikolaev

I review the recent progress in the theory of s-channel helicity nonconservation (SCHNC) effects in diffractive DIS including the unitarity driven demise of the Burkhardt-Cottingham sum rule and strong scaling departure from the Wandzura-Wilczek relation.

Noboru Kawamoto, Takuya Tsukioka

We investigate the generalized gauge theory which has been proposed previously and show that in two dimensions the instanton gauge fixing of the generalized topological Yang-Mills action leads to a twisted N=2 supersymmetric action. We have found that the R-symmetry of N=2 supersymmetry can be identified with the flavour symmetry of Dirac-Kahler fermion form

Claudio Donati, Silvio Franz, Giorgio Parisi, Sharon C. Glotzer

Within the framework of the effective potential theory of the structural glass transition, we calculate for the p-spin model a static nonlinear susceptibility related to a four-point density correlation function, and show that it grows and diverges in mean field with exponent $\gamma=1/2$ as the mode coupling critical temperature T_c is approached from below

Alessandro D. A. M. Spallicci

An analytic solution of the Regge-Wheeler (RW) equation has been found via the Frobenius method at the regular singularity of the horizon 2M, in the form of a time and radial coordinate dependent series. The RW partial differential equation, derived from the Einstein field equations, represents the first order perturbations of the Schwarzschild metric. The k

Joao Magueijo, Kim Baskerville

We describe how cosmology has converged towards a beautiful model of the Universe: the Big Bang Universe. We praise this model, but show there is a dark side to it. This dark side is usually called ``the cosmological problems'': a set of coincidences and fine tuning features required for the Big Bang Universe to be possible. After reviewing these ``riddles''

M. Tentyukov, J. Fleischer

A C-program DIANA (DIagram ANAlyser) for the automatic Feynman diagram evaluation is presented.

M. Miyama

We discuss transversity distributions and Drell-Yan transverse double spin asymmetries. First, the antiquark flavor asymmetry $\Delta_{_T} \bar u/\Delta_{_T} \bar d$ is discussed by using two different descriptions, a meson-cloud model and a Pauli exclusion model. We find that both calculations produce a significant $\Delta_{_T} \bar d$ excess over $\Delta_{

Jan Kalinowski

A procedure to determine the chargino mixing angles and, subsequently, the fundamental SUSY parameters M2, mu and tan(beta) by measurements of the total cross section and the spin correlations in e+e- annihilation to chi1^+ chi1^- chargino pairs is discussed.

V. Pascalutsa, R. G. E. Timmermans

We discuss the nucleon to higher-spin $N$- and $\Delta$-resonance transitions by pions and photons. The higher-spin baryons are described by Rarita-Schwinger fields and, as we argue, this imposes a stringent consistency requirement on the form of the couplings. Popular $\pi N\Delta$ and $\gamma N\Delta$ couplings are inconsistent from this point of view. We

J. R. Forshaw

The study of those rapidity gap processes where a large momentum is transferred across the rapidity gap provides an ideal opportunity to understand the gap producing mechanism wholly within the framework of QCD perturbation theory. The current theoretical and experimental status of this `high-t diffraction' is reviewed.

Wolfgang Lucha, F. F. Schoberl

Motivated by a recent analysis which presents explicitly the general solution, we consider the eigenvalue problem of the spinless Salpeter equation with a ("hard-core amended") Coulomb potential in one dimension. We prove the existence of a critical coupling constant (which contradicts the assertions of the previous analysis) and give analytic upper bounds o

Naoki Bessho, Yukiharu Ohsawa

Electron motion in an oblique shock wave is studied by means of a one-dimensional, relativistic, electromagnetic, particle simulation code with full ion and electron dynamics. It is found that an oblique shock can produce electrons with ultra-relativistic energies; Lorentz factors with $\gamma \gto 100$ have been observed in our simulations. The physical mec

S. Seshadri, V. Balakrishnan, S. Lakshmibala

We present, for the isospectral family of oscillator Hamiltonians, a systematic procedure for constructing raising and lowering operators satisfying any prescribed `distorted' Heisenberg algebra (including the $q$-generalization). This is done by means of an operator transformation implemented by a shift operator. The latter is obtained by solving an appropr

J. Ortner, F. Schautz, W. Ebeling

Results of quasi-classical molecular dynamics simulations of the quantum electron gas are reported. Quantum effects corresponding to the Pauli and the Heisenberg principle are modeled by an effective momentum-dependent Hamiltonian. The velocity autocorrelation functions and the dynamic structure factors have been computed. A comparison with theoretical predi

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

We estimate the differential and total cross sections for both the photoproduction of vector D*-meson and its yield in deep inelastic scattering at the HERA collider in the framework of model motivated by perturbative calculations in QCD. The offered model allows us to take into account higher twists over the transverse momentum of meson at p_T ~ m_c and to

JLQCD Collaboration, K-I. Ishikawa, N. Yamada, S. Aoki

We present a lattice NRQCD study of the B meson decay constant in the quenched approximation with emphasis given to the scaling behavior. The NRQCD action and the heavy-light axial current we use include all terms of order 1/M and the perturbative $O(\alpha_s a)$ and $O(\alpha_s/M)$ corrections. Using simulations at three value of couplings $\beta$=5.7, 5.9

C. Chandre, H. R. Jauslin

We analyze the stability of invariant tori for Hamiltonian systems with two degrees of freedom by constructing a transformation that combines Kolmogorov-Arnold-Moser theory and renormalization-group techniques. This transformation is based on the continued fraction expansion of the frequency of the torus. We apply this transformation numerically for arbitrar

H. Jung

Predictions of the CCFM evolution equation for F_2 and forward jets at HERA energies are obtained from a modified version of the Monte Carlo program SMALLX. The treatment of the non-Sudakov form factor $\Delta_{ns}$ is discussed as well as the effect of the so called "consistency constraint". For the first time a good description of F_2 and the forward jet d

Mieko Toida, Daiju Dogen, Yukiharu Ohsawa

Low-frequency mangnetosonic pulses in a two-ion-species plasma are studied theoretically and by simulation with a one-dimensional electromagnetic simulation code based on a three-fluid model, with particular attention to the dynamics of minority heavy ions. It is found that heavy ions can gain some energy from the pulses. Because of this energy transfer, the

Hiroshi Suzuki

We present a regularization scheme which respects the supersymmetry and the maximal background gauge covariance in supersymmetric chiral gauge theories. When the anomaly cancellation condition is satisfied, the effective action in the superfield background field method automatically restores the gauge invariance without counterterms. The scheme also provides

L. Mangiarotti, G. Sardanashvily

We show that any second order dynamic equation on a configuration space $X\to R$ of nonrelativistic mechanics can be seen as a geodesic equation with respect to some (nonlinear) connection on the tangent bundle $TX\to X$ of relativistic velocities. We compare relativistic and nonrelativistic geodesic equations, and study the Jacobi vector fields along nonrel

Noam D. Elkies

A "still Life" is a subset S of the square lattice Z^2 fixed under the transition rule of Conway's Game of Life, i.e. a subset satisfying the following three conditions: 1. No element of Z^2-S has exactly three neighbors in S; 2. Every element of S has at least two neighbors in S; 3. Every element of S has at most three neighbors in S. Here a ``neighbor'' of

Gregory Adkins, Kirill Melnikov, Alexander Yelkhovsky

Order alpha^2 contribution to the orthopositronium decay rate due to one-photon virtual annihilation is found to be delta Gamma = (alpha/pi)^2 (pi^2 ln(alpha) - 0.8622(9))Gamma_LO.

C. Balazs, P. Nadolsky, C. Schmidt, C. -P. Yuan

The detection and the measurement of the production cross section of a light Higgs boson at the CERN Large Hadron Collider demand the accurate prediction of the background distributions of photon pairs. To improve this theoretical prediction, we present the soft-gluon resummed calculation of the $p p \to \gamma \gamma X$ cross section, including the exact on

Noam D. Elkies

It is one of the wonderful ``coincidences'' of the theory of finite groups that the simple group G of order 25920 arises as both a symplectic group in characteristic 3 and a unitary group in characteristic 2. These two realizations of G yield two G-covers of the moduli space of configurations of six points on the projective line modulo PGL_2, via the 3- and

Kanehisa Takasaki

We review new aspects of integrable systems discovered recently in N=2 supersymmetric gauge theories and their topologically twisted versions. The main topics are (i) an explicit construction of Whitham deformations of the Seiberg-Witten curves for classical gauge groups, (ii) its application to contact terms in the u-plane integral of topologically twisted

M. B. Tully, G. C. Joshi

Mass bounds for doubly-charged bilepton gauge bosons are derived from constraints on fermion pair production at LEP and lepton-flavour violating charged lepton decays. The limit obtained of 700 GeV for the doubly-charged bilepton does not depend on the bilepton coupling being flavour-diagonal, unlike other bounds which have been given in the literature.

Arthur Lue, Erick J. Weinberg

We present new analytic and numerical results for self-gravitating SU(2)-Higgs magnetic monopoles approaching the black hole threshold. Our investigation extends to large Higgs self-coupling, lambda, a regime heretofore unexplored. When lambda is small, the critical solution where a horizon first appears is extremal Reissner-Nordstrom outside the horizon but

H. Cendra, D. D. Holm, J. E. Marsden, T. S. Ratiu

There is a well developed and useful theory of Hamiltonian reduction for semidirect products, which applies to examples such as the heavy top, compressible fluids and MHD, which are governed by Lie-Poisson type equations. In this paper we study the Lagrangian analogue of this process and link it with the general theory of Lagrangian reduction; that is the re

G. Yepes, D. Elizondo, Y. Ascasibar

From a set of 3D cosmological simulations which incorporate a self-consistent model of the star-gas interactions, we have been able to obtain a statistically significant sample of galaxy-type halos with observational properties, like colors and luminosities. Using this data-base, we have studied general relations of galaxies, such as the Tully-Fisher relatio

A. D. Schwope, R. Schwarz, J. Greiner

We present a low-resolution discovery spectrum and CCD-photometry of the bright X-ray source 1RXS J012851.9-233931 found in the ROSAT All-Sky Survey. These first observations suggest that the source is an AM Herculis star (polar) accreting at a low rate. The optical spectrum is dominated by Zeeman absorption features from the white dwarf, indicating a mean p

SDSS Collaboration, Michael A. Strauss

We report the discovery of the coolest field dwarf yet known, selected as a stellar object with extremely red colors from commissioning imaging data of the Sloan Digital Sky Survey. Its spectrum from 0.8 to 2.5 microns is dominated by strong bands of H_2 O and CH_4. Its spectrum and colors over this range are very similar to those of Gliese 229B, the only ot

A. H. Hoang

The bottom quark 1S mass, $M_b^{1S}$, is determined using sum rules which relate the masses and the electronic decay widths of the $\Upsilon$ mesons to moments of the vacuum polarization function. The 1S mass is defined as half the perturbative mass of a fictitious ${}^3S_1$ bottom-antibottom quark bound state, and is free of the ambiguity of order $\Lambda_

D. -Q. Zhang

Let X be a K3 surface with an involution g which has non-empty fixed locus X^g and acts non-trivially on a non-zero holomorphic 2-form. We shall construct all such pairs (X, g) in a canonical way, from some better known double coverings of log del Pezzo surfaces of index at most 2 or rational elliptic surfaces, and construct the only family of each of the th

Ping Xu

We introduce a general notion of quantum universal enveloping algebroids (QUE algebroids), or quantum groupoids, as a unification of quantum groups and star-products. Some basic properties are studied including the twist construction and the classical limits. In particular, we show that a quantum groupoid naturally gives rise to a Lie bialgebroid as a classi

Aseshkrishna Datta, Biswarup Mukhopadhyaya, Sourov Roy

The constraints on an R-parity violating supersymmetric theory arising from the recent SuperKamiokande results on atmospheric neutrinos are studied, with special reference to a scenario with bilinear R-parity violating terms. Considering both the fermionic and scalar sectors, we find that a large area of the parameter space is allowed, in terms of both the l

George Sterman

The past few years have seen remarkable progress in the theory and phenomenology of QCD, bringing perturbative and nonperturbative methods into closer contact with each other and with experiment.

Yorck Sommerhaeuser

We prove a structure theorem for Yetter-Drinfel'd Hopf algebras over groups of prime order that are nontrivial, cocommutative, and cosemisimple: Under certain assumptions on the base field, these algebras can be decomposed into a tensor product of the dual group ring of the group of prime order and an ordinary group ring of some other group. This tensor prod

Charles Francis

An interpretation and re-formulation of modern physics which removes the presumption of the space-time continuum, and bases physical theory on a small number of rational and empirical principles. After briefly describing the philosophical principles underlying the theory, we rigorously construct a discrete model of quantum mechanics. Kets are names, or label

Hanoch Mehl, Ofer Biham, Oded Millo, Majid Karimi

Electromigration-induced flow of islands and voids on the Cu(001) surface is studied at the atomic scale. The basic drift mechanisms are identified using a complete set of energy barriers for adatom hopping on the Cu(001) surface, combined with kinetic Monte Carlo simulations. The energy barriers are calculated by the embedded atom method, and parameterized

P. Baseilhac, V. A. Fateev

We introduce and study one parameter family of integrable quantum field theories. This family has a Lagrangian description in terms of massive Thirring fermions $\psi,\psi^{\dagger}$ and charged bosons $\chi,\bar{\chi}$ of complex sinh-Gordon model coupled with $BC_n$ affine Toda theory. Perturbative calculations, analysis of the factorized scattering theory

Vladimir O. Soloviev

Recently it has been suggested by S. Carlip that black hole entropy can be derived from a central charge of the Virasoro algebra arising as a subalgebra in the surface deformations of General Relativity in any dimension. Here it is shown that the argumentation given in Section 2 of hep-th/9812013 and based on the Regge-Teitelboim approach is unsatisfactory.

K. Suzuki, E. Hiyama, H. Toki, M. Kamimura

We study the roles of quark-pair correlations for baryon properties, in particular on non-leptonic weak decay of hyperons. We construct the quark wave function of baryons by solving the three body problem explicitly with confinement force and the short range attraction for a pair of quarks with their total spin being 0. We show that the existence of the stro

A. M. Vershik, S. Nechaev, R. Bikbov

Statistical and probabilistic characteristics of locally free group with growing number of generators are defined and their application to statistics of braid groups is given.

Yu-Ping Kuang

Recent developments of physics at the TeV energy scale, especially physics related to the electron-positron linear colliders are briefly reviewed. The topics include the present status of the standard model, Higgs physics, supersymmetry, strongly interacting electroweak symmetry breaking mechanism, and top quark physics.

S. Frixione

After a short discussion on the definition of isolated-photon cross sections in perturbative QCD, I present phenomenological predictions relevant for polarized hadron-hadron collisions in the RHIC energy range. The possibility of measuring $\Delta g$ is investigated.

S. Frixione

I present a review of selected topics in the computation of heavy flavour cross sections in photon-hadron collisions.

S. Kalyana Rama, B. Sathiapalan

The question of how infalling matter in a pure state forms a Schwarzschild black hole that appears to be at non-zero temperature is discussed in the context of the AdS/CFT connection. It is argued that the phenomenon of self-thermalization in non-linear (chaotic) systems can be invoked to explain how the boundary theory, initially at zero temperature self th

Masahiro Imachi, Shouhei Kanou, Hiroshi Yoneyama

Topological charge distributions in 2 dimensional CP^2 model with theta-term is calculated. In strong coupling regions, topological charge distribution is approximately given by Gaussian form as a function of topological charge and this behavior leads to the first order phase transition at \theta=\pi. In weak coupling regions it shows non-Gaussian distributi

Robert Shrock, Shan-Ho Tsai

We present exact calculations of chromatic polynomials for families of cyclic graphs consisting of linked polygons, where the polygons may be adjacent or separated by a given number of bonds. From these we calculate the (exponential of the) ground state entropy, $W$, for the q-state Potts model on these graphs in the limit of infinitely many vertices. A numb

P. J. E. Peebles

One way to judge the impact of the inflation concept is to consider where cosmology might be today without it. The Einstein-de Sitter model would not have been so keenly defended, and there might have been more interest in negative space curvature, but the observations would have driven us to about where we are. We would have had much the same ideas about st

Alexei Borodin, Grigori Olshanski

We suggest an hierarchy of all the results known so far about the connection of the asymptotics of combinatorial or representation theoretic problems with ``beta=2 ensembles'' arising in the random matrix theory. We show that all such results are, essentially, degenerations of one general situation arising from so-called generalized regular representations o

Luis A. Cordero, Phillip E. Parker

We begin a systematic study of these spaces, initially following along the lines of Eberlein's comprehensive study of the Riemannian case. In particular, we integrate the geodesic equation, discuss the structure of the isometry group, and make a study of lattices and periodic geodesics. Some major differences from the Riemannian theory appear. There are many

Jonathan Gratus

A noncommutative algebra $A$, called an algebraic noncommutative geometry, is defined, with a parameter $\epsilon$ in the centre. When $\epsilon$ is set to zero, the commutative algebra $A^0$ of algebraic functions on an algebraic manifold $M$ is obtained. This $A^0$ is a subalgebra of $C(M)$, which is dense if $M$ is compact. The generators of $A$ define an

Daniel Brace, Bogdan Morariu, Bruno Zumino

We present an Sp(2n,R) duality invariant Born-Infeld U(1)^2n gauge theory with scalar fields. To implement this duality we had to introduce complex gauge fields and as a result the rank of the duality group is only half as large as that of the corresponding Maxwell gauge theory with the same number of gauge fields. The latter is self-dual under Sp(4n,R), the

Lior M. Burko

We discuss a piecewise-conserved constant of motion for a simple dissipative oscillatory mechanical system. The system is a harmonic oscillator with sliding (dry) friction. The piecewise-conserved constant of motion corresponds to the time average of the energy of the system during one half-period of the motion, and changes abruptly at the turning points of

O. Martin

We calculate the transverse double-spin asymmetry for the production of dimuons in pp collisions as function of the dimuon rapidity and mass to next-to-leading accuracy in the strong coupling. Predictions for BNL-RHIC and HERA-N are made by assuming a saturation of Soffer's inequality at a low hadronic input scale. It seems unlikely that transversity can be

Gordon Baym, Jean-Paul Blaizot, Markus Holzmann, Franck Laloë

We show that the critical temperature of a uniform dilute Bose gas must increase linearly with the s-wave scattering length describing the repulsion between the particles. Because of infrared divergences, the magnitude of the shift cannot be obtained from perturbation theory, even in the weak coupling regime; rather, it is proportional to the size of the cri