July 1999 arXiv papers — page 15

R. Walsh, A. J. Ramalho

We discuss possible deviations from QED produced by a virtual excited spin-3/2 lepton in the reaction $e^+e^- \longrightarrow 2γ$. Data recorded by the OPAL Collaboration at a c.m. energy $\sqrt{s} = 183 GeV$ are used to establish bounds on the nonstandard-lepton mass and coupling strengths.

Junegone Chay, Adam F. Falk, Michael Luke, Alexey A. Petrov

We explore the theoretical feasibility of extracting V_ub from two ratios built from B meson inclusive partial decays, R_1 = Gamma(b-> u cbar s)/3Gamma(b -> c l nu), and R_2 = [Gamma(b -> c X) - Gamma(b -> cbar X)]/Gamma(b -> c ubar d). We discuss contributions to these quantities from perturbative and nonperturbative physics, and show that they can be compu

Christopher D. Carone

Electroweak measurements place significant bounds on higher-dimensional versions of the standard model in which the gauge and Higgs fields have Kaluza-Klein excitations. These bounds may be altered quantitatively if chiral matter is also allowed to propagate in the higher-dimensional `bulk'. We determine the electroweak constraints on a number of models

B. Holdom

The consideration of chirality-preserving 2-fermion order parameters may shed new light on the strong CP problem and the breakdown of flavor symmetries. We describe two situations, one having the standard KM picture for weak CP violation and another having new sources of weak CP violation.

J. -L. Kneur, G. Moultaka

We consider recovering analytically the (generally complex) parameters $μ$, $M_1$ and $M_2$ of the gaugino and Higgsino Lagrangian, from appropriate physical input in the chargino and neutralino sectors. For given $\tanβ$, we obtain very simple analytic solutions for $M_2$, $| μ|$, $Arg[μ]$ in the chargino sector and a twofold $| M_1 |$, $Arg[M_1]$ analytic

Mike Bisset, Otto C. W. Kong, Cosmin Macesanu, Lynne H. Orr

We present a study of charged lepton mass matrix diagonalization in R-parity violating SUSY. The case in which the bilinear couplings $μ_i$ have large values is given special attention.

Stefano Catani, Michael H. Seymour

We have recently calculated the second-order QCD corrections to the forward-backward asymmetry in e+e- annihilation (hep-ph/9905424). Here we recall the results and compare them to others in the literature.

P. J. Mulders, M. Boglione

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

M. R. Pennington

The physics that can be learnt by studying exclusive channels in two photon interactions is recalled. This serves as an introduction to the Exclusive Reaction session of Photon'99.

J. Dias de Deus, R. Ugoccioni, A. Rodrigues

We present a simple model with string absorption and percolation to describe the J/psi suppression in heavy ion collisions. The NA50 data are fairly well explained by the model.

Alekhin Sergey

We perform a NLO QCD analysis of the nonsinglet part of the combined SLAC-BCDMS-NMC data on inclusive deep inelastic cross section with the extraction of $α_s$. We show that the value of $α_s$ obtained in the analysis is sensitive to the statistical inference procedures dealing with systematic errors on the data. The fit with the complete account of point-to

N. Suzuki, M. Biyajima

Identical particle correlations at fixed multiplicity are consideres in the presence of chaotic and coherent fields. The multiplicity distribution, one-particle momentum density, and two-particle correlation function are obtained based on the diagrammatic representation for cmulants in semi-inclusive events. Our formulation is applied to the analysis of the

A. Airapetian

We present a measurement of the longitudinal spin asymmetry A_|| in photoproduction of pairs of hadrons with high transverse momentum p_T. Data were accumulated by the HERMES experiment using a 27.5 GeV polarized positron beam and a polarized hydrogen target internal to the HERA storage ring. For h+h- pairs with p_T^h_1 > 1.5 GeV/c and p_T^h_2 > 1.0 GeV/c, t

A. V. Kopylov

The high sensitivity of lithium detector to pep- and Be7-neutrinos makes a lithium radiochemical detector a powerful tool for the search of the oscillations of solar neutrinos. The first phase of lithium experiment on the installation with 10 tons of metallic lithium will enable to collect data within 1 year of measurements to provide very definite informati

M. B. Golubev

This paper deals with the problem of a point-like charged source under the influence of the external electromagnetic field in terms of perturbation theory for GR equations. It is obtained that GR, in contrast with the classical electrodynamics, in linear perturbation theory predicts an unlimited growth of the dipole perturbation. It is shown that the reason

S. V. Chervon, V. M. Zhuravlev

A cosmological model of homogeneous and isotropic spatially flat Universe with gravitating self-interacting scalar field is considered. The exact solution, admitting an analytical exit from inflationary stage into a radiation era and a matter dominated epoch, is obtained by virtue of ``fine turning of the potential'' method. We found that an inflatio

Luca Lusanna, Stefano Russo

After a study of the Hamiltonian group of gauge transformations of canonical tetrad gravity on globally hyperbolic, asymptotically flat at spatial infinity, spacetimes with Cauchy hypersurfaces $Σ_τ$ diffeomorphic to $R^3, we find the dependence of the cotriads on $Σ_τ$ and of their momenta on the six parameters associated with rotations and space diffeomorp

Luca Lusanna, Stefano Russo

A new version of tetrad gravity in globally hyperbolic, asymptotically flat at spatial infinity spacetimes with Cauchy surfaces diffeomorphic to $R^3$ is obtained by using a new parametrization of arbitrary cotetrads to define a set of configurational variables to be used in the ADM metric action. Seven of the fourteen first class constraints have the form o

J. Cerne, D. C. Schmadel, M. Grayson, G. S. Jenkins

A sensitive mid-infrared (MIR, 900-1100 cm-1, 112-136 meV) photo-elastic polarization modulation technique is used to measure simultaneously Faraday rotation and circular dichroism in thin metal films. These two quantities determine the complex AC Hall conductivity. This novel technique is applied to study Au and Cu thin films at temperatures down to 20 K an

M. N. Tamashiro, P. Pincus

We consider the interactions between two uncharged planar macroscopic surfaces immersed in an electrolyte solution which are induced by interfacial selectivity. These forces are taken into account by introducing a depletion free-energy density functional, in addition to the usual mean-field Poisson-Boltzmann functional. The minimization of the total free-ene

Shirish M. Chitanvis

We consider the case when a supercritical fluid emerges at sonic speed from a small orifice in a high pressure chamber. The subsequent expansion causes a pressure drop and the fluid then enters a regime where its equation of state in $P-V$ space becomes concave towards the origin. This is the signal for an expansion shock to occur in a non-ideal fluid. This

Reinhard Baltin, Yuval Gefen

We study the phase of the transmission amplitude through a disordered quantum dot in the Coulomb blockade regime. We calculate the phase dependence on gate voltage for a disorder configuration. We show that over a ``period'', consisting of a resonance and a transmission valley, the total phase change is 0 (mod $2π$). Deviations from this sum rule are

M. A. Cazalilla, J. S. Dolado, A. Rubio, P. M. Echenique

The delicate interplay between plasmonic excitations and interband transitions in noble metals is described by means of {\it ab initio} calculations and a simple model in which the conduction electron plasmon is coupled to the continuum of electron-hole pairs. Band structure effects, specially the energy at which the excitation of the $d$-like bands takes pl

N. V. Prokof'ev, B. V. Svistunov

We point out that two different definitions of the superfluid density - through statistical response to static gauge phase and through dynamic response to altering gauge phase - yield, generally speaking, different quantities in $d<3$. The physics leading to this difference is associated with the equilibrium statistics of supercurrent states. Some experiment

Hui Li, Dimitri Kusnezov

The group theoretical treatment of bound and scattering state problems is extended to include band structure. We show that one can realize Hamiltonians with periodic potentials as dynamical symmetries, where representation theory provides analytic solutions, or which can be treated with more general spectrum generating algebraic methods. We find dynamical sy

Yue Yu

Based on the composite fermion approach, we derive a microscopic theory describing the low-lying edge excitations in the fractional quantum Hall liquid with $ν=\frac{ν^*}{\tildeϕν^*+1}$. For $ν^*>0$, it is found that the composite fermion model reduces to an SU$(ν^*)$ Calogero-Sutherland model in the one-dimensional limit, whereas it is not exact soluble for

R. J. R. Williams, A. C. Baker, J. J. Perry

Compelling evidence associates the nuclei of active galaxies and massive starbursts. The symbiosis between a compact nuclear starburst stellar cluster and a massive black hole can self-consistently explain the properties of active nuclei. The young stellar cluster has a profound effect on the most important observable properties of active galaxies through it

Philip R. Maloney, J. Bland-Hawthorn

Several lines of argument suggest that a large fraction of the baryons in the universe may be in the form of warm (T\sim 10^5-10^7 K) gas. In particular, loose groups of galaxies may contain substantial reservoirs of such gas. Observations of the cosmic microwave background by COBE place only weak constraints on such an intragroup medium within the Local Gro

Andrew J. Bunker

The increased incidence of morphologically peculiar galaxies at faint magnitudes in the optical could be attributable either to &#34;morphological k-corrections&#34; (the change in appearance when viewing high-z objects at shorter rest-frame wavelengths), or an increase in the incidence of truly irregular systems with redshift. The deep, high-resolution GTO-

David Charbonneau, Robert W. Noyes, Sylvain G. Korzennik, Peter Nisenson

The planet orbiting tau Boo at a separation of 0.046 AU could produce a reflected light flux as bright as 1e-4 relative to that of the star. A spectrum of the system will contain a reflected light component which varies in amplitude and Doppler-shift as the planet orbits the star. Assuming the secondary spectrum is primarily the reflected stellar spectrum, w

Peter H. Hauschildt, France Allard, Jason Ferguson, E. Baron

We present the extension of our NextGen model atmosphere grid to the regime of giant stars. The input physics of the models presented here is nearly identical to the NextGen dwarf atmosphere models, however spherical geometry is used self-consistently in the model calculations (including the radiative transfer). We re-visit the discussion of the effects of s

K. Nandra, I. M. George, R. F. Mushotzky, T. J. Turner

We present an analysis of the relativistic iron K-alpha line in the Seyfert 1 galaxy NGC 3516, based on a continuous, five-day ASCA observation. The broad profile which has been found in several other AGN is confirmed in NGC 3516 with unprecedented signal-to-noise ratio. Disk-line models with either a Kerr or Schwarzschild metric fit the integrated profile,

K. Nandra

Several X-ray properties of active galactic nuclei depend, or appear to depend, on their luminosity. It has long been suggested that alpha o-x, the X-ray ``loudness&#39;&#39; decreases with luminosity. There never has been a satisfactory explanation of this observational claim, and the statistical soundness of the result has been disputed. The earliest syste

F. Meyer, E. Meyer-Hofmeister

The white dwarf in AM Her systems is strongly magnetic and keeps in synchronous rotation with the orbit by magnetic coupling to the secondary star. As the latter evolves through mass loss to a cool, degenerate brown dwarf it can no longer sustain its own magnetic field and coupling is lost. Angular momentum accreted then spins up the white dwarf and the syst

B. Ciardi, A. Ferrara, F. Governato, A. Jenkins

We study the inhomogeneous reionization in a critical density CDM universe due to stellar sources, including Population III objects. The spatial distribution of the sources is obtained from high resolution numerical N-body simulations. We calculate the source properties taking into account a self-consistent treatment of both radiative (ie ionizing and H2 -ph

John P. Grimes, Gerard A. Kriss, Brian R. Espey

We present spatially resolved far-UV spectra (912-1840 A) of NGC 1068 obtained using the Hopkins Ultraviolet Telescope (HUT) during the March 1995 Astro-2 mission. Three spectra of this prototypical Seyfert 2 galaxy were obtained through a 12 arcsec diameter aperture centered on different locations near the nucleus. The first pointing (A1) was centered west

Abraham Loeb

The formation of the first stars and quasars marks the transition between the smooth initial state and the clumpy current state of the Universe. In popular CDM cosmologies, the first sources of light started to form at a redshift z=30 and ionized most of the hydrogen in the Universe by z=8. Current observations are at the threshold of probing the reionizatio

John P. Hughes

Four individual high resolution X-ray images from ROSAT and the Einstein Observatory have been used to measure the expansion rate of the remnant of Kepler&#39;s supernova (SN 1604). Highly significant measurements of the expansion have been made for time baselines varying from 5.5 yrs to 17.5 yrs. All measurements are consistent with a current expansion rate

Penny D. Sackett

Massive gravitational microlensing programs were begun about a decade ago as a means to search for compact baryonic dark matter in the Galaxy, but before the first events were detected the technique was also proposed as a means of detecting extra-solar planets in our Galaxy. Current microlensing planet searches, which have been underway for four years, are s

C. F. Quist, L. Lindegren

The Hipparcos Transit Data are a collection of partially reduced, fully calibrated observations of (mostly) double and multiple stars obtained with the ESA Hipparcos astrometry satellite. The data are publicly available, as part of the CD-ROM set distributed with the Hipparcos and Tycho Catalogues (ESA SP--1200, 1997), for about a third of the Hipparcos Cata

Jacco Th. van Loon, F. J. Molster, Hans van Winckel, L. B. F. M. Waters

We present new imaging and spectroscopy of the post-red supergiant binary AFGL 4106. Coronographic imaging in H-alpha reveals the shape and extent of the ionized region in the circumstellar envelope (CSE). Echelle spectroscopy with the slit covering almost the entire extent of the CSE is used to derive the physical conditions in the ionized region and the op

Dainis Dravins, Lennart Lindegren, Soren Madsen

High-accuracy astrometry permits the determination of not only stellar tangential motion, but also the component along the line-of-sight. Such non-spectroscopic (i.e. astrometric) radial velocities are independent of stellar atmospheric dynamics, spectral complexity and variability, as well as of gravitational redshift. Three methods are analysed: (1) changi

Maria de Sousa Vieira

We introduce a new continuous cellular automaton that presents self-organized criticality. It is one-dimensional, totally deterministic, without any kind of embedded randomness, not even in the initial conditions. This system is in the same universality class as the Oslo rice pile system, boundary driven interface depinning and the train model for earthquake

M. V. Chistyakov, N. V. Mikheev

The influence of strongly magnetized electron-positron plasma on the radiative neutrino transition $\nng$ is investigated. The probability and mean losses of the neutrino energy and momentum are calculated taking account of the photon dispersion and large radiative corrections near the resonance. It is shown that the combined effect of plasma and strong magn

Jon Loveday

We present a measurement of the K-band luminosity function (LF) of field galaxies obtained from near-infrared imaging of a sample of 345 galaxies selected from the Stromlo-APM Redshift Survey. The LF is well-fitted over the ten magnitude range -26 < M_K < -16 by a Schechter function with parameters alpha = -1.16 +- 0.19, M* = -23.58 +- 0.42, phi* = 0.012 +-

Micha Berkooz, Herman Verlinde

We discuss the relation between the Matrix theory definitions of a class of decoupled theories and their AdS/CFT description in terms of the corresponding near-horizon geometry. The near horizon geometry, naively part of the Coulomb branch, is embedded in the Higgs branch via a natural change of variables. The principles of the map apply to all DLCQ descript

V. Cirigliano, J. Donoghue, E. Golowich

An analysis of electromagnetic corrections to the (dominant) octet K -> pi pi hamiltonian using chiral perturbation theory is carried out. Relative shifts in amplitudes at the several per cent level are found.

Tommaso Treu, Massimo Stiavelli

We have collected optical follow-up observations from the ground and the Hubble Space Telescope (HST) for 13.74 square &#39; of archival images taken with the Near Infrared Camera and Multi Object Spectrograph (NICMOS). We use two criteria to select E/S0 galaxy candidates at z>~1 and z>~1.5 (HizECs) based on colors and infrared morphology. The observed surfa

Frank Wilczek

I discuss why QCD is our most perfect physical theory. Then I visit a few of its current frontiers. Finally I draw some appropriate conclusions.

Brent R. Boyce, Kathleen M. Paget, Thomas R. Lemberger

We report measurements of the magnetic penetration depth in YBCO films at various oxygen concentrations. At optimal doping, critical fluctuation effects are absent, and the penetration depth from 4 K to 0.99 Tc is well described by d-wave, BCS, strong-coupling theory with a gap, Delta0/ kT ~ 3.3. This implies that the T-dependence of the penetration depth co

Jason Tumlinson, Mark L. Giroux, J. Michael Shull, John T. Stocke

We present UV spectroscopy from HST/GHRS and reanalyze existing H_alpha images of the quasar/galaxy pair 3C 232/NGC 3067 and of the halo gas associated with NGC 3067. The spectra permit measurement of, or limits on, the column densities of Fe I, Fe II, Mg I, and Mg II in the absorbing cloud. Two distinct models of the extragalactic radiation field are consid

D. G. Barci, Cesar A. Linhares, J. F. Medeiros Neto, A. F. de Queiroz

We analyze the universality of the bosonization rules in non-relativistic fermionic systems in $(2+1)d$. We show that, in the case of linear fermionic dispersion relations, a general fermionic theory can be mapped into a gauge theory in such a way that the fermionic density maps into a magnetic flux and the fermionic current maps into a transverse electric f

Laurent Baulieu, Celine Laroche, Nikita Nekrasov

We address the issue of the worldsheet and spacetime covariant formulation for matrix strings. The problem is solved in the limit of vanishing string coupling. To go beyond the g_s = 0 limit, we propose a topological quantum field theory as a twisted candidate. Our model involves the generalized octonionic or SU(4) instanton equations defined in eight dimens

Mei-Rong Li, P. J. Hirschfeld, P. Woelfle

We investigate the free energy and the penetration depth of a quasi-two-dimensional d-wave superconductor in the presence of a weak magnetic field by taking account of thermal, nonlocal and nonlinear effects. In an approximation in which the superfluid velocity $v_s$ is assumed to be slowly varying, the free energy is calculated and compared with available r

Rainer Hegger, Martin J. Bünner, Holger Kantz, Antonino Giaquinta

Systems with delayed feedback can possess chaotic attractors with extremely high dimension, even if only a few physical degrees of freedom are involved. We propose a state space reconstruction from time series data of a scalar observable, coming along with a novel method to identify and model such systems, if a single variable is fed back. Making use of spec

Ulrika Magnea

We consider the parity-invariant Dirac operator with a mass term in three-dimensional QCD for $N_c=2$ and quarks in the fundamental representation. We show that there exists a basis in which the matrix elements of the Euclidean Dirac operator are real. Assuming there is spontaneous breaking of flavor and/or parity, we read off from the fermionic action the f

A. Gal

The relationship between the lower limit on the nuclear stability lifetime as derived from the non disappearance of `stable` nuclei ($T_{d}~\gtrsim~5.4~\times~10^{31}$ yr), and the lower limit thus implied on the oscillation time $(τ_{n \bar n})$ of a possibly underlying neutron-antineutron oscillation process, is clarified by studying the time evolution of

Yoji Michishita

We construct D0-branes in SO(32)$\times$SO(32) open type 0 string theory using the same method as the one used to construct non-BPS D0-brane in type I string theory. It has been proposed that this theory is S-dual to bosonic string theory compactified on SO(32) lattice, which has SO(32)$\times$SO(32) spinor states as excited states of fundamental string. One

R. C. Rashkov

In a recent paper Klebanov and Witten (hep-th/9905104) proposed to formulate the AdS/CFT correspondence principle by taking an &#34;irregular boundary condition&#34; for a scalar field. In this paper we generalize this idea to the case of spinor field with interaction. The action functional following from the choice of irregular boundary conditions and which

Wei Zhu, Jianhong Ruan

The coefficients of the nonlinear terms in a modified Altarelli-Parisi evolution equation with parton recombination are determined in the leading logarithmic ($Q^2$) approximation. The results are valid in the whole $x$ region and contain the translation $GG\to q\bar q$, which is inhibited in the double leading logarithmic approximation. The comparisons of t

Z. K. Silagadze

Lepton flavor violating decays $Z \to μτ$ and $J/Ψ, Υ\to μτ$ are considered. It is shown that these decays can reach sizeable magnitudes if some specific lepton-flavor violating 4-fermion operators are generated by low scale quantum gravity effects, or by some other new physics at a TeV scale.

AGAPE Collaboration, V. Bozza, S. Calchi Novati, M. Capaccioli

SLOTT-AGAPE (Systematic Lensing Observation at Toppo Telescope - Andromeda Gravitational Amplification Pixel Lensing Experiment) is a new collaboration project among international partners from England, France, Germany, Italy and Switzerland that intends to perform microlensing observation by using M31 as target. The MACHOs search is made thanks to the pixel

J. Fleischer, F. Jegerlehner, O. V. Tarasov

An algorithm for the reduction of one-loop n-point tensor integrals to basic integrals is proposed. We transform tensor integrals to scalar integrals with shifted dimension and reduce these by recurrence relations to integrals in generic dimension. Also the integration-by-parts method is used to reduce indices (powers of scalar propagators) of the scalar dia

Valerie Coffman, Joydip Kundu, William K. Wootters

Consider three qubits A, B, and C which may be entangled with each other. We show that there is a trade-off between A&#39;s entanglement with B and its entanglement with C. This relation is expressed in terms of a measure of entanglement called the &#34;tangle,&#34; which is related to the entanglement of formation. Specifically, we show that the tangle betw

Ulf-G. Meißner

Baryon form factors can be analyzed in a largely model-independent fashion in terms of two complementary approaches. These are chiral perturbation theory and dispersion relations. I review the status of dispersive calculations of the nucleon electromagnetic form factors in the light of new data. Then, I present the leading one-loop chiral perturbation theory

R. S. Bhalerao, Gouranga C. Nayak

Production and equilibration of quark-gluon plasma are studied within the color flux-tube model, at the RHIC and LHC energies. Non-Abelian relativistic transport equations for quarks, antiquarks and gluons, are solved in the extended phase space which includes coordinates, momenta and color. Before the chromoelectric field is formed, hard and semihard parton

Egor Babaev

The chiral Gross-Neveu model is one of the most popular toy models for QCD. In the past, it has been studied in detail in the large-N limit. In this paper we study its small-N behavior at finite temperature in 2+1 dimensions. We show that at small N the phase diagram of this model is {\it principally} different from its behavior at $N\to \infty$. We show tha

Cosma Rohilla Shalizi, James P. Crutchfield

Computational mechanics, an approach to structural complexity, defines a process's causal states and gives a procedure for finding them. We show that the causal-state representation--an $\epsilon$-machine--is the minimal one consistent with accurate prediction. We establish several results on $\epsilon$-machine optimality and uniqueness and on how $\epsilon$

V. Frolov, D. Fursaev

We develop a method for computing the free-energy of a canonical ensemble of quantum fields near the horizon of a rotating black hole. We show that the density of energy levels of a quantum field on a stationary background can be related to the density of levels of the same field on a fiducial static space-time. The effect of the rotation appears in the addi

A. S. Parkins, H. J. Kimble

We propose a scheme for preparing an EPR state in position and momentum of a pair of distantly-separated trapped atoms. The scheme utilizes the entangled light fields output from a nondegenerate optical parametric amplifier. Quantum state exchange between these fields and the motional states of the trapped atoms is accomplished via interactions in cavity QED

T. Opatrny, G. Kurizki, D. -G. Welsch

We show that the recently proposed scheme of teleportation of continuous variables [S.L. Braunstein and H.J. Kimble, Phys. Rev. Lett. 80, 869 (1998)] can be improved by a conditional measurement in the preparation of the entangled state shared by the sender and the recipient. The conditional measurement subtracts photons from the original entangled two-mode

J. Baehr, R. Nahnhauer, S. Nerreter, R. Shanidze

An intense 146 MeV/c pion beam was stopped inside a scintillating fiber detector made out of 12 planes with 16 pixels each, where every pixel consists out of 8 times 8 scintillating fibers of 500 mkm diameter dense packed. The detector was irradiated for 52 hours to more than 1 Mrad at its center. Before and directly after the irradiation the detector has be

E. C. Aschenauer, J. Baehr, R. Nahnhauer, R. Shanidze

Radiation hardness studies of KURARAY SCSF-78M scintillating fibers and clear fibers from KURARAY and pol.hi.tech. performed under different dose rate conditions in proton and electron beams are summarized. For high dose rates in-situ measurements of the fiber light output were done. During several months after irradiation all fibers were measured concerning

H. C. Rosu, J. Socorro

We replace the usual integral in the shape function of the synchrotron spectrum by a Jackson (q-deformed) integral and write down the formulas required to calculate the Jackson first deformed form of the synchrotron shape function

Troels C. Petersen, Jorgen Randrup

Using a semi-classical treatment of the linear sigma model, we simulate the dynamical evolution of an initially hot cylindrical rod endowed with a longitudinal Bjorken scaling expansion (a ``Bjorken rod&#39;&#39;). The field equation is propagated until full decoupling has occurred and the asymptotic many-body state of free pions is then obtained by a suitab

K. Suzuki, R. Okamoto, M. Kohno, S. Nagata

Exact expressions of the Pauli exclusion operator Q in the nuclear matter calculation are presented in detail. Exact formulae are also given for the calculations of the single-particle-potential energy and the binding energy per nucleon with the exact Q operator. Numerical calculations of the G matrix in the lowest-order Brueckner theory are carried out to c

WA98 Collaboration, H. Schlagheck

Directed and elliptic flow of protons and positively charged pions has been studied in the target fragmentation region using the Plastic Ball detector in the WA98 experiment. The results exhibit a strong dependence on centrality, rapidity, and transverse momentum. The rapidity dependence can be described by a Gaussian distribution. The model comparisons reve

Jacob Mostovoy, Theodore Stanford

We study a certain type of braid closure which resembles the plat closure but has certain advantages; for example, it maps pure braids to knots. The main results of this note are a Markov-type theorem and a description of how Vassiliev invariants behave under this braid closure.

Pieter Collins

Given a saddle fixed point of a surface diffeomorphism, its stable and unstable curves $W^S$ and $W^U$ often form a homoclinic tangle. Given such a tangle, we use topological methods to find periodic points of the diffeomorphism, using only a subset of the tangle with finitely many points of intersection, which we call a trellis. We typically obtain exponent

Michael K. Kinyon, Arthur A. Sagle

Given a Lie algebra $\frak{g}$, the \emph{Nahm algebra} of $\frak{g}$ is the vector space $\frak{g}\times \frak{g}\times \frak{g}$ with the natural commutative, nonassociative algebra structure associated with the Nahm equations $\dot{x} = [y,z]$, $\dot{y} = [z,x]$, $\dot{z} = [x,y]$. Motivated by potential application to the study of these equations, we her

Anne Heyworth, Christopher D Wensley

The key idea is that rewriting procedures can be enhanced so that they not only rewrite words but record (log) how the rewriting has taken place. We introduce logged rewrite systems and present a variation on the Knuth-Bendix algorithm for obtaining (where possible) complete logged rewrite systems. This procedure is then applied to work of Brown and Razak Sa

Thomas Peternell, Andrew J. Sommese

Given a covering f: X \to Y of projective manifolds, we consider the vector bundle E on Y given as the dual of f_*(Ø_X) / Ø_Y. This vector bundles often has positivity properties, e.g. E is ample when Y is projective space by a theorem of Lazarsfeld. In general however E will not be ample due to the geometry of Y. We prove various results when E is spanned,

Iosif Polterovich

We calculate heat invariants of arbitrary Riemannian manifolds without boundary. Every heat invariant is expressed in terms of powers of the Laplacian and the distance function. Our approach is based on a multi-dimensional generalization of the Agmon-Kannai method. An application to computation of the Korteweg-de Vries hierarchy is also presented.

Neil. D. Lambert, David Tong

We study two-dimensional SQED viewed as the world-volume theory of a D-string in the presence of D5-branes with non-zero background fields that induce attractive forces between the branes. In various approximations, the low-energy dynamics is given by a hyperKahler, or hyperKahler with torsion, massive sigma-model. We demonstrate the existence of kink soluti

V. V. Skalozub, A. Y. Tishchenko

Three-photon vertex in a dense degenerated plasma is calculated. It is discovered the polarization tensor has the longitudinal part which makes possible an interaction between transverse and longitudinal modes in the medium. Using dispersion relations it is shown that the only kinematically permitted type of the photon splitting is the decay of the transvers

James E. Lidsey

A theorem of differential geometry is employed to locally embed a wide class of superstring backgrounds that admit a covariantly constant null Killing vector field in eleven-dimensional, Ricci-flat spaces. Included in this class are exact type IIB superstring backgrounds with non-trivial Ramond-Ramond fields and a class of supersymmetric string waves. The em

Carlo Becchi, Renzo Collina

The aim of this paper is to give a firm and clear proof of the existence in the background field framework of a gauge invariant effective action for any gauge theory ({\it background gauge equivalence}). Here by effective action we mean a functional whose Legendre transform restricted to the physical shell generates the matrix elements of the connected $S$-m

Subir Ghosh

Three dimensional (abelian) gauged massive Thirring model is bosonized in the large fermion mass limit. A further integration of the gauge field results in a non-local theory. A truncated version of that is the Maxwell Chern Simons (MCS) theory with a conventional mass term or MCS Proca theory. This gauge invariant theory is completely solved in the Hamilton

Dongsu Bak, Kimyeong Lee, Piljin Yi

Classical properties of 1/4 BPS dyons were previously well understood both in field theory context and in string theory context. Its quantum properties, however, have been more difficult to probe, although the elementary information of the supermultiplet structures is known from a perturbative construction. Recently, a low energy effective theory of monopole

Witold Skiba

Multi-trace scalar operators in the (0,k,0) representations of SU(4)_R share many properties with their single-trace analogs. These multi-trace operators are primary fields of short representations of the N=4 superconformal group. Thus, they have protected dimensions. We show that two- and three-point correlator functions of such operators do not receive rad

S. J. Brodsky

An electron-proton/ion polarized beam collider (EPIC) with high luminosity and center-of-mass energy $\sqrt s = 25$ GeV would be a valuable facility for fundamental studies of proton and nuclear structure and tests of quantum chromodynamics, I review a sample of prospective EPIC topics, particularly semi-exclusive reactions, studies of the proton fragmentati

Thomas G. Rizzo

Many sources of new physics can lead to shifts in the Standard Model predictions for cross sections and asymmetries at the NLC below their direct production thresholds. In this talk we discuss some of the tools that are useful for distinguishing amongst these new physics scenarios. R-parity violation and extensions of the Standard Model gauge structure are t

Miklos Gyulassy, Peter Levai, Ivan Vitev

We investigate the energy loss of quarks and gluons produced in hard processes resulting from final state rescatterings in a finite quark-gluon plasma. The angular distribution of the soft gluon bremsstrahlung induced by n_s=1 rescatterings in the plasma is computed in the Gyulassy-Wang model. Special focus is on how the interference between the initial hard

R. Rapp

We review recent theoretical progress in low-mass dilepton production at CERN-SpS energies. Various hadronic approaches to calculate the vector correlator in hot/dense hadronic matter are discussed and confronted with each other. Possible consequences for the nature of chiral restoration are indicated.

Howard Georgi, Sheldon L. Glashow

Observations of atmospheric neutrinos offer compelling evidence that neutrinos have mass and do oscillate. Preliminary data are compatible with maximal $ν_μ$--$ν_τ$ mixing, but not with pure $ν_μ$--$ν_e$ mixing. In a general three-family scenario with just one relevant squared-mass difference, atmospheric neutrino oscillations involve two mixing angles. The

Andras Ster, Tamas Csorgo, Bengt Lorstad

The final state of Pb + Pb reactions at CERN SPS has been reconstructed with the Buda-Lund hydro model, by performing a simultaneous fit to NA49, NA44 and WA98 data on particle correlations and spectra.

J. Baacke, D. Boyanovsky, H. J. de Vega

The real time non-equilibrium evolution of condensates in field theory requires an initial value problem specifying an initial quantum state or density matrix. Arbitrary specifications of the initial quantum state (pure or mixed) results in initial time singularities which are not removed by the usual renormalization counterterms. We study the initial time s

B. L. Ioffe, A. G. Oganesian

The earlier introduced method of calculation of quark distributions in hadrons, based on QCD sum rules, is improved. The imaginary part of the virtual photon forward scattering amplitude on some hadronic current is considered in the case, when initial and final virtualities of the current $p^2_1$, and $p^2_2$ are different, $p^2_1\not= p^2_2$. The operator p

J. Bijnens, G. Colangelo, G. Ecker

The renormalization of chiral perturbation theory is carried out to next-to-next-to-leading order in the meson sector. We calculate the divergent part of the generating functional of Green functions of quark currents to O(p^6) for chiral SU(n), involving one- and two-loop diagrams. The renormalization group equations for the renormalized low-energy constants

M. A. Braun, C. Pajares

In the colour string model the impact of string percolation on multiplicities, their long-range correlations and average transverse momentum is studied. The multiplicities are shown to be damped by a simple factor which follows from the percolation theory. A clear signature of the phase transition is found to be a behaviour of the correlations for intensive