August 2000 arXiv papers — page 10

E. L. Bratkovskaya, W. Cassing, U. Mosel

We study dilepton production from pp, pd and p Be collisions from 1 - 5 GeV including the $π^0$, $η$, $ω$ and $Δ$ Dalitz decays, direct decays of vector mesons ($ρ$, $ω$) as well as subthreshold $ρ$ production via baryonic resonances (e.g. $D_{13}(1520), P_{11}(1710)$). Our calculations compare rather well with the pp and pd data from the DLS Collaboration,

Andreas Gustavsson

We use holomorphic factorization to find the partition functions of an abelian two-form chiral gauge-field on a flat six-torus. We prove that exactly one of these partition functions is modular invariant. It turns out to be the one that previously has been found in a hamiltonian formulation.

Shin'ichi Nojiri, Sergei D. Odintsov

The attempt to understand if AdS/CFT correspondence may be realized as the one between some AdS-like cosmological space and CFT living on the boundary is made. In order to obtain such cosmology we exchange the time and radial coordinates in d5 Schwarzschild-anti de Sitter (S-AdS) BH (with corresponding signature change). The test on proportionality of free e

P. A. Zizzi

The aim of this paper is to enlight the emerging relevance of Quantum Information Theory in the field of Quantum Gravity. As it was suggested by J. A. Wheeler, information theory must play a relevant role in understanding the foundations of Quantum Mechanics (the "It from bit" proposal). Here we suggest that quantum information must play a relevant r

T. Christodoulakis, G. Kofinas, E. Korfiatis, G. O. Papadopoulos

We investigate the set of spacetime general coordinate transformations (G.C.T.) which leave the line element of a generic Bianchi Type Geometry, quasi-form invariant; i.e. preserve manifest spatial Homogeneity. We find that these G.C.T.'s, induce special time-dependent automorphic changes, on the spatial scale factor matrix $γ_{αβ}(t)$ -along with corres

J. Kolacek, P. Lipavsky, E. H. Brandt

The electric charge density in the vortex lattice of superconductors is studied within the Ginzburg-Landau theory. We show that the electrostatic potential $ϕ$ is proportional to the GL function, $ϕ\propto|ψ|^2-|ψ_\infty|^2$. Numerical results for the triangular vortex lattice are presented.

Dagomir Kaszlikowski

The thesis is divided into three parts. In the first part a new theoretical analysis of interferometric experiments by Alley-Shih, Ou-Mandel and the entanglement swapping experiment is performed. It is shown that the double- and single-photon distinguishability is not necessary for the experiments to be genuine tests against local realism. In the second part

M. Blagojevic, M. Vasilic

We study the conservation laws associated with the asymptotic Poincare symmetry of spacetime in the general teleparallel theory of gravity. Demanding that the canonical Poincare generators have well defined functional derivatives in a properly defined phase space, we obtain the improved form of the generators, containing certain surface terms. These terms ar

N. Kida, M. Tonouchi

Terahertz (THz) radiation with its spectrum extending up to 1 THz has been observed by an illumination of femtosecond optical pulses to optical switching devices fabricated on magnetoresistive manganite thin films; Pr$_{0.7}$Ca$_{0.3}$MnO$_3$. The THz radiation strongly depends on temperature $T$ and its $T$ trend reverses sign across charge-orbital and spin

Hidenori Sonoda

The gauge parameter dependence of QED in the covariant gauge can be determined explicitly by introducing a Stueckelberg field, which is a non-interacting fictitious Goldstone boson field. Examples of QED with electrons or charged scalars are discussed. Our results generalize the long known results on the gauge parameter dependence of the wave function renorm

Jes Madsen

For a limited range of parameters, stable strange quark matter may be negatively charged in bulk due to one gluon exchange interactions. However, the reduction in strange quark occupation in the surface layer, which is responsible for surface tension, more than compensates this for intermediate mass strangelets, which therefore always have positive quark cha

Jochen Weller, Andreas Albrecht

We investigate the potential of a future supernova dataset, as might be obtained by the proposed SNAP satellite, to discriminate among different ``dark energy'' theories that describe an accelerating Universe. We find that many such models can be distinguished with a fit to the effective pressure-to-density ratio, $w$, of this energy. More models can

E. J. Hackett-Jones, D. B. Leinweber, A. W. Thomas

We extrapolate lattice calculations of electric charge radii of the spin-1/2 baryon octet to the physical regime. The extrapolation procedure incorporates chiral perturbation theory and heavy quark effective theory in the appropriate limits. In particular, this procedure includes the non-analytic, logarithmic terms from pion loops. The electric charge radii

V. A. Yurovsky, A. Ben-Reuven

The quasidegeneracy approximation [V. A. Yurovsky, A. Ben-Reuven, P. S. Julienne, and Y. B. Band, J. Phys. B {\bf 32}, 1845 (1999)] is used here to evaluate transition amplitudes for the problem of curve crossing in linear potential grids involving two sets of parallel potentials. The approximation describes phenomena, such as counterintuitive transitions an

N. Mosyagin, A. Titov

Critical remarks in respect to the Generalized Relativistic Effective Core Potential in the recent article of S.A.Wildman at al. are discussed and shown to be incorrect.

Dale L. Schrage

The static and dynamic structural behavior of superconducting cavities for various projects was determined by finite element structural analysis. The b = 0.61 cavity shape for the Neutron Science Project was studied in detail and found to meet all design requirements if fabricated from five millimeter thick material with a single annular stiffener. This 600

Sang-ho Kim, Marc Doleans, Yoon Kang

For many next-generation high intensity proton accelerator applications including the Spallation Neutron Source (SNS), superconducting (SC) RF provides the technology of choice for the linac. In designing the superconducting cavity, several features, such as peak fields, inter-cell coupling, mechanical stiffness, field flatness, external Q, manufacturability

M. J. Fitch, A. C. Melissinos, P. L. Colestock, J. -P. Carneiro

When a relativistic electron bunch traverses a structure, strong electric fields are induced in its wake. We present measurements of the electric field as a function of time as measured at a fixed location in the beam line. For a 12 nC bunch of duration 4.2 ps FWHM, the peak field is measured >0.5 MV/m. Time resolution of ~5 ps is achieved using electro-opti

M. J. Fitch, A. C. Melissinos, N. Barov, J. -P. Carneiro

The A0 Photoinjector at Fermilab can produce high charge (10-14 nC) electron bunches of low emittance (20 pi mm-mrad for 12 nC). We have undertaken a study of the optimal compression conditions. Off-crest acceleration in the 9-cell capture cavity induces an energy-time correlation, which is rotated by the compressor chicane (4 dipoles). The bunch length is m

Dario Villani, Andrei E. Ruckestein

We reconsider the valuation of barrier options by means of binomial trees from a "forward looking" prospective rather than the more conventional "backward induction" one used by standard approaches. This reformulation allows us to write closed-form expressions for the value of European and American put barrier-options on a non-dividend-paying

Scott D. Nelson, Michael Vella

Electron beams of linear induction accelerators experience deflective forces caused by RF fields building up as a result of accelerating cavities of finite size. These forces can significantly effect the beam when a long linac composed of identical cells is assembled. Recent techniques in computational modeling, simulation, and experiments for 20 MeV DARHT-I

M. Castellano, M. Ferrario, F. Tazzioli, L. Catani

Ferroelectric ceramics are tested as photocathodes at INFN Frascati Laboratories. In order to characterize them for use in linac injectors it is important to measure the temporal shape of the emitted current. With a duration of the laser pulse of 25 ps, the required resolution is a few ps. An apparatus has been set up for the purpose, consisting of a 30 kV e

F. Hofmann, C. M. Keil, H. Lenske

The density dependent hadron field (DDRH) theory, previously applied to isospin nuclei and hypernuclei is used to describe $β$-stable matter and neutron stars under consideration of the complete baryon octet. The meson-hyperon vertices are derived from Dirac-Brueckner calculations of nuclear matter and extended to hyperons. We examine properties of density d

Stefan Leupold

We calculate the life time of a resonance in our recently developed framework for a test-particle description of transport processes for states with continuous mass spectra. The result differs from the expression commonly used in transport simulations but agrees with the one derived by Danielewicz and Pratt relating the life time to the scattering phase shif

Yury E. Titarenko, Oleg V. Shvedov, Vyacheslav F. Batyaev, Evgeny I. Karpikhin

The preliminary results are presented of the experimental determination of threshold reaction rates in experimental samples made of Al, Co, Bi, In, Au, to name but a few, placed both inside and on the surface of extended thick W-Na target irradiated with 0.8 GeV protons. The target consists of 26 alternating discs each 150 mm in diameter: 6 tungsten discs ar

Yury E. Titarenko, Oleg V. Shvedov, Yury V. Trebukhovsky, Vyacheslav F. Batyaev

Preliminary results of neutron spectra measurements from Pb, W, and Na targets irradiated by 0.8 and 1.6 GeV protons are presented. Measurements have been carried out using the proton beam extracted from the ITEP synchrotron and the TOF technique. Neutron registration has been carried out using BICRON MAB-511 liquid scintillation counters. Spectra measured a

Yury E. Titarenko, Oleg V. Shvedov, Vyacheslav F. Batyaev, Valery M. Zhivun

The direct gamma-spectrometry method is used to measure more than 350 residual product nuclide yields from 0.1, 0.2, 0.8, and 2.6 GeV proton irradiated HgO targets. The gamma-spectrometer resolution is of 1.8 keV at the 1332 keV gamma-line. The resultant gamma-spectra are processed by the GENIE-2000 code. The gamma-lines are identified, and the cross-section

Yury E. Titarenko, Oleg V. Shvedov, Vyacheslav F. Batyaev, Valery M. Zhivun

113 residual product nuclide yields in a 1.0 GeV proton-irradiated thin monoisotopic 208-Pb sample and 107 residual product nuclide yields in a 2.6 GeV proton-irradiated nat-W sample have been measured and simulated by 8 different codes. The irradiations were made using proton beams extracted from the ITEP synchrotron. The nuclide yields were gamma-spectrome

F. R. Drepper

A new type of nonlinear time series analysis is introduced, based on phases, which are defined as polar angles in spaces spanned by a finite number of delayed coordinates. A canonical choice of the polar axis and a related implicit estimation scheme for the potentially underlying auto-regressive circle map (next phase map) guarantee the invertibility of reco

Henk van Beijeren, Arnulf Latz, J. R. Dorfman

We calculate the spectrum of Lyapunov exponents for a point particle moving in a random array of fixed hard disk or hard sphere scatterers, i.e. the disordered Lorentz gas, in a generic nonequilibrium situation. In a large system which is finite in at least some directions, and with absorbing boundary conditions, the moving particle escapes the system with p

N. P. Landsman

It is well known that rings are the objects of a bicategory, whose arrows are bimodules, composed through the bimodule tensor product. We give an analogous bicategorical description of C*-algebras, von Neumann algebras, Lie groupoids, symplectic groupoids, and Poisson manifolds. The upshot is that known definitions of Morita equivalence for any of these case

Michael Kapovich, John J. Millson, Thomas Treloar

We study the symplectic geometry of the moduli space of closed n-gons with fixed side-lengths in hyperbolic 3-space. We prove that these moduli spaces have a symplectic structure coming from Poisson Lie theory. We construct completely integrable systems on these moduli spaces by bending n-gons along their diagonals. The results of this paper are the analogue

Palle E. T. Jorgensen

In this note we survey results in recent research papers on the use of Lie groups in the study of partial differential equations. The focus will be on parabolic equations, and we will show how the problems at hand have solutions that seem natural in the context of Lie groups. The research is joint with D.W. Robinson, as well as other researchers who are list

Olga Kravchenko

This is an expository note on Fedosov's construction of deformation quantization. Given a symplectic manifold and a connection on it, we show how to calculate the star-product step by step. We draw simple diagrams to solve the recursive equations for the Fedosov connection and for flat sections of the Weyl algebra bundle corresponding to functions. We al

Alexander Polishchuk

We show that elliptic solutions of the classical Yang-Baxter equation can be obtained from triple Massey products on elliptic curve. We introduce the associative version of this equation which has two spectral parameters and construct its elliptic solutions. We also study some degenerations of these solutions.

Gen Yoneda, Takesi Suzuki

In a previous paper (G.Yoneda, Proc.R.Soc.London, A445,(1994),221), we proved the no-interaction theorem for four particles with the assumption that the (linear and angular) momentum on space-like planes is invariant. In this paper, we assume that the momentum on null cones is invariant and prove that there is no interaction for four particles.

Tomas Gomez, Eric R. Sharpe

In this highly speculative note we conjecture that it may be possible to understand features of coincident D-branes, such as the appearance of enhanced non-abelian gauge symmetry, in a purely geometric fashion, using a form of geometry known as scheme theory. We give a very brief introduction to some relevant ideas from scheme theory, and point out how these

T. Heinzl

These lecture notes review the foundations and some applications of light-cone quantization. First I explain how to choose a time in special relativity. Inclusion of Poincare invariance naturally leads to Dirac's forms of relativistic dynamics. Among these, the front form, being the basis for light-cone quantization, is my main focus. I explain a few of

Alon E. Faraggi, Maxim Pospelov

It has been suggested recently that self-interacting dark matter fits better the observational characteristics of galaxy dynamics. We propose that the self-interacting dark matter is composed from the glueballs of the hidden sector non-Abelian gauge group, while the hidden matter states exist in vector-like representation and decouple from the light spectrum

Burton Richter

The purpose of this paper is to provoke a discussion about the right next step in accelerator-based neutrino physics. In the next five years many experiments will be done to determine the neutrino mixing parameters. However, the small parameters $θ_{13}Δm_{21}^2$, and the CP violating phase are unlikely to be well determined. Here, I look at the potential of

Ralf Ricken, Matthias Koll, Dirk Merten, Bernard Ch. Metsch

Within the framework of the instantaneous Bethe-Salpeter equation, we present a detailed analysis of light meson spectra with respect to various parameterizations of confinement in Dirac space. Assuming a linearly rising quark-antiquark potential, we investigate two different spinorial forms (Dirac structures), namely ${1/2}(\Id\otimes\Id - γ^0\otimesγ^0)$ a

G. Vlasov

Relativistic equation of state and velocity comparable with the speed of light are included in consideration of a superfluid rotating in a cylindrical container. Minimizing the free energy, we derive the equation of motion. It admits an analytic solution, the solid-body rotation inside and irrotational motion near the walls of the vessel, providing the vorte

Markus H. Thoma

General arguments as well as different approximations for the in-medium quark propagator in a quark-gluon plasma lead to quark dispersion relations that exhibit a minimum in one branch (plasmino). This minimum causes Van Hove singularities in the dilepton production rate and mesonic correlators, which might have observable consequences.

A. D. Kennedy, Brian Pendleton

We study analytically the computational cost of the Generalised Hybrid Monte Carlo (GHMC) algorithm for free field theory. We calculate the Metropolis acceptance probability for leapfrog and higher-order discretisations of the Molecular Dynamics (MD) equations of motion. We show how to calculate autocorrelation functions of arbitrary polynomial operators, an

Kurt Langfeld

In SU(2) lattice gauge theory, a new self-restricted cooling procedure is developed to uncover the gauge invariant vortex vacuum texture. The emerging vortex vacuum structure amounts to the full string tension and gives rise to a mass dimension four condensate which is of pure vortex origin.

J. William Gary

A summary of some recent studies in jet physics is given. Topics include leading particle production in light flavor events in e+e- annihilations, an analytical treatment of gluon and quark jets at the next-to-next-to-next-to-leading order (3NLO), and various studies performed at LEP and HERA involving separated gluon and quark jets.

Pablo Mora

One possible description of the very early stages of the evolution of the universe is provided by Chaotic Inflationary Cosmology. For that model the role of the inflaton field is played by quantum gravitational effects. We study if such a picture may arise within the framework of Loop Quantum gravity by studying a simple model. While we were unable to reach

Brian Roark, Mark Johnson

This paper examines efficient predictive broad-coverage parsing without dynamic programming. In contrast to bottom-up methods, depth-first top-down parsing produces partial parses that are fully connected trees spanning the entire left context, from which any kind of non-local dependency or partial semantic interpretation can in principle be read. We contras

Joerg Spilker, Martin Klarner, Guenther Goerz

Speech repairs occur often in spontaneous spoken dialogues. The ability to detect and correct those repairs is necessary for any spoken language system. We present a framework to detect and correct speech repairs where all relevant levels of information, i.e., acoustics, lexis, syntax and semantics can be integrated. The basic idea is to reduce the search sp

D. Bolle', D. R. C. Dominguez, S. Amari

The influence of a macroscopic time-dependent threshold on the retrieval process of three-state extremely diluted neural networks is examined. If the threshold is chosen appropriately in function of the noise and the pattern activity of the network, adapting itself in the course of the time evolution, it guarantees an autonomous functioning of the network. I

Viktor Z. Cerovski

Bond-disordered Anderson model in two dimensions on a square lattice is studied numerically near the band center by calculating density of states (DoS), multifractal properties of eigenstates and the localization length. DoS divergence at the band center is studied and compared with Gade's result [Nucl. Phys. B 398, 499 (1993)] and the powerlaw. Although

F. F. Barbosa Filho, J. P. de Lima

The anisotropic XY-model in a transverse field (s=1/2) on the one-dimensional alternating superlattice (closed chain) is considered. The solution of the model is obtained by introducing a generalized Jordan-Wigner transformation which maps the system onto a non-interacting fermion gas. The exact excitation spectrum is determined by reducing the problem to a

S. Lubeck

We consider a stochastic sandpile where the sand-grains of unstable sites are randomly distributed to the nearest neighbors. Increasing the value of the threshold condition the stochastic character of the distribution is lost and a crossover to the scaling behavior of a different sandpile model takes place where the sand-grains are equally transferred to the

Pengcheng Dai, J. A. Fernandez-Baca, N. Wakabayashi, E. W. Plummer

We use neutron scattering to demonstrate the presence of lattice polarons and their short-range correlations for several samples of La$_{1-x}$Ca$_x$MnO$_3$ in the Ca doping range $0.15\leq x\leq 0.3$. We establish the doping dependence of the orientation, commensuration, and coherence length of the polaron correlations and show that the populations of correl

Anton V. Velichko, Adrian Porch, Richard G. Humphreys

Two high-quality Y-Ba-Cu-O thin films on MgO substrates have been investigated using the coplanar resonator technique at 8 and 16 GHz. Both films exhibit an anomalous decrease in their surface impedance, Zs as a function of microwave field, Hrf. In zero dc field, Hrf-dependences of Rs and Xs for both the samples are uncorrelated, and only one of the quantiti

E. Canessa

We make an attempt to map a simple economically motivated model for the price evolution [J. Phys. A: Gen. Math 33, 3637 (2000)] to the phenomenological renormalization group scaling of stock markets. This mapping gives insight into the critical exponents and the renormalization group predictions for the log-periodic oscillations preceding some stock market c

Hans Walliser

Charged skyrmions or spin-textures in the quantum Hall ferromagnet at filling factor nu=1 are reinvestigated using the Hartree-Fock method in the lowest Landau level approximation. It is shown that the single Slater determinant with the minimum energy in the unit charge sector is always of the hedgehog form. It is observed that the magnetization vector's

J. L. Tallon, J. W. Loram, G. V. M. Williams

The recent obervation of a Kondo-like temperature dependence in the Li NMR Knight shift in Ca- and Li- cosubstituted YBa2Cu3O7-d was attributed by Bobroff et al. to be evidence of Li-induced local moments in overdoped Y123. It is shown from Y-NMR measurements on Y0.8Ca0.2Ba2Cu3O7-d and heat capacity studies on Bi2Sr2CaCu2O8 that such a Kondo-like temperature

Philip A. Pinto, Ronald G. Eastman, Tamara Rogers

Currently popular models for Type Ia supernovae (SNe Ia) fall into two general classes. The first comprises explosions of nearly pure carbon/oxygen (C/O) white dwarfs at the Chandrasekhar limit which ignite near their centers. The second consists of lower-mass C/O cores which are ignited by the detonation of an accreted surface helium layer. Explosions of th

S. Stanimirovic

We describe quantitatively the neutral hydrogen (HI) and dust content of the interstellar medium (ISM) in the Small Magellanic Cloud (SMC), using the spatial power spectrum. The velocity modification of the HI density power spectrum is investigated and discussed.

Deborah Haarsma, Joseph Leh'ar, Rennan Barkana

Time-delay measurements of 0957+561 based on radio monitoring now agree with optical monitoring. Recent models incorporate many recent observations, but the systematic uncertainties in the models still dominate the uncertainty in the cosmological results. VLBI observations of the milli-arcsec jet structure have provided the most important set of modeling con

David A. Neufeld

Circumnuclear water masers can respond in two ways to changes in the luminosity of an active galactic nucleus. First, an increase in the X-ray luminosity can lead to an increase in the maser emissivity; and second, an increase in the intrinsic bolometric luminosity may result in a temporary decrease in the difference between the gas and dust temperature and

C. M. Carollo, M. Stiavelli, P. T. de Zeeuw, M. Seigar

We have analysed $V$, $H$ and $J$ HST images for a sample of early- to late-type spiral galaxies, and reported elsewhere the statistical frequency of $R^{1/4}$-law and exponential bulges in our sample as a function of Hubble type, and the frequency of occurrence and structural properties of the resolved central nuclei hosted by intermediate- to late-type bul

D. Nogami, D. Engels, B. T. Gaensicke, E. P. Pavlenko

We report time-resolved photometric observations of the Hamburg Quasar Survey-selected dwarf nova HS 1449+6415 (= RX J1450.5+6403) during the interval from JD 2451672 to 2451724. During a long outburst with a duration of ~12 days, we detected superhumps with a period of 0.0601(5) d, revealing that this star is an SU UMa star. A short outburst which lasted 3

Matthias Tecza, Niranjan Thatte, Frank Eisenhauer, Sabine Mengel

SPIFFI (SPectrometer for Infrared Faint Field Imaging) is the integral field spectrograph of the VLT-instrument SINFONI (SINgle Far Object Near-infrared Investigation). SINFONI is the combination of SPIFFI with the ESO adaptive optics system MACAO (Multiple Application Concept for Adaptive Optics) offering for the first time adaptive optics assisted near inf

M. J. Hardcastle, L. W. Looney

We present 85-GHz observations of the archetypal double-hotspot radio source 3C20 made with the BIMA millimetre array. The resolution of BIMA allows us to separate the two components of the eastern hotspot. By comparing the BIMA observations with existing VLA data, we show that the spectra of the two hotspot components are very similar, despite the clear dif

Kartik Sheth, Stuart N. Vogel, Christine D. Wilson, T. M. Dame

We present new observations of a 2' field in the north-eastern spiral arm of M31. In the 0.8 x 3.6 kpc mosaicked region, we have detected six distinct, large complexes of molecular gas, most of which lie along the spiral arm dust lane or in the vicinity of HII regions. The mean properties of these complexes are as follows: diameter ~ 57+/-13 pc, fwhm vel

Wei-Min Gu, Ju-Fu Lu

We show that, unlike the results presented previously in the literature, the transition from an outer Shakura-Sunyaev disk (SSD) to an advection-dominated accretion flow (ADAF) is possible for large values of the viscosity parameter $α>0.5$. The transition is triggered by thermal instability of a radiation-pressure-supported SSD. The transition radius is clo

A. Alonso-Herrero, C. W. Engelbracht, M. J. Rieke, G. H. Rieke

The modest extinction and reasonably face-on viewing geometry make the luminous IR galaxy NGC1614 an ideal laboratory for study of a powerful starburst. HST/NICMOS observations show: 1.) deep CO stellar absorption, tracing a starburst nucleus about 45 pc in diameter; 2.) surrounded by a ~600 pc diameter ring of supergiant HII regions revealed in Pa$α$ line e

L. Decin, C. Waelkens, K. Eriksson, B. Gustafsson

A detailed spectroscopic study of the ISO-SWS data of the red giant Alpha Tau is presented, which enables not only the accurate determination of the stellar parameters of Alpha Tau, but also serves as a critical review of the ISO-SWS calibration. This study is situated in a broader context of an iterative process in which both accurate observations of stella

Graham P. Smith, Jean-Paul Kneib, Harald Ebeling, Oliver Czoske

We analyse the mass distribution in the core of A383 (z=0.188), one of 12 X-ray luminous clusters at z~0.2 selected for a comprehensive and unbiased study of the mass distribution in massive clusters. Deep HST imaging reveals a wide variety of gravitationally lensed features in A383, including a giant arc formed from the strongly-lensed images of 2 backgroun

Adan Cabello

A proof of Bell's theorem using two maximally entangled states of two qubits is presented. It exhibits a similar logical structure to Hardy's argument of ``nonlocality without inequalities''. However, it works for 100% of the runs of a certain experiment. Therefore, it can also be viewed as a Greenberger-Horne-Zeilinger-like proof involving o

R. M. Jones, N. M. Kroll, R. H. Miller, T. O. Raubenheimer

In the NLC (Next Linear Collider) small misalignments in each of the individual accelerator structures (or the accelerator cells) will give rise to wakefields which kick the beam from its electrical axis. This wakefield can cause BBU (Beam Break Up) or at the very least it will dilute the emittance of the beam. Several Gaussian detuned structures have been d

Shigeki Matsutani

Closed loop solitons in a plane, whose curvatures obey the modified Korteweg-de Vries equation, were investigated. It was shown that their tangential vectors are expressed by ratio of Weierstrass sigma functions for genus one case and ratio of Baker's sigma functions for the genus two case. This study is closely related to classical and quantized elastic

Andreea S. Font, George F. Mitchell, Goeran Sandell

New molecular (13CO J=3-2) and dust continuum (450 and 850 micron) SCUBA maps of the NGC7129 star forming region are presented, complemented by C18O J=3-2 spectra at several positions within the mapped region. The maps include the Herbig Ae/Be star LkHalpha 234, the far-infrared source NGC 7129 FIRS2 and several other pre-stellar sources embedded within the

R. Klippert, H. C. Rosu

The strictly nonrelativistic isospectral scheme based on the general Riccati solution and Darboux transformation function corresponding to excited states is presented on the following examples: the harmonic oscillator, the square well, and the hydrogen atom

R. M. Jones, T. Higo, Y. Higashi, N. Toge

In fabricating the first X-Band RDDS (Rounded Damped Detuned Structure) accelerator structure, microwave measurements are made on short groups of discs prior to bonding the discs of the entire structure. The design dispersion curves are compared with the frequency measurements. The theory utilised is based on a circuit model adapted to a short stack of slowl

N. M. Kroll, C. -K. Ng, D. C. Vier

We present numerical procedures for analyzing the properties of periodic structures and associated couplers based upon time domain simulation. Simple post processing procedures are given for determining Brillouin diagrams and complex field distributions of the traveling wave solutions, and the reflection coefficient of the traveling waves by the input and ou

Antonina N. Fedorova, Michael G. Zeitlin

We present the applications of variational-wavelet approach for computing multiresolution/multiscale representation for solution of some approximations of Vlasov-Maxwell-Poisson equations.

N. Ouchi, E. Chishiro, C. Tsukishima, K. Mukugi

The superconducting (SC) proton linac is proposed in the JAERI/KEK Joint Project for a high-intensity proton accelerator in the energy region from 400 to 600 MeV. Highly stable fields in the SC cavities are required under the dynamic Lorentz force detuning. A new model describing the dynamic Lorentz detuning has been developed and the validity has been confi

R. M. Jones, R. H. Miller, T. O. Raubenheimer, G. V. Stupakov

The main linacs of the Next Linear Collider (NLC) will contain several thousand X-band RDDS (Rounded Damped Detuned Structures). The transverse wakefield in the structures is reduced by detuning the modal frequencies such that they destructively interfere and by four damping manifolds per structure which provide weak damping. Errors in the fabrication of the

C. Adolphsen, W. Baumgartner, K. Jobe, R. Loewen

During the initial phase of operation, the linacs of the Next Linear Collider (NLC) will contain roughly 5000 X-Band accelerator structures that will accelerate beams of electrons and positrons to 250 GeV. These structures will nominally operate at an unloaded gradient of 72 MV/m. As part of the NLC R&D program, several prototype structures have been built a

Ji Qiang, Salman Habib

Langevin simulation provides an effective way to study collisional effects in beams by reducing the six-dimensional Fokker-Planck equation to a group of stochastic ordinary differential equations. These resulting equations usually have multiplicative noise since the diffusion coefficients in these equations are functions of position and time. Conventional al

Andrei Seryi

Investigations of slow transverse motion of the linac tunnel of the Stanford Linear Collider have been performed over period of about one month in December 1999 -- January 2000. The linac laser alignment system, equipped with a quadrant photodetector, allowed submicron resolution measurement of the motion of the middle of the linac tunnel with respect to its

M. D. Woodley, P. E. Emma

In future linear colliders the luminosity will depend on maintaining the small emittance aspect ratio delivered by damping rings. Correction of cross-plane coupling can be important in preventing dilution of the beam emittance. In order to minimize the vertical emittance, especially for a flat beam, it is necessary to remove all cross-plane (x-y) correlation

R. Li

Recent measurements of the coherent synchrotron radiation (CSR) effects indicated that the observed beam emittance growth and energy modulation are often bigger than previous predictions based on Gaussian longitudinal charge distributions. In this paper, by performing a model study, we show both analytically and numerically that when the longitudinal bunch c

Valery A. Dolgashev, Sami G. Tantawi

An efficient method for frequency domain analysis of 2D cross-field devices is presented. This work was done to analyze and design high efficiency magnetrons. Arbitrary device-geometries are described by a piecewise planar boundary. The method is based on an expansion of the electromagnetic fields into a set of cavity eigenmodes. In order to obtain the self-

O. L. Savchenko, A. I. Steshenko

A role of different components in the wave function of the weakly bound light nuclei states was studied within the framework of the cluster model, taking into account of orbitals "polarization". It was shown that a limited number of structures associated with the different modes of nucleon motion can be of great importance for such systems. Examples

Elliott H. Lieb, Jakob Yngvason

According to a formula that was put forward many decades ago the ground state energy per particle of an interacting, dilute Bose gas at density $ρ$ is $2π\hbar^2ρa/m$ to leading order in $ρa^3\ll 1$, where $a$ is the scattering length of the interaction potential and $m$ the particle mass. This result, which is important for the theoretical description of cu

Yasuharu Honda, Masaki Yasue

In supersymmetric quantum chromodynamics with N_c-colors and N_f-flavors of quarks, our effective superpotential provides the alternative description to the Seiberg's N=1 duality at least for N_f>=N_c+2, where spontaneous breakdown of chiral symmetries leads to SU(N_c)_{L+R}xSU(N_f-N_c)_LXSU(N_f-N_c)_R as a nonabelian chiral symmetry. The anomaly-matchin

David H. Adams, Emil M. Prodanov

The standard evaluation of the partition function $Z$ of Schwarz's topological field theory results in the Ray--Singer analytic torsion. Here we present an alternative evaluation which results in Z=1. Mathematically, this amounts to a novel perspective on analytic torsion: it can be formally written as a ratio of volumes of spaces of differential forms w

S. F. Hassan, R. Minasian

Non-trivial configurations of Yang-Mills fields and gravitational backgrounds induce charges on Dp-branes that couple them to lower and higher RR potentials. We show that these couplings can be described in a systematic and coordinate independent way by using Clifford multiplication. In the minimal formulation, D-brane charges and RR potentials combine into

C. A. Ramm

Structures in invariant mass distributions from (mu,pi) combinations in the range 0.380<mupi<0.470 GeV from neutrino and kaon experiments are presented in comparable formats. No artifacts have been found to account for any part of the structure. Hypotheses that the similarities are due to recurrent statistical fluctuations are beyond credibility. My conclusi

E. Cuansing, H. Nakanishi

We study, on a square lattice, an extension to fully coordinated percolation which we call iterated fully coordinated percolation. In fully coordinated percolation, sites become occupied if all four of its nearest neighbors are also occupied. Repeating this site selection process again yields the iterated fully coordinated percolation model. Our results show

Azadeh Samadani, A. Kudrolli

We report the effect of interstitial fluid on the extent of segregation by imaging the pile that results after bidisperse color-coded particles are poured into a silo. Segregation is sharply reduced and preferential clumping of small particles is observed when a small volume fraction of fluid $V_f$ is added. We find that viscous forces in addition to capilla

Martin Weigel, Wolfhard Janke

Conformal field theory predicts finite-size scaling amplitudes of correlation lengths universally related to critical exponents on sphere-like, semi-finite systems $S^{d-1}\times\mathbb{R}$ of arbitrary dimensionality $d$. Numerical studies have up to now been unable to validate this result due to the intricacies of lattice discretisation of such curved spac

Ronald Drimmel, David Spergel

Using far-infrared 240 micron and near-infrared K band data from the COBE/DIRBE instrument, we model the Galactic stellar and dust distribution. Making the assumption that the Galaxy is transparent in the 240 micron band, the dust emission is modeled using the following components: a warped exponential disk of scale length 0.26 R_sun, a spiral arm component

Yasuhiro Shioya, Yoshiaki Taniguchi, Neil Trentham

We investigate the photometric properties of six super stellar clusters (SSCs) seen in both the optical and near-infrared Hubble Space Telescope images of the local ultraluminous starburst galaxy Arp 220. Three of the SSCs are located in the central 0.5 kpc region. The remaining three are in the circumnuclear region between 0.5 kpc and 2.5 kpc from the centr

David Merritt, Laura Ferrarese

We investigate the differences in the M(BH)-sigma relation derived recently by Ferrarese & Merritt (2000) and Gebhardt et al. (2000). The shallower slope found by the latter authors (3.75 vs. 4.8) is due partly to the use of a regression algorithm that ignores measurement errors, and partly to the value of the velocity dispersion adopted for a single galaxy,

Motoyuki Saijo, Takashi Nakamura

We computed the spectrum of gravitational waves from a dust disk star of radius R inspiraling into a Kerr black hole of mass M and specific angular momentum a. We found that when R is much larger than the wave length of the quasinormal mode, the spectrum has several peaks and the separation of peaks $Δω$ is proportional to $R^{-1}$ irrespective of M and a. T