May 2000 arXiv papers — page 15

F. X. Timmes, J. C. Niemeyer

The burning regimes encountered by laminar deflagrations and ZND detonations propagating through helium-rich compositions in the presence of buoyancy-driven turbulence are analyzed. Particular attention is given to models of X-ray bursts which start with a thermonuclear runaway on the surface of a neutron star, and the thin shell helium instability of interm

L. Kuiper, W. Hermsen, F. Verbunt, D. J. Thompson

We report circumstantial evidence for the first detection of pulsed high-energy gamma-ray emission from a millisecond pulsar, PSR J0218+4232, using data collected with the Energetic Gamma Ray Experiment (EGRET) on board the Compton Gamma Ray Observatory (CGRO). The EGRET source 3EG J0222+4253 is shown to be spatially consistent with PSR J0218+4232 for the en

F. Verbunt, M. H. van Kerkwijk, J. J. M. in 't Zand, J. Heise

The BeppoSAX Wide Field Cameras detected a transient in NGC6440 on 1998 Aug 22. ROSAT did not detect this source on 1998 Sep 8, indicating that the X-ray flux had decreased by a factor 400 at least, and/or that the X-ray spectrum had become appreciably softer. Analysis of archival ROSAT HRI data reveals two sources associated with NGC6440; one of these may b

Avinash A. Deshpande

During the past decade or so, measurements of Galactic HI absorption using VLBI against extra-galactic sources, as well as multi-epoch observatios in pulsar directions, have detected small-scale transverse variations corresponding to tens of AU at the distance of the absorbing matter. Hitherto these measurements have been interpreted as small-scale structure

W. Pietsch, A. Vogler, U. Klein, H. Zinnecker

Spatial and spectral analysis of deep ROSAT HRI and PSPC observations of the near edge-on starburst galaxy NGC 253 reveal diffuse soft X-ray emission, which contributes 80% to its total X-ray luminosity (L$_{\rm X} = 5 10^{39}$ \ergsec, corrected for foreground absorption). The nuclear area, disk, and halo contribution to the luminosity is about equal. The s

Stefano Sello

Using wavelet analysis approach, we can derive a measure of the disorder content of solar activity, following the temporal evolution of the so-called wavelet entropy. The interesting feature of this parameter is its ability to extract a dynamical complexity information, in terms of frequency distribution of the energy content, avoiding restrictions, common i

M. R. Bate, I. A. Bonnell, C. J. Clarke, S. H. Lubow

We consider the dynamics of a protostellar disc in a binary system where the disc is misaligned with the orbital plane of the binary, with the aim of determining the observational consequences for such systems. The disc wobbles with a period approximately equal to half the binary's orbital period and precesses on a longer timescale. We determine the char

D. Santos, F. Mayet, Yu. M. Bunkov, A. Drezet

MACHe3 (MAtrix of Cells of superfluid He3) is a project of a new detector for direct Dark Matter (DM) search. A cell of superfluid He3 has been developed and the idea of using a large number of such cells in a high granularity detector is proposed.This contribution presents, after a brief description of the superfluid He3 cell, the simulation of the response

Keiichi Wada, Marco Spaans, Sungeun Kim

Based on our high resolution, two-dimensional hydrodynamical simulations, we propose that large cavities may be formed by the nonlinear development of the combined thermal and gravitational instabilities, without need for stellar energy injection in a galaxy modeling the Large Magellanic Clouds (LMC). Our numerical model of the star formation allows us to fo

M. J. I. Brown, R. L. Webster, B. J. Boyle

We present measurements of the angular correlation function of galaxies selected from a B_J=23.5 multicolour survey of two 5 degree by 5 degree fields located at high galactic latitudes. The galaxy catalogue of approximately 400,000 galaxies is comparable in size to catalogues used to determine the galaxy correlation function at low-redshift. Measurements of

Julianne J. Dalcanton, Rebecca A. Bernstein

We present optical (B & R) and infrared (K_s) images and photometry for a sample of 49 extremely late-type, edge-on disk galaxies selected from the Flat Galaxy Catalog of Karenchentsev et al. (1993). Our sample was selected to include galaxies with particularly large axial ratios, increading the likelihood that the galaxies in the sample are truly edge-on. W

V. M. Kaspi, J. R. Lackey, D. Chakrabarty

We report the detection of a sudden spin-up of the 11 s anomalous X-ray pulsar 1RXS J170849.0-4000910 in regular timing observations made with the Rossi X-ray Timing Explorer. The event, which occurred between MJD 51446 (1999 September 25) and 51472 (1999 October 21), is well characterized by an increase in the rotational frequency of magnitude (Delta nu / n

James S. Bullock, Avishai Dekel, Joel R. Primack, Rachel S. Somerville

We present a method for constraining the evolution of the galaxy luminosity-velocity (LV) relation in hierarchical scenarios of structure formation. The comoving number density of dark-matter halos with circular velocity of 200 km/s is predicted in favored CDM cosmologies to be nearly constant over the redshift range 0<z<5. Any observed evolution in the dens

Yair Sigad, Tsafrir S. Kolatt, James S. Bullock, Andrey V. Kravtsov

We study the distribution functions of mass and circular velocity for dark matter halos in N-body simulations of the $Λ$CDM cosmology, addressing redshift and environmental dependence. The dynamical range enables us to resolve subhalos and distinguish them from &#34;distinct&#34; halos. The mass function is compared to analytic models, and is used to derive

Valerio Bozza

We investigate the caustic structure of a lens composed by a discrete number of point-masses, having mutual distances smaller than the Einstein radius of the total mass of the system. Along with the main critical curve, it is known that the lens map is characterized by secondary critical curves producing small caustics far from the lens system. By exploiting

Xavier Waintal, Edward B. Myers, Piet W. Brouwer, D. C. Ralph

We present a calculation of current-induced torques in metallic magnetic multilayers derived from the spin-dependent transmission and reflection properties of the magnetic layers. A scattering formalism is employed to calculate the torques in a magnetic-nonmagnetic-magnetic trilayer, for currents perpendicular to the layers, in both the ballistic and diffusi

Panagiota Kanti, Keith A. Olive, Maxim Pospelov

We analyze cosmological solutions in the class of two-brane models with arbitrary tensions which contain matter with general equations of state. We show that the mass hierarchy between the two branes is determined by the ratio of the lapse functions evaluated on the branes. This ratio can be sufficiently small without fine-tuning the brane separation, once t

Clarissa-Marie Claudel, K. S. Virbhadra, G. F. R. Ellis

The photon sphere concept in Schwarzschild space-time is generalized to a definition of a photon surface in an arbitrary space-time. A photon sphere is then defined as an SO(3)xR-invariant photon surface in a static spherically symmetric space-time. It is proved, subject to an energy condition, that a black hole in any such space-time must be surrounded by a

D. M. Appleby

It is shown that the models recently proposed by Meyer, Kent and Clifton (MKC) exhibit a novel kind of contextuality, which we term existential contextuality. In this phenomenon it is not simply the pre-existing value but the actual existence of an observable which is context dependent. This result confirms the point made elsewhere, that the MKC models do no

M. Cvetic, H. Lu, C. N. Pope, A. Sadrzadeh

We construct a consistent reduction of type IIA supergravity on S^3, leading to a maximal gauged supergravity in seven dimensions with the full set of massless SO(4) Yang-Mills fields. We do this by starting with the known S^4 reduction of eleven-dimensional supergravity, and showing that it is possible to take a singular limit of the resulting standard SO(5

Susana J. Landau, Hector Vucetich

We consider astronomical and local bounds on time variation of fundamental constants to test some generic Kaluza-Klein-like models and some particular cases of Beckenstein theory. Bounds on the free parameters of the different theories are obtained. Furthermore, we find that none of the proposed models, is able to explain recent results [Webb99,Webb00] claim

L. Brink, R. R. Metsaev, M. A. Vasiliev

Massless fields of generic Young symmetry type in $AdS_d$ space are analyzed. It is demonstrated that in contrast to massless fields in Minkowski space whose physical degrees of freedom transform in irreps of $o(d-2)$ algebra, $AdS$ massless mixed symmetry fields reduce to a number of irreps of $o(d-2)$ algebra. From the field theory perspective this means t

E895 Collaboration, H. Liu, N. N. Ajitanand, J. Alexander

Using the large acceptance Time Projection Chamber of experiment E895 at Brookhaven, measurements of collective sideward flow in Au + Au collisions at beam energies of 2, 4, 6 and 8A GeV are presented in the form of in-plane transverse momentum <Px> and the first Fourier coefficient of azimuthal anisotropy v_1. These measurements indicate a smooth variation

Carl E. Carlson, Christopher D. Carone

We consider the strong decays of the lowest-lying radially excited baryons, in SU(6) language the states comprising the first excited 56-plet. Assuming a single-quark decay approximation, and negligible configuration mixing, we make model-independent predictions for the partial decay widths to final states with a single meson. Masses of unobserved states are

Steffen Bass, Pawel Danielewicz, Scott Pratt

A novel state of matter has been hypothesized to exist during the early stage of relativistic heavy ion collisions, with normal hadrons not appearing until several fm/c after the start of the reaction. To test this hypothesis, correlations between charges and their associated anticharges are evaluated with the use of balance functions. It is shown that late-

P. Levy, F. Parisi, G. Polla, D. Vega

A systematic study of phase separation effects in polycrystalline La_0.5 Ca_0.5 Mn O_3 obtained under different thermal treatments is reported. Samples with average grain size ranging from 200 to 1300 nm were studied. Magnetic and electrical measurements show quantitative differences among samples in their low temperature behavior. indicating that the fracti

Bert Schroer

Using the previously gained insight about the particle/field relation in conformal quantum field theories which required interactions to be related to the existence of particle-like states associated with fields of anomalous scaling dimensions, we set out to construct a classification theory for the spectra of anomalous dimensions. Starting from the old obse

H. Leeb, H. Groetz, J. Kasper, R. Lipperheide

An experimental method is proposed which allows the complete determination of the complex reflection coefficient for absorptive media for positive and negative values of the momenta. It makes use of magnetic reference layers and is a modification of a recently proposed technique for phase determination based on polarization measurements. The complex reflecti

S. Raj, H. C. Padhi, P. Rayachaudhury, A. K. Nigam

Relative $K$ x-ray intensities of $Mn$ in $Mn$, $MnO_{2}$, $LaMnO_{3}$ and $La_{0.7}B_{0.3}MnO_{3}$ ($B$ = $Ca$, $Sr$, and $Ce$) systems have been measured following excitation by 59.54 keV $γ$-rays from a 200 mCi $^{241}$Am point-source. The measured results for the compounds deviate significantly from the results of pure $Mn$. Comparison of the experimenta

Masanao Ozawa

Quantum mechanics predicts the joint probability distributions of the outcomes of simultaneous measurements of commuting observables, but the current formulation lacks the operational definition of simultaneous measurements. In order to provide foundations of joint statistics of local general measurements on entangled systems in a general theoretical framewo

Abel Camacho

In this work we introduce two experimental proposals that could shed some light upon the inertial properties of intrinsic spin. In particular we will analyze the role that the gravitomagnetic field of the Earth could have on a quantum system with spin 1/2. We will deduce the expression for Rabi transitions, which depend, explicitly, on the coupling between t

M. Kachelriess, M. Plumacher

It has been suggested that ultrahigh energy neutrinos can acquire cross-sections approaching hadronic size if the string scale is as low as 1-10 TeV. In this case, the vertical air showers observed with energies above the Greisen-Zatsepin-Kuzmin cutoff at E approximately 6x10^{19} eV could be initiated by neutrinos which are the only known primaries able to

K. G. Chetyrkin, R. V. Harlander, J. H. Kuehn

The total cross section for the production of massive quarks in electron positron annihilation can be predicted in perturbative QCD. After expansion in m^2/s the quartic terms, i.e. those proportional to m^4/s^2, are calculated up to order \alpha_s^3 for vector and axial current induced rates. Predictions relevant for charm, bottom and top quarks production

Y. Brihaye

Two families of quasi exactly solvable 2*2 matrix Schroedinger operators are constructed. The first one is based on a polynomial matrix potential and depends on three parameters. The second is a one-parameter generalisation of the scalar Lame equation. The relationship between these operators and QES Hamiltonians already considered in the literature is point

V. Yu. Ponomarev, P. F. Bortignon, R. A. Broglia, V. V. Voronov

A systematic microscopic study of the anharmonic properties of the double giant dipole resonance (DGDR) has been carried out, for the first time, for nuclei with mass number $A$ spanning the whole mass table. It is concluded that the corrections of the energy centroid of the $J^π = 0^+$ and $2^+$ components of the DGDR from its harmonic limit are negative, h

Yu. Kagan, A. E. Muryshev

The strong spin-dipole relaxation, accompanying BEC in a gas of atomic hydrogen, determines the formation of a quasistationary state with a flux of particles in energy space to the condensate. This state is characterized by a significant enhancement of the low-energy distribution of non-condensate particles resulting in a growth of their spatial density in t

S. Ansoldi, C. Castro, E. Spallucci

We consider an action for a closed, bosonic, p-brane, where the brane tension is not an assigned parameter but rather it is induced by a maximal rank gauge p-form. This model is classically equivalent to the Nambu--Goto/Howe-Tucker model. We investigate how this classical equivalence can be implemented in the path integral framework. For this purpose we adop

Andrea Gregori

We study the bulk effective theory of a class of orbifolds of the type IIB string with D5-branes, compactified to four dimensions. These constructions are connected, in a region of their moduli space, to some orbifolds of the type I and heterotic string. We compare the effective actions through the coupling of the R^2 term, and we argue that these orbifolds

T. Asaka, K. Hamaguchi, Koshiro Suzuki

We investigate the cosmological gravitino problem in gauge-mediated supersymmetry breaking models, where the gravitino becomes in general the lightest supersymmetric particle (LSP). In order to avoid the overclosure of the stable gravitino, the reheating temperature of inflation $T_R$ should be low enough. Furthermore, if the gravitino mass is larger than ab

A. Sibirtsev, K. Tsushima, A. W. Thomas

$J/\Psi$ dissociation in collisions with nucleons is studied within a boson exchange model and the energy dependence of the dissociation cross section is calculated from the threshold for $\Lambda_c{\bar D}$ production to high energies. We illustrate the agreement of our results with calculations based on short distance QCD and Regge theory. The compatibilit

Heon-Young Chang, Insu Yi

We study the statistics of gamma-ray bursts, assuming that gamma-ray bursts are cosmological and they are beamed in the form of a conical jet with a large bulk Lorentz factor $\sim 100$. In such a conic beam, the relativistic ejecta may have a spatial variation in the bulk Lorentz factor and the density distribution of gamma-ray emitting jet material. An app

Mayumi Aoki, Eri Asakawa, Makiko Nagashima, Noriyuki Oshimo

We study the decay B\to X_sγin a minimal extension of the standard model with extra up- and down-type quarks whose left- and right-handed components are both SU(2) singlets. Constraints on the extended Cabibbo-Kobayashi-Maskawa matrix are obtained from the experimental results for the branching ratio. Even if the extra quarks are too heavy to be detected in

Yoshio Uwano

The Bertrand-Darboux integrability condition for a certain class of perturbed harmonic oscillators is studied from the viewpoint of the Birkhoff-Gustavson(BG)-normalization: By solving an inverse problem of the BG-normalization on computer algebra, it is shown that if the perturbed harmonic oscillators with a homogeneous-{\it cubic} polynomial potential and

Houri Ziaeepour

Recent theoretical and observational motivations for existence of a decaying Ultra Heavy Dark Matter (UHDM) are reviewed. We show that present data from Ultra High Energy Cosmic Rays (UHECRs) and SN - Ia are compatible with a relatively short lifetime of UHDM.

Gilles Brassard, Peter Hoyer, Michele Mosca, Alain Tapp

Consider a Boolean function $χ: X \to \{0,1\}$ that partitions set $X$ between its good and bad elements, where $x$ is good if $χ(x)=1$ and bad otherwise. Consider also a quantum algorithm $\mathcal A$ such that $A |0\rangle= \sum_{x\in X} α_x |x\rangle$ is a quantum superposition of the elements of $X$, and let $a$ denote the probability that a good element

S. X. Hu, C. H. Keitel

We numerically investigate the dynamics of multiply charged hydrogenic ions in near-optical linearly polarized laser fields with intensities of order 10^16 to 10^17 W/cm^2. Depending on the charge state Z of the ion the relation of strength between laser field and ionic core changes. We find around Z=12 typical multiphoton dynamics and for Z=3 tunneling beha

L. Polley

The quantum state of a particle can be completely specified by a position at one instant of time. This implies a lack of information, hence a symmetry, as to where the particle will move. We here study the consequences for free particles of spin 0 and spin 1/2. On a cubic spatial lattice a hopping equation is derived, and the continuum limit taken. Spin 0 le

A. L. Perez Prieto, S. Brouard, J. G. Muga

Due to a transient quantum interference during a wavepacket collision with a potential barrier, a particular momentum, that depends on the potential parameters but is close to the initial average momentum, becomes suppressed. The hole left pushes the momentum distribution outwards leading to a significant constructive enhancement of lower and higher momenta.

T. Ya. Popova, A. K. Popov

An analysis is made of the effect of a strong field on the shape of the amplification spectral line for mono-velocity V-type three-level atoms. There are three strong-field contributions, differing in their dependence on the set of relaxation parameters of the medium and on the differences among the populations corresponding to the Raman transitions. An anal

T. Ya. Popova, A. K. Popov

Optimal conditions to acomplish amplification without inversion in three-level schemes based on quantum nonlinear interference effects are analyzed. Specific features of relaxation processes in optical transitions seting these conditions apart from those in microwave schemes are outlined. Numerical evaluations related to neon 2s_2-2p_4-3s_2 transitions are g

Raoul Nakhmanson

A simple analogy to understand the quantum-mechanical entanglement within local-realistic world is presented.

Adonai S. Sant&#39;Anna, Clovis A. S. Maia

We present an axiomatic framework for what we call Mach&#39;s mechanics, inspired on the ideas by A. K. T. Assis and P. Graneau about relational mechanics. We show that contrarily to what is suggested by these authors, Mach&#39;s principle does not need to be committed with any Weber&#39;s like gravitational force. Actually it is possible to settle an axioma

D. Mathur

Benzene, with its sea of delocalized $π$-electrons in the valence orbitals, is identified as an example of a class of molecules that enable establishment of the correspondence between intense ion-induced and laser-light-induced fields in experiments that probe ionization dynamics in temporal regimes spanning the attosecond and picosecond ranges.

B. Roy, Mala Das, S. C. Roy, B. K. Chatterjee

It has been reported so far that superheated drop detector made of R-12 at room temperature are sensitive to neutrons yet insensitive to photons. This property makes its use as one of the most useful neutron dosimeter. The photon sensitivity of R12 at room temperature when exposed to 59.54kev photons obtained from radioactive Am has been noted for the first

V. A. Dzuba, V. V. Flambaum

We have performed relativistic many-body calculations of the hyperfine interaction in the $6s$ and $7s$ states of Cs, including the off-diagonal matrix element. The calculations were used to determine the accuracy of the semi-empirical formula for the electromagnetic transition amplitude $<6s|M1|7s>$ induced by the hyperfine interaction. We have found that e

Michael W. N. Ibrahim

We discuss the variety of coordinates often used to characterize the coherent state classical limit of an algebraic model. We show selection of appropriate coordinates naturally motivates a procedure to generate a single particle Schrödinger hamiltonian which, for low energy states, gives equivalent results to a bosonic algebraic model to leading order in $N

Michael W. N. Ibrahim

We use recent results regarding the geometry of the U(3) bosonic algebraic model to motivate a hybrid algebraic-Schrödinger approach to the 2D Franck-Condon problem analogous to 1D approaches. This approach allows one to analyze bent to linear Franck-Condon transitions of triatomic molecules as well as clarifies the angular momentum dependance of the Franck-

J. A. Sheikh, R. Wyss

The subtle interplay between the two nuclear superfluids, isovector T=1 and isoscalar T=0 phases, are investigated in an exactly soluble model. It is shown that T=1 and T=0 pair-modes decouple in the exact calculations with the T=1 pair-energy being independent of the T=0 pair-strength and vice-versa. In the rotating-field, the isoscalar correlations remain

T. Duguet, P. Bonche, P. -H. Heenen

Rotational bands of $^{252, 253, 254}$No and the fission barriers of $^{254}$No at spin 0$\hbar$ and 20$\hbar$ are calculated with the Hartree-Fock-Bogolyubov theory and the Lipkin-Nogami approximate particle number projection. The SLy4 Skyrme force is used in the particle-hole channel. A zero-range force with and without density-dependence is used in the pa

K. Saito

We study the binding energy differences of the valence proton and neutron of the mirror nuclei, $^{15}$O - $^{15}$N, $^{17}$F - $^{17}$O, $^{39}$Ca - $^{39}$K and $^{41}$Sc - $^{41}$Ca, using the quark-meson coupling model. The calculation involves nuclear structure and shell effects explicitly. It is shown that binding energy differences of a few hundred ke

K. Saito

Using the quark-meson coupling model, we study the longitudinal response function for quasielastic electron scattering from nuclear matter within relativistic RPA. In QMC the coupling constant between the scalar meson and the nucleon is expected to decrease with increasing nuclear density. Furthermore, since the electromagnetic form factors of the in-medium

A. Wagner, C. Muentz, H. Oeschler, C. Sturm

The emission pattern of charged pions has been measured in Au+Au collisions at 1 GeV/nucleon incident energy. In peripheral collisions and at target rapidities, high-energy pions are emitted preferentially towards the target spectator matter. In contrast, low-energy pions are emitted predominantly in the opposite direction. The corresponding azimuthal anisot

Krzysztof Sacha

The dynamics of atomic hydrogen placed in a static electric field and illuminated by elliptically polarized microwaves is studied in the range of small field amplitudes where perturbation calculations are applicable. For a general configuration of the fields any generalized time-reversal symmetry is broken and, as the classical dynamics is chaotic, the level

Andrey A. Sukhorukov, Yuri S. Kivshar, Ole Bang, Costas M. Soukoulis

We analyze two-color spatially localized modes formed by parametrically coupled fundamental and second-harmonic fields excited at quadratic (or chi-2) nonlinear interfaces embedded into a linear layered structure --- a quasi-one-dimensional quadratic nonlinear photonic crystal. For a periodic lattice of nonlinear interfaces, we derive an effective discrete m

Vadim Kostrykin, Robert Schrader

In this article we prove an upper bound for the Lyapunov exponent $γ(E)$ and a two-sided bound for the integrated density of states $N(E)$ at an arbitrary energy $E>0$ of random Schrödinger operators in one dimension. These Schrödinger operators are given by potentials of identical shape centered at every lattice site but with non-overlapping supports and wi

M. A. Jafarizadeh, S. J. Akhtarshenas

By introducing the generalized master function of order up to four together with corresponding weight function, we have obtained all quasi-exactly solvable second order differential equations. It is shown that these differntial equations have solutions of polynomial type with factorziation properties, that is polynomial solutions Pm(E) can be factorized in t

U. Haagerup, H. P. Rosenthal, F. A. Sukochev

Let N and M be von Neumann algebras. It is proved that L^p(N) does not Banach embed in L^p(M) for N infinite, M finite, 1 < or = p < 2. The following considerably stronger result is obtained (which implies this, since the Schatten p-class C_p embeds in L^p(N) for N infinite). Theorem: Let 1 < or = p < 2 and let X be a Banach space with a spanning set (x_{ij}

B. Weisfeiler

This paper contains a complete proof of a fundamental theorem on the normalizers of unipotent subgroups in semisimple algebraic groups.

Anastasia Ruzmaikina

We give a new estimate on Stieltjes integrals of Hölder continuous functions and use it to prove an existence-uniqueness theorem for solutions of ordinary differential equations with Hölder continuous forcing. We construct stochastic integrals with respect to fractional Brownian motion, and establish sufficient conditions for its existence. We prove that sto

János Kollár

Segre proved that a smooth cubic surface over Q is unirational iff it has a rational point. We prove that the result also holds for cubic hypersurfaces over any field, including finite fields.

S. M. Khoroshkin, J. Lukierski, V. N. Tolstoy

We show that the quantum affine algebra $U_{q}(A_{1}^{(1)})$ and the quantum affine superalgebra $U_{q}(C(2)^{(2)})$ admit a unified description. The difference between them consists in the phase factor which is equal to 1 for $U_{q}(A_{1}^{(1)})$ and it is equal to -1 for $U_{q}(C(2)^{(2)})$. We present such a description for the actions of the braid group,

Yu. I. Manin

The paper consists of two sections. The first section provides a new definition of mirror symmetry of abelian varieties making sense also over $p$-adic fields. The second section introduces and studies quantized theta-functions with two-sided multipliers, which are functions on non-commutative tori. This is an extension of an earlier work by the author. In t

A. Pashnev

It is shown that dynamics of D+2 elements of the (super)diffeomorphism group in one (1+1 for the super) dimension describes the D - dimensional (spinning) massless relativistic particles. The coordinates of this elements (D+2 einbeins, D+2 connections and 1 additional common coordinate of higher dimensionality) play the role of coordinates, momenta and Lagra

P. Heslop, P. S. Howe

Representations of four-dimensional superconformal groups on harmonic superfields are discussed. It is shown how various short representations can be obtained by parabolic induction. It is also shown that such short multiplets may admit several descriptions as superfields on different superspaces. In particular, this is the case for on-shell massless superfi

Klaus Kirsten

Spectral functions relevant in the context of quantum field theory under the influence of spherically symmetric external conditions are analysed. Examples comprise heat-kernels, determinants and spectral sums needed for the analysis of Casimir energies. First, we summarize that a convenient way of handling them is to use the associated zeta function. A way t

Sinji Hamamoto, Makoto Nakamura

A simple method of obtaining path-integral measures in higher-derivative gravities is presented. The measures are nothing but the generalized Lee-Yang terms.

Harold Blas

The conformal affine Toda model coupled to the matter field (CATM) is obtained through a classical reduction of the $sl(2)^{(1)}$ affine two-loop WZNW model. After spontaneously broken the conformal symmetry by means of BRST analysis, we end up with an effective theory, the so called affine Toda model coupled to the matter (ATM). Further, using a bosonizatio

Fayyazuddin

The decays $\bar{B}\to \bar{K}D$ and $\bar{B}\to \bar{K}\bar{D}$ taking into account final state interactions are discussed. These decays are described by four strong phases $δ_0, δ_1, \tildeδ_0, \tildeδ_1$ (subscript 0 and 1 refer to I=0 and I=1 isospin final states), one weak phase $γ$ and four real amplitudes. Isospin constraints are taken into account. I

X. S. Chen, X. B. Chen, Amand Faessler, Th. Gutsche

Non-conserved composite operators like the quark axial current have divergent matrix elements therefore must be renormalized. We explore how this can be done in quark model calculations where the systematic procedure of dimensional regularization and minimal subtraction is not applicable. We propose a most natural and convenient regularization scheme of cutt

S. Abdullin, M. Drees, H. -U. Martyn, G. Polesello

The results obtained by the Working Group on Supersymmetry at the 1999 Les Houches Workshop on Collider Physics are summarized. Separate chapters treat &#34;general&#34; supersymmetry, R-parity violation, gauge mediated supersymmetry breaking, and anomaly mediated supersymmetry breaking.

J. G. Korner, B. Melic

We present theoretical evidence that the exclusive/inclusive ratio of semileptonic $Λ_b$-decays exceeds that of semileptonic B-decays where the experimental exclusive/inclusive ratio amounts to about 66%. We start from the observation that the spectator quark model provides a lower bound on the leading order Isgur-Wise function of the $Λ_b \to Λ_c$ transitio

A. Bacchetta, M. Boglione, A. Henneman, P. J. Mulders

We discuss bounds on the distribution and fragmentation functions that appear at leading order in deep inelastic 1-particle inclusive leptoproduction or in Drell-Yan processes. These bounds simply follow from positivity of the quark-hadron scattering matrix elements and are an important guide in estimating the magnitude of the azimuthal and spin asymmetries

K. Fialkowski, R. Wit

We present some results concerning the Bose-Einstein effect in asymmetric sources in Monte Carlo generators. A comparison of LEP data, standard JETSET predictions and results from the weight method is given. Possible generalization of the weight factors to an asymmetric form is considered.

Yoshio Koide

As an attempt to give an unified description of quark and lepton mass matrices M_f, the following mass matrix form is proposed: the form of the mass matrices are invariant under a cyclic permutation (f_1 \to f_2, f_2 \to f_3, f_3 \to f_1) among the fermions f_i. The model naturally leads to the maximal mixing between ν_μand ν_τ, and with an additional ansatz

Osamu Yasuda

I discuss the effects of neutrino oscillations on high energy cosmic neutrinos which come from cosmologically distant astrophysical sources. I incorporate all the up-to-date constraints from the solar, atmospheric, reactor, accelerator data and give the possible pattern for the ratio of the high energy cosmic neutrinos in the cases of three and four neutrino

Osamu Yasuda

It is shown in the three flavor framework that neutrino factories enable us to measure some of the oscillation parameters, such as the sign of $Δm_{32}^2$, $θ_{13}$, $δ$. Some efforts are made to determine the parameters (the muon energy and the neutrino path length) of a neutrino factory to optimize the signals.

P. Dimopoulos, K. Farakos, G. Koutsoumbas

The Abelian Higgs model with anisotropic couplings in 2+1 dimensions is studied in both the compact and non-compact formulations. Decoupling of the space-like planes takes place in the extreme anisotropic limit, so charged particles and gauge fields are presumably localized within these planes. The behaviour of the model under the influence of an external ma

L3 Collaboration

We search for anomalous trilinear gauge couplings in the ZZgamma and Zgammagamma vertices using data collected with the L3 detector at LEP at a centre-of-mass energy \sqrt{s}=189 GeV. No evidence is found and limits on these couplings and on new physics scales are derived from the analysis of the process e+e- -> Zgamma.

L3 Collaboration

The measurements of Rb = sigma(e+e- -> bb~)/sigma(e+e- -> qq~) and of the b quark forward-backward charge asymmetry, A^b_fb, at centre-of-mass energies above the Z pole are described. The measurement of Rb is performed at \root{s} between 130 and 189 GeV using a b-tagging method that exploits the relatively large decay length of b-hadrons. The measurement of

M. Kado

The most recent results of the searches for Higgs bosons in the data taken at LEP in 1999 and their interpretation in a variety of theoretical framework are reviewed.

A. Bodek, U. K. Yang, T. Adams, A. Alton

We report on the extraction of the structure functions F2 and Delta xF3 = xF3nu-xF3nub from CCFR neutrino-Fe and antineutrino-Fe differential cross sections. The extraction is performed in a physics model independent (PMI) way. This first measurement for Delta xF3 which is useful in testing models of heavy charm production, is higher than current theoretical

Lawrence E. Kidder, Mark A. Scheel, Saul A. Teukolsky, Eric D. Carlson

Current methods of evolving a spacetime containing one or more black holes are plagued by instabilities that prohibit long-term evolution. Some of these instabilities may be due to the numerical method used, traditionally finite differencing. In this paper, we explore the use of a pseudospectral collocation (PSC) method for the evolution of a spherically sym

A. N. Aliev, Y. Nutku, K. Saygılı

We show that in the Maxwell-Chern-Simons theory of topologically massive electrodynamics the Dirac string of a monopole becomes a cone in anti-de Sitter space with the opening angle of the cone determined by the topological mass which in turn is related to the square root of the cosmological constant. This proves to be an example of a physical system, {\it a

Yi-Ping Qin

Based on some observations, the apparent energy, associated with gravity, of vacuums is defined, with that of normal vacuums to be zero and that of the vacuums losing some energy to be negative. An important application of the energy is its contribution to Einstein&#39;s equation. A cosmological model, accounting for recent observations of the accelerated ex

Pritiraj Mohanty

Light emission in sonoluminescence is shown to be a lasing process with a wide gain bandwidth. Population inversion of the gas molecules inside the bubble is achieved by hydrodynamical pumping. Analytic expressions are derived for the sonoluminescence pulse shape, pulse width, and their codependence on the spectrum and intensity in physically relevant regime

Shoji Yamamoto, Toru Sakai

Ground-state magnetization curves of ferrimagnetic Heisenberg chains of alternating spins $S$ and $s$ are numerically investigated. Calculating several cases of $(S,s)$, we conclude that the spin-$(S,s)$ chain generally exhibits $2s$ magnetization plateaux even at the most symmetric point. In the double- or more-plateau structure, the initial plateau is gene

Nino Boccara

It is shown that a variety of deterministic cellular automaton models of highway traffic flow obey a variational principle which states that, for a given car density, the average car flow is a non-decreasing function of time. This result is established for systems whose configurations exhibits local jams of a given structure. If local jams have a different s

Michele Cini, Adalberto Balzarotti, Raffaella Brunetti, Maria Gimelli

We have recently developed a canonical transformation of the Hubbard and related models, valid for systems of arbitrary size and for the full plane; this is particularly suited to study hole pairing. In this work we show that exact diagonalization results of the one band Hubbard model for small clusters with periodic boundary conditions agree well with the a

A. Aharony, O. Entin-Wohlman, Y. Imry, Y. Levinson

We present exact solutions for two interacting electrons on an artificial atom and on an artificial molecule made by one and two (single level) quantum dots connected by ideal leads. Specifically, we calculate the accumulated charge on the dots as function of the gate voltage, for various strengths of the electron-electron interaction and of the hybridizatio

Mark I. Visscher, Behzad Rejaei, Gerrit E. W. Bauer

Collective transport through a multichannel disordered conductor in contact with charge-density-wave electrodes is theoretically investigated. The statistical distribution function of the threshold potential for charge-density wave sliding is calculated by random matrix theory. In the diffusive regime weak localization has a strong effect on the sliding moti