July 2000 arXiv papers — page 13

J. O. Eeg, K. Kumericki, I. Picek

We demonstrate that in the double-radiative decays of heavy-light QED and QCD atoms, μ^{+} e^{-} \to γγand \bar{B}^{0}_{s} \to γγ, there is a contribution coming from operators that vanish on the free-quark mass shell. This off-shell effect is suppressed with respect to the effect of the well known flavour-changing magnetic-moment operator by the bound-state

V. Barger, S. Geer, R. Raja, K. Whisnant

Within the framework of three-neutrino and four-neutrino scenarios that can describe the results of the LSND experiment, we consider the capabilities of short baseline neutrino oscillation experiments at a neutrino factory. We find that, when short baseline ($L \alt 100$ km) neutrino factory measurements are used together with other accelerator-based oscilla

Michael Kobel, Zbigniew Was, C. Ainsley, A. Arbuzov

This report summarizes the results of the two-fermion working group of the LEP2-MC workshop, held at CERN from 1999 to 2000. Recent developments in the theoretical calculations of the two fermion production process in the electron-positron collision at LEP2 center of the mass energies are reported. The Bhabha process and the production of muon, tau, neutrino

W. Buchmüller, M. Plümacher

Due to sphaleron processes in the high-temperature symmetric phase of the standard model the cosmological baryon asymmetry is related to neutrino properties. For hierarchical neutrino masses, with $B-L$ broken at the unification scale $Λ_{GUT}\sim 10^{16} $GeV, the observed baryon asymmetry $n_B/s \sim 10^{-10}$ can be naturally explained by the decay of hea

S. Digal, E. Laermann, H. Satz

We propose that in QCD with dynamical quarks, colour deconfinement occurs when an external field induced by the chiral condensate strongly aligns the Polyakov loop. This effect sets in at the chiral symmetry restoration temperature T-chi and thus makes deconfinement and chiral symmetry restoration coincide. The predicted singular behaviour of Polyakov loop s

A. Djouadi, Y. Mambrini

We analyze the decays of charginos, neutralinos, gluinos and the first/second generation squarks in the Minimal Supersymmetric extension of the Standard Model, focusing on the three-body decays in scenarios where the ratio $\tan β$ of vacuum expectation values of the two Higgs doublet fields is large. We show that the three-body decays of the next-to-lightes

Teiji Kunihiro

We discuss the baryon-number susceptibility $χ_B$ and related topics which include the density fluctuations around the critical point of the chiral transition at finite temperature $T$ and baryon density $ρ_B$. Phenomenological implications of the density fluctuations near the first-order chiral transition at finite density are also discussed.

J. A. Gracey

The anomalous dimensions of the general flavour non-singlet quark bilinear currents ψγ^{[μ_1} ... γ^{μ_n]} ψare computed at three loops in quantum chromodynamics in the minimal subtraction scheme. The dimension of the tensor current emerges for the case n = 2 and the anomalous dimension for the general flavour singlet current is also discussed.

N. C. Tsamis, R. P. Woodard

Schwinger used an analytic continuation of the effective action to correctly compute the particle production rate per unit volume for QED in a uniform electric field. However, if one simply evaluates the one loop expectation value of the current operator using his propagator, the result is zero! We analyze this curious fact from the context of a canonical fo

T. N. Tomaras, N. C. Tsamis, R. P. Woodard

We consider the back-reaction of quantum electrodynamics upon an electric field E(x_+) = - A'_-(x_+) which is parallel to x^3 and depends only on the lightcone coordinate x_+ = (x^0 + x^3)/\sqrt{2}. Novel features are that the mode functions have simple expressions for arbitrary A_-(x_+), and that one cannot ignore the usual lightcone ambiguity at zero +

Stefano Bertolini

I shortly review the present status of the theoretical estimates of eps'/eps. I consider a few aspects of the theoretical calculations which may be relevant in understanding the present experimental results. In particular, I discuss the role of final state interactions and in general of non-factorizable contributions for the explanation of the Delta I =

Kenneth Lane

We briefly review the basic structure of modern--day technicolor theories. We then discuss the signatures for technicolor as they were in its early days, the searches that have been recently performed at the Tevatron and LEP colliders, and the prospects for testing technicolor in Tevatron Run II and at the LHC.

W. Anthony Mann

Neutrino interactions recorded in a 5.1 fiducial kiloton-year exposure of the Soudan-2 iron tracking calorimeter are analyzed for effects of neutrino oscillations. Using contained single track and single shower events, we update our measurement of the atmospheric nu_mu/nu_e ratio-of-ratios and find R = 0.68 \pm 0.11 \pm 0.06. Assuming this anomalously low R-

K. B. Luk, H. T. Diehl, J. Duryea, G. Guglielmo

A search for direct CP violation in the non-leptonic decays of hyperons has been performed. In comparing the product of the decay parameters, $α_Ξα_Λ$, in terms of an asymmetry parameter, $A_{ΞΛ}$, between hyperons and anti-hyperons in the charged $Ξ\to Λπ$ and $Λ\to p π$ decay sequence, we found no evidence of direct CP violations. The parameter $A_{ΞΛ}$ wa

A. W. Thomas

We summarize the theoretical consensus of the HiX workshop concerning those measurements which seem most appropriate for inclusion in the ``white paper'' being prepared to justify the proposed 12 GeV upgrade at Jefferson Lab. The criteria for inclusion are that such measurements should be decisive, not possible elsewhere and should answer crucial phy

Norman Cruz, Cristian Martinez

We examine Friedmann-Robertson-Walker models in three spacetime dimensions. The matter content of the models is composed of a perfect fluid, with a $γ$-law equation of state, and a homogeneous scalar field minimally coupled to gravity with a self-interacting potential whose energy density red-shifts as $a^{-2 ν}$, where a denotes the scale factor. Cosmologic

D. H. Coule

We contrast the possibility of inflation starting a) from the universe's inception or b) from an earlier non-inflationary state. Neither case is ideal since a) assumes quantum mechanical reasoning is straightforwardly applicable to the early universe; while case b) requires that a singularity still be present. Further, in agreement with Vachaspati and Tr

Joao Magueijo

We propose definitions for covariance and local Lorentz invariance applicable when the speed of light $c$ is allowed to vary. They have the merit of retaining only those aspects of the usual definitions which are invariant under unit transformations, and which can therefore legitimately represent the outcome of an experiment. We then discuss some possibiliti

Yan Levin

We present a simple argument to account for crystallization of hard spheres under the action of a gravitational field. The paper attempts to bridge the gap between two communities of scientists, one working on granular materials and the other on inhomogeneous liquid state theory.

Philip W. Anderson

We find experimental evidence for spin-charge separation in all four relevant phases of the cuprates. It is argued that this phenomenon serves to protect the properties of the cuprates from the effects of impurities and phonons.

A. Ciach, G. Stell

A Landau-Ginzburg functional of two order parameters (charge-density $ϕ$ and mass-density deviation $η$) is developed in order to yield a field theory relevant to ionic lattice gases as well as a family of off-lattice models of ionic fluids that go beyond the restricted primitive model (RPM). In a mean-field (MF) approximation an instability of a uniform pha

T. Becker, M. Gabay, T. Giamarchi

We obtain the Knight shifts and the relaxation rates related to the Fermi contact interaction term for a one-dimensional Cu-O model using bosonization technique. We consider the small interaction limit at half-filling and away from half-filling. In this framework we predict that the antiferromagnetic contribution to the relaxation rate of the nuclear oxygen

V. V. Kabanov, D. Mihailovic

We consider finite-k electron-phonon coupling appropriate for a superconductor with a very short coherence length and local intersite pairs. From group theoretical analyis we find that phonons with nonzero k can couple to degenerate electronic states in LaSrCuO and a Jahn-Teller-like distortion is found to be operative for E_u and E_g -symmetry O states. Exp

Sang Koo You, Chul Koo Kim, Kyun Nahm, Hyun Sik Noh

A variational Perturbation theory based on the functional integral approach is formulated for many-particle systems. Using the variational action obtained through Jensen-Peierls' inequality, a perturbative expansion scheme for the thermodynamic potential is established. A modified Wick's theorem is obtained for the variational perturbation expansions

A Lamacraft, B D Simons

A field theoretic approach is developed to investigate the profile and spectrum of sub-gap states in a superconductor subject to a weak magnetic impurity potential. Such states are found to be associated with inhomogeneous supersymmetry broken instanton configurations of the action.

G. Brown, M. A. Novotny, P. A. Rikvold

Numerical integration of the Landau-Lifshitz-Gilbert equation with thermal fluctuations is used to study the dynamic response of single-domain nanomagnets to rapid changes in the applied magnetic field. The simulation can resolve magnetization patterns within nanomagnets and uses the Fast Multipole method to calculate dipole-dipole interactions efficiently.

V. T. Petrashov, I. A. Sosnin, C. Troadec

We find that the dependence on temperature and magnetic field of the electrical resistance of diffusive ferromagnetic nano-wires measured with superconducting electrodes changes drastically with the distance, $L$, between the ferromagnet/superconductor contacts, however is remarkably similar for the wires with the same $L$ ranging from 300 nm to 1000 nm, pre

A. Bansil, B. Barbiellini

Compton scattering is one of the few spectroscopies which directly probes the ground state momentum density in materials. Recent progress in synchrotron light sources has brought a renewed interest in the technique as a tool for investigating fermiology related issues on the one hand, and as a unique window on hitherto inaccessible correlation effects in the

A. Winkler, A. Latz, R. Schilling, C. Theis

We study the molecular mode coupling theory for a liquid of diatomic molecules. The equations for the critical tensorial nonergodicity parameters ${\bf F}_{ll'}^m(q)$ and the critical amplitudes of the $β$ - relaxation ${\bf H}_{ll'}^m(q)$ are solved up to a cut off $l_{co}$ = 2 without any further approximations. Here $l,m$ are indices of spherical

K. Haule, S. Kirchner, J. Kroha, P. Wölfle

We have developed a self-consistent conserving pseudo particle approximation for the Anderson impurity model with finite Coulomb interaction, derivable from a Luttinger Ward functional. It contains an infinite series of skeleton diagrams built out of fully renormalized Green's functions. The choice of diagrams is motivated by the Schrieffer Wolff transfo

M. Fuchs, K. S. Schweizer

The change of the structure of concentrated colloidal suspensions upon addition of non-adsorbing polymer is studied within a two-component, Ornstein-Zernicke based liquid state approach. The polymers' conformational degrees of freedom are considered and excluded volume is enforced at the segment level. The polymer correlation hole, depletion layer, and e

S. F. Edwards, H. Takano, E. M. Terentjev

The dynamic-mechanical response of flexible polymer networks is studied in the framework of tube model, in the limit of small affine deformations, using the approach based on Rayleighian dissipation function. The dynamic complex modulus G* is calculated from the analysis of a network strand relaxation to the new equilibrium conformation around the distorted

F. Dominguez-Adame

We present a model for a class of random binary lattices by introducing a one-dimensional system where impurities are placed in one sublattice while host atoms lie on the other sublattice. The source of disorder is the stochastic fluctuation of the impurity energy from site to site. We study the optical absorption spectra and the peculiarities of the motiona

A. A. Petrova

Dynamics of bending of NaCl whisker is studied with use of high speed camera VFU-1 synchronized with high power electron accelerator GIN-600. The dynamics of bending turns to be non-monotonous and quite complicated. The figures of etching of whisker after bombardment by electron beam are analysed, thin polygonization in samples is found. The time of bending

Lei-Han Tang, Zhi-Feng Huang

The minute-by-minute move of the Hang Seng Index (HSI) data over a four-year period is analysed and shown to possess similar statistical features as those of other markets. Based on a mathematical theorem [S. B. Pope and E. S. C. Ching, Phys. Fluids A {\bf 5}, 1529 (1993)], we derive an analytic form for the probability distribution function (PDF) of index m

Igor F. Herbut

The equation for the wave-function localization length in terms of the two-point correlation function of a weak random potential in 1D (F. M. Izrailev and A. A. Krokhin, Phys. Rev. Lett. vol. 82, 4062 (1999)) is rederived using the standard weak-localization theory. I propose a modified algorithm for generation of arbitrary correlated random potentials, and

K. Ishikawa, N. Maeda

Pressure, compressibility, and Hall conductance of anisotropic states at higher Landau levels are computed. Pressure and compressibility become negative. Hall conductance is unquantized and varies with filling factor. These facts agree with the recent experimental observations of highly anisotropic compressible states at higher Landau levels. It is shown, as

K. Noguchi, T. Tajima, R. Matsumoto

The stability of nonaxisymmetric perturbations in differentially rotating astrophysical accretion disks is analyzed by fully incorporating the properties of shear flows. We verify the presence of discrete unstable eigenmodes with complex and pure imaginary eigenvalues, without any artificial disk edge boundaries, unlike Ogilvie & Pringle(1996)'s claim. B

István Szapudi, Enzo Branchini, C. S. Frenk, Steve Maddox

We investigate the spatial clustering of galaxies in the PSCz galaxy redshift survey, as revealed by the two-point correlation function, the luminosity mark correlations, and the moments of counts-in-cells. We construct volume-limited subsamples at different depths, and search for a luminosity dependence of the clustering pattern. We find no statistically si

D. V. Bizyaev

Photometric parameters of stellar disks and bulges for several edge-on galaxies from the Catalog of Flat Galaxies (FGC) were determined. We discuss a difference between photometric parameters of LSB and HSB galaxies from our sample. Also we present results of R CCD photometry of edge-on galaxy RFGC 3647. Deprojecting this galaxy we show that it has thin LSB

Carme Gallart

I discuss the information provided by color-magnitude diagrams of different absolute magnitude limits in the study of the star formation histories of nearby galaxies. I review the recent progress made in the field, with emphasis on the results for Local Group dwarf galaxies.

George Sonneborn, Todd M. Tripp, Roger Ferlet, Edward B. Jenkins

To measure interstellar atomic deuterium abundances, we used the Interstellar Medium Absorption Profile Spectrograph (IMAPS) to obtain spectra of gamma2 Vel and zeta Pup over the wavelength interval 930-1150 A at a resolving power of 80,000. The interstellar D I features are resolved and cleanly separated from interstellar H I in the Ly-delta and Ly-epsilon

J. Christopher Howk, Kenneth R. Sembach, Katherine C. Roth, Jeffrey W. Kruk

We report empirical determinations of atomic oscillator strengths, or f-values, for 11 ground-state transitions of Fe II in the wavelength range 1050 to 1150 Ang. We use ultraviolet absorption line observations of interstellar material towards stars in the Galaxy and the Magellanic Clouds taken with Copernicus, the Goddard High Resolution Spectrograph on-boa

I. N. Reid, S. Mahoney

We have used the HIRES echelle spectrograph in the Keck I telescope to obtain high-resolution spectroscopy of 51 late-type M dwarfs in the Hyades cluster. Cross-correlating the calibrated data against spectra of white dwarfs allows us to determine heliocentric velocities with an accuracy of +/- 0.3 km/s. Twenty seven stars were observed at two epochs in 1997

M. Coleman Miller

Observations with RXTE have revealed kilohertz quasi-periodic brightness oscillations (QPOs) from nearly twenty different neutron-star low-mass X-ray binaries (LMXBs). These frequencies often appear as a pair of kilohertz QPOs in a given power density spectrum. In many models the higher-frequency of these QPOs is a beaming oscillation at the frequency of a n

J. M. Cordes

I use a method based on interstellar scintillations for discerning information about source sizes on scales less than one micro-arc sec. I use a comprehensive model for a pulsar signal, scintillated amplitude modulated noise, that includes source fluctuations and noise statistics. The method takes into account time-frequency averaging in the signal processin

P. L. Hammersley, F. Garzon, T. Mahoney, M. Lopez-Corredoira

We present near-IR colour--magnitude diagrams and star counts for a number of regions along the Galactic plane. It is shown that along the l=27 b=0 line of sight there is a feature at 5.7 +-0.7kpc with a density of stars at least a factor two and probably more than a factor five times that of the disc at the same position. This feature forms a distinct clump

J. M. Cordes

Interstellar scintillation can be used to probe transverse sizes of radio sources on scales inaccessible to the nominal resolution of any terrestrial telescope, e.g. $\lesssim 10^{-6}$ arc sec. Methodology is presented that exploits this superresolution phenomenon for both single aperture and interferometer observations. The treatment applies to the saturate

J. Dickel, D. Milne, R. Strom

High resolution radio observations of the composite supernova remnant (SNR) G326.3-1.8 or MSH 15-56 with the Australia Telescope Compact Array show details of both the shell and the bright plerion which is offset about 1/3 of the distance from the center of the SNR to the shell. The shell appears to be composed of thin filaments, typical of older shell SNRs.

S. Mereghetti, R. P. Mignani, S. Covino, S. Chaty

We have carried out a search for the optical and infrared counterpart of the Anomalous X-ray Pulsar 1E 1841-045, which is located at the center of the supernova remnant Kes73. We present the first deep optical and infrared images of the field of 1E 1841-045, as well as optical spectroscopy results that exclude the brightest objects in the error circle as pos

A. Mathieu, M. R. Merrifield

We present a method for recovering the distribution functions of edge-on thin axisymmetric disks directly from their observable kinematic properties. The most generally observable properties of such a stellar system are the line-of-sight velocity distributions of the stars at different projected radii along the galaxy. If the gravitational potential is known

M. Fellhauer, P. Kroupa, H. Baumgart, R. Bien

We present Superbox, a particle-mesh code with high resolution sub-grids and an NGP (nearest grid point) force-calculation scheme based on the second derivatives of the potential. Superbox implements a fast low-storage FFT-algorithm, giving the possibility to work with millions of particles on desk-top computers. Test calculations show energy and angular mom

G. A. Gurzadyan

The dynamics of a close binary system of globular clusters is considered. It is shown that the star transfer process from one of the components to the other should lead to the decrease of dimension of the first cluster with simultaneous increase of the dimension of the second cluster. The rates of variations of clusters' sizes due to the mutual tidal int

H. J. McCracken, T. Shanks, N. Metcalfe, R. Fong

(abridged) We present a study of the angular correlation function as measured in the William Herschel Deep Field. This field covers 50 arcmin$^2$ and with it we are able to investigate the scaling of the angular correlation function to $B\sim28$, $R, I\sim 26$,$K\sim20$ and $H\sim22.5$. We compare our measurements to results obtained from the smaller Hubble

R. J. Wilman, A. C. Edge, R. M. Johnstone, C. S. Crawford

We present J, H and K-band spectroscopy of Cygnus A, spanning 1.0-2.4 micron in the rest-frame and hence several rovibrational H2, H recombination and [FeII] emission lines. The lines are spatially extended by up to 6kpc from the nucleus, but their distinct kinematics indicate that the three groups (H, H2 and [FeII]) are not wholly produced in the same gas.

Paolo A. Mazzali, Koichi Iwamoto, Ken'ichi Nomoto

The properties of the bright and energetic Type Ic SN 1997ef are investigated using a Monte Carlo spectrum synthesis code. Analysis of the earliest spectra is used to determine the time of outburst. The changing features of the spectrum and the light curve are used to probe the ejecta and to determine their composition, verifying the results of explosion cal

S. Nishiura, T. Murayama, M. Shimada, Y. Sato

In order to investigate the dynamical status of Seyfert's Sextet (SS), we have obtained a deep optical ($VR+I$) image of this group. Our image shows that a faint envelope, down to a surface brightness $μ_{\rm optical}$(AB) $\simeq 27$ mag arcsec$^{-2}$, surrounds the member galaxies. This envelope is irregular in shape. It is likely that this shape is at

T. G. Griffiths, E. Comforti, M. Heiblum, Ady Stern

The charge of quasiparticles in a fractional quantum Hall (FQH) liquid, tunneling through a partly reflecting constriction with transmission t, was determined via shot noise measurements. In the nu=1/3 FQH state, a charge smoothly evolving from e*=e/3 for t=1 to e*=e for t<<1 was determined, agreeing with chiral Luttinger liquid theory. In the nu=2/5 FQH sta

Gen Yoneda, Hisa-aki Shinkai

We study asymptotically constrained systems for numerical integration of the Einstein equations, which are intended to be robust against perturbative errors for the free evolution of the initial data. First, we examine the previously proposed &#34;$λ$-system&#34;, which introduces artificial flows to constraint surfaces based on the symmetric hyperbolic form

Jerome P. Gauntlett, David Tong, Paul K. Townsend

The general scalar potential of D-dimensional massive sigma-models with eight supersymmetries is found for $D=3,4$. These sigma models typically admit 1/2 supersymmetric domain wall solutions and we find, for a particular hyper-Kähler target, exact 1/4 supersymmetric static solutions representing a non-trivial intersection of two domain walls. We also show t

F. Gerbier, P. Bouyer, A. Aspect

We analyse the extraction of a coherent atomic beam from a trapped Bose-Einstein condensate using a rf transition to a non-trapping state at T=0 K. Our quantum treatment fully takes gravity into account but neglects all interactions in the free falling beam. We obtain an analytical expression of the output rate and of the wave function of the extracted beam,

Maarten Golterman, Yigal Shamir

We consider overlap-Dirac fermions at non-zero bare coupling and for a small hopping parameter, or, equivalently, large $|M|$ with $M$ the domain-wall height. We prove the existence of a phase at large positive $M$ where the abelian axial group $U_A(1)$ is a symmetry, and the corresponding pseudo-scalar is an exact Goldstone boson. We also provide a conjectu

R. Kemmoku, H. T. Sato

Studied is the deformation of super Virasoro algebra proposed by Belov and Chaltikhian. Starting from abstract realizations in terms of the FFZ type generators, various connections of them to other realizations are shown, especially to deformed field representations, whose bosonic part generator is recently reported as a deformed string theory on a noncommut

M. R. Setare, A. H. Rezaeian

The Casimir energy for scalar field of two parallel conductor in two dimensional domain wall background, with Dirichlet boundary conditions, is calculated by making use of general properties of renormalized stress tensor.We show that vacuum expectation values of stress tensor contain two terms which come from the boundary conditions and the gravitational bac

Diederik Aerts, Jan Broekaert, Sonja Smets

In this paper we concentrate on the nature of the liar paradox as a cognitive entity; a consistently testable configuration of properties. We elaborate further on a quantum mechanical model [Aerts, Broekaert, Smets 1999] that has been proposed to analyze the dynamics involved, and we focus on the interpretation and concomitant philosophical picture. Some con

L. Alvarez-Ruso, M. B. Barbaro, T. W. Donnelly, A. Molinari

Impulsive hadronic descriptions of electroweak processes in nuclei involve two distinctly different elements: one stems from the nuclear many-body physics --- the medium --- which is rather similar for the various inclusive response functions, and the other embodies the responses of the hadrons themselves to the electroweak probe and varies with the channel

Mircea Mustata, Gregory G. Smith, Harrison Tsai, Uli Walther

Let X be a smooth toric variety. David Cox introduced the homogeneous coordinate ring S of X and its irrelevant ideal B. Extending well-known results on projective space, Cox established the following: (1) the category of quasi-coherent sheaves on X is equivalent to the category of graded S-modules modulo B-torsion, (2) the variety X is a geometric quotient

Jin Min Yang, Bing-Lin Young

The light stop pair if produced in hadron colliders and decaying through the likely decay chain stop->chargino + b followed by chargino->neutralino + f f&#39;, can mimic closely a top quark event when the mass of the stop is close to that of the top quark. Because of the much lower production rate, the stop event can be buried under the top quark event sampl

E. del Barco, J. M. Hernandez, J. Tejada, N. Biskup

Precise resonant experiments on Fe$_{8}$ magnetic clusters have been conducted down to 1.2 K at various tranverse magnetic fields, using a cylindrical resonator cavity with 40 different frequencies between 37 GHz and 110 GHz. All the observed resonances for both single crystal and oriented powder, have been fitted by the eigenstates of the hamiltonian ${\cal

R. J. McLure, J. S. Dunlop

The spatial clustering amplitude (B_{gq}) is determined for a sample of 44 powerful AGN at z~0.2. No significant difference is detected in the richness of the cluster environments of the radio-loud and radio-quiet sub-samples, both of which typically inhabit environments as rich as Abell Class ~0. Comparison with radio luminosity-matched samples from Hill &

De-Hai Zhang

Boomerang measured the first peak in CMBR to be at location of $l_D=196\pm 6$, which excites our strong interesting in it. A widely cited formula is $l_D\simeq 200Ω_T^{-0.50}$ to estimate the cosmic total density. Weinberg shows it is not correct and should be $l_D\propto Ω_T^{-1.58}$ near the interest point $(Ω_m,Ω_Λ)=(0.3,0.7)$. We show further that it sho

Y. Shi

As a response to ligand binding, transmembrane cell receptors often enhance their clustering, or oligomerization, during the signalling process. Here we present a statistical mechanical model which combines the aspects of clustering and signalling. In this model, receptors float on the surface, while for two neighboring receptors, there is an interaction ene

Riazuddin, T. A. Al-Aithan, Amjad Hussain Shah Gilani

The form factors for the $B-->π$ transition are evaluated in the entire momentum transfer range by using the constraints obtained in the framework combining the heavy quark expansion and chiral symmetry for light quarks and the quark model. In particular, we calculate the valence quark contributions and show that it together with the equal time commutator co

T. Scopigno, U. Balucani, G. Ruocco, F. Sette

An inelastic X-ray scattering experiment has been performed in liquid aluminum with the purpose of studying the collective excitations at wavevectors below the first sharp diffraction peak. The high instrumental resolution (up to 1.5 meV) allows an accurate investigation of the dynamical processes in this liquid metal on the basis of a generalized hydrodynam

B. Ponsot, J. Teschner

The decomposition of tensor products of representations into irreducibles is studied for a continuous family of integrable operator representations of $U_q(sl(2,R)$. It is described by an explicit integral transformation involving a distributional kernel that can be seen as an analogue of the Clebsch-Gordan coefficients. Moreover, we also study the relation

A. F. Lisetskiy, N. Pietralla, C. Fransen, R. V. Jolos

Shell model calculations have been performed for the nucleus 94Mo. The calculated excitation energies and electromagnetic properties of low-lying states are in good agreement with the data, which include states with mixed-symmetry (MS) assignments in previous interacting boson model studies. In the shell model large isoscalar E2 matrix elements are found bet

E. S. Cheb-Terrab, T. Kolokolnikov

An algorithm for solving first order ODEs, by systematically determining symmetries of the form [ xi = F(x), eta = P(x) y + Q(x) ], where xi d/dx + eta d/dy is the symmetry generator - is presented. To these {\it linear} symmetries one can associate an ODE class which embraces all first order ODEs mappable into separable through linear transformations {t = f

Paul J. Huizinga

The property that a one to one function from the natural numbers to itself preserves the density of sub-sets is shown to be equivalent to a condition on the covering of intervals in the range of the function by images of intervals in the domain of the function.

Alan Horwitz

Let m(a,b) and M(a,b,c) be symmetric means. We say that M is type 1 invariant with respect to m if M(m(a,c),m(a,b),m(b,c)) = M(a,b,c) for all a, b, c > 0. If m is strict and isotone, then we show that there exists a unique M which is type 1 invariant with respect to m. In particular we discuss the invariant logarithmic mean L_3, which is type 1 invariant wit

F. Bruckmann, T. Heinzl, T. Vekua, A. Wipf

We investigate the Laplacian Abelian gauge on the sphere S^4 in the background of a single `t Hooft instanton. To this end we solve the eigenvalue problem of the covariant Laplace operator in the adjoint representation. The ground state wave function serves as an auxiliary Higgs field. We find that the ground state is always degenerate and has nodes. Upon di

Massimo Giovannini

The dynamical evolution of internal space-like dimensions breaks the invariance of the Maxwell&#39;s equations under Weyl rescaling of the (conformally flat) four-dimensional metric. Depending upon the number and upon the dynamics of internal dimensions large scale magnetic fields can be created. The requirements coming from magnetogenesis together with the

Chao-Hsi Chang, Shao-Long Chen, Tai-Fu Feng, Xue-Qian Li

The lifetime of the B_c-meson is estimated with consistent considerations on all of the heavy mesons ($B^0, B^\pm, B_s, D^0, D^\pm D_s$) and the double heavy meson B_c. In the estimate, the framework, where the non-spectator effects for nonleptonic decays are taken into account properly, is adopted, and the parameters needed to be fixed are treated carefully

John Ellis

A personal view of current prospectives in particle physics is presented, inspired by the contributions to this meeting. Particular emphasis is laid in precision tests of the Standard Model and the search for the Higgs boson, on probes of CP violation, on speculations about possible physics beyond the Standard Model, on neutrino masses and oscillations, on t

Leor Barack, Lior M. Burko

We calculate the self force acting on a scalar particle which is falling radially into a Schwarzschild black hole. We treat the particle&#39;s self-field as a linear perturbation over the fixed Schwarzschild background. The force is calculated by numerically solving the appropriate wave equation for each mode of the field in the time domain, calculating its

L. G. Boussiakou, C. R. Bennett, M. Babiker

The Hamiltonian of a moving atom in electromagnetic fields includes velocity- dependent terms. We show that the leading velocity dependence emerges systematically in the non-relativistic limit from a scheme firmly based on the relativistic invariance of the energy-momentum stress tensor of the coupled matter-fields system. We then extend the Hamiltonian to t

M. Azzouz

The paramagnetic phase of the one-dimensional Kondo lattice model is investigated for electron densities below half-filling using a new mean-field approach. The physical parameters that govern this phase are identified to be the spin-flip processes of both the localized and itinerant spins. A nonmagnetic quantum state, where the local magnetization is a rota

B. Bock, M. Azzouz

We extend the definition of the Jordan-Wigner transformation to three dimensions using the generalization of ideas that were used in the two-dimensional case by one of the present authors. Under this transformation, the 3D XY Hamiltonian is transformed into a system of spinless fermions coupled to a gauge field with only two components. We calculate the flux

Romeel Davé, Renyue Cen, Jeremiah P. Ostriker, Greg L. Bryan

Approximately 30-40% of all baryons in the present day universe reside in a warm-hot intergalactic medium (WHIM), with temperatures between 10^5<T<10^7 K. This is a generic prediction from six hydrodynamic simulations of currently favored structure formation models having a wide variety of numerical methods, input physics, volumes, and spatial resolutions. M

Guenter Wiedemann, Drake Deming, Gordon Bjoraker

We have searched for a methane signature in the infrared spectrum of tau Bootis, produced by the planetary companion. The observations comprise 598 low-noise, high resolution spectra near 3.28 microns, which we analyze by cross-correlating with a modeled planetary spectrum based on the work of Burrows and Sharp (1999), and Sudarsky et al. (2000). The 3-sigma

E. A. Evstigneeva, V. P. Reshetnikov, N. Ya. Sotnikova

We present an analysis of interacting E/S0 galaxies location on the Fundamental Plane. Using the NEMO package, we performed N-body simulations of close encounters and mergers between two spherical galaxies. We followed how structural and dynamical parameters (central density, half-mass radius and velocity dispersion)of galaxies are changed during the encount

Anne-Christine Davis, Konstantinos Dimopoulos, Tomislav Prokopec, Ola Tornkvist

We show that conformal invariance of gauge fields is naturally broken in inflation, having as a consequence amplification of gauge fields. The resulting spectrum of the field strength is approximately B_L ~ L^(-1), where L is the relevant coherence scale. One realisation of our scenario is scalar electrodynamics with a scalar whose mass is large enough to ev

J. H. P. Wu, A. Balbi, J. Borrill, P. G. Ferreira

We propose a new formalism to handle asymmetric beams in the data analysis of cosmic microwave background anisotropy experiments. For any beam shape, the formalism finds the optimal circularly symmetric equivalent and is thus easily adaptable to existing data analysis methods. We demonstrate certain key points by using a simulated highly elliptic beam, and t

Jens O. Andersen, Eric Braaten, Michael Strickland

The thermal physics of a massless scalar field with a phi^4 interaction is studied within screened perturbation theory (SPT). In this method the perturbative expansion is reorganized by adding and subtracting a mass term in the lagrangian. We consider several different mass prescriptions that generalize the one-loop gap equation to two-loop order. We calcula

Kurt Broderix, Kamal K. Bhattacharya, Andrea Cavagna, Annette Zippelius

Molecular dynamics simulations are used to generate an ensemble of saddles of the potential energy of a Lennard-Jones liquid. Classifying all extrema by their potential energy u and number of unstable directions k, a well defined relation k(u) is revealed. The degree of instability of typical stationary points vanishes at a threshold potential energy, which

N. Read, Andreas W. W. Ludwig

When the two-dimensional random-bond Ising model is represented as a noninteracting fermion problem, it has the same symmetries as an ensemble of random matrices known as class D. A nonlinear sigma model analysis of the latter in two dimensions has previously led to the prediction of a metallic phase, in which the fermion eigenstates at zero energy are exten

J. F. Gomes, E. P. Gueuvoghlanian, G. M. Sotkov, A. H. Zimerman

A general construction of affine Non Abelian (NA) - Toda models in terms of axial and vector gauged two loop WZNW model is discussed. They represent {\it integrable perturbations} of the conformal $σ$-models (with tachyons included) describing (charged) black hole type string backgrounds. We study the {\it off-critical} T-duality between certain families of

Ilya A. Gruzberg, N. Read, Andreas W. W. Ludwig

We consider a classical random-bond Ising model (RBIM) with binary distribution of $\pm K$ bonds on the square lattice at finite temperature. In the phase diagram of this model there is the so-called Nishimori line which intersects the phase boundary at a multicritical point. It is known that the correlation functions obey many exact identities on this line.

A. Smette, A. S. Fruchter, T. R. Gull, K. C. Sahu

We present HST/STIS observations of the optical counterpart (OT) of the gamma-ray burster GRB 000301C obtained on 2000 March 6, five days after the burst. CCD clear aperture imaging reveals a R ~ 21.50+/-0.15 source with no apparent host galaxy. An 8000 s, 1150 < lambda/A < 3300 NUV-MAMA prism spectrum shows a relatively flat continuum (in f_lambda) between

L. H. Li, S. Sofia

We argue that a variety of solar data suggest that the activity-cycle timescale variability of the total irradiance, is produced by structural adjustments of the solar interior. Assuming these adjustments are induced by variations of internal magnetic fields, we use measurements of the total irradiance and effective temperature over the period from 1978 to 1

Ted Jacobson, David Mattingly

We study a generally covariant model in which local Lorentz invariance is broken "spontaneously" by a dynamical unit timelike vector field $u^a$---the "aether". Such a model makes it possible to study the gravitational and cosmological consequences of preferred frame effects, such as ``variable speed of light" or high frequency dispersion, while preserving a