September 2000 arXiv papers — page 16

A. Kempf

In most inflationary models, space-time inflated to the extent that modes of cosmological size originated as modes of wavelengths at least several orders of magnitude smaller than the Planck length. Recent studies confirmed that, therefore, inflationary predictions for the cosmic microwave background perturbations are generally sensitive to what is assumed a

Rene A. Mendez, Maria T. Ruiz

White dwarf cooling sequences provides a useful indicator of the evolutionary time scales involved in the chronometry and star formation history of the galactic disk and, for this reason, the luminosity function of white dwarfs has become a powerful tool for studies of the evolution and formation of the Milky Way. We examine the faint-end ($M_V > +14$) behav

Jeremy Darling, Riccardo Giovanelli

We present the current results of a survey for OH megamasers (OHMs) underway at the Arecibo Observatory. The survey is 2/3 complete and has produced a high OHM detection rate (1 in 6) from a redshift-selected sample of IRAS galaxies. The survey will relate the OHM luminosity function to the galaxy merger rate, allowing subsequent blind OHM surveys to measure

L. Sodre, D. Proust, H. V. Capelato, G. B. Lima Neto

We present a dynamical analysis of the galaxy cluster Abell 970 based on a new set of radial velocities measured at ESO, Pic du Midi and Haute-Provence observatories. Our analysis indicates that this cluster has a substructure and is out of dynamical equilibrium. This conclusion is also supported by differences in the positions of the peaks of the surface de

D. Watson, N. Smith, L. Hanlon, B. McBreen

The high redshift (z=0.997) blazar B2 1308+326 was observed contemporaneously at x-ray, optical and radio wavelengths in June 1996. The x-ray observations were performed with ASCA. The ASCA results were found to be consistent with reanalysed data from two earlier ROSAT observations. The combined ASCA and ROSAT data reveal an x-ray spectrum that is best fit b

M. Cappi, P. Mazzotta, M. Elvis, D. J. Burke

We present results from a Chandra X-ray Observatory study of the field X-ray source populations in 4 different observations: two high-redshift (z~0.5) clusters of galaxies 3C295 and RXJ003033.2+261819; and two non-cluster fields with similar exposure time. Surprisingly, the 0.5-2 keV source surface densities (~900-1200 sources deg**-2 at a flux limit of 1.5x

O. Chesneau, M. Roche, A. Boccaletti, L. Abe

We obtained Halpha diffraction limited data of the LBV star P Cyg using the ONERA Adaptive Optics (AO) facility BOA at the OHP 1.52m telescope on October 1997. Taking P Cyg and the reference star 59 Cyg AO long exposures we find that P Cyg clearly exhibits a large and diffuse intensity distribution compared to the 59 Cyg's point-like source. A deconvolut

Jane Charlton, Karen Knierman, Sally Hunsberger, Sarah Gallagher

Star clusters can be found in galaxy mergers, not only in central regions, but also in the tidal debris. In both the Eastern and Western tidal tails of NGC 3256 there are dozens of young star clusters, confirmed by their blue colors and larger concentration index as compared to sources off of the tail. Tidal tails of other galaxy pairs do not have such wides

P. de Vicente, J. Martin-Pintado, R. Neri, P. Colom

We present single dish and interferometric maps of several rotational transitions of HC3N vibrationally excited levels towards Sgr B2. The single dish maps show, for the first time, new four bright clumps (Sgr B2R1 to B2R4) in the ridge connecting the main cores Sgr B2M and Sgr B2N, and a low brightness extended region to the west of the ridge (Sgr B2W). The

T. Foglizzo, M. Tagger

A new instability mechanism is described in accretion flows where the gas is accelerated from a stationary shock to a sonic surface. The instability is based on a cycle of acoustic and entropic waves in this subsonic region of the flow. When advected adiabatically inward, entropy perturbations trigger acoustic waves propagating outward. If a shock is present

Ari Laor

The distribution of radio to optical fluxes in AGN is bimodal. The physical origin for this bimodality is not understood. In this Letter I describe observational evidence, based on the Boroson & Green PG quasar sample, that the radio loudness bimodality is strongly related to the black hole mass (M_BH). Nearly all PG quasars with M_BH>10^9M_sun are radio lou

Nelson Vera-Villamizar, Horacio Dottori, Ivanio Puerari, Reinaldo de Carvalho

We have searched for corotations (CR) in three Southern grand design spiral galaxies: NGC 1365, NGC 1566 and NGC 2997. We have also introduced a method of quantifying errors in the phase diagram used to detect CR. We established the m=2 pattern CR at 12.1 kpc, 9.4 kpc and 7 kpc, for NGC 1365, NGC 1566 and NGC 2997, respectively. By using published rotation c

John T. Stocke, J. Michael Shull, Steven V. Penton, Brad K. Gibson

Detecting HI using redshifted Ly-alpha absorption lines is 1e6 times more sensitive than using the 21cm emission line. We review recent discoveries of HI Ly-alpha absorbers made with the Hubble Space Telescope (HST) which have allowed us a first glimpse at gas in local intergalactic space between us and the ``Great Wall''. Despite its mere 2.4m apert

Lucia M. Franco

We present a comprehensive study of the properties of nearly coherent brightness oscillations (NCOs) in a large sample of type-I X-ray bursts observed from low mass X-ray binary 4U 1728-34. We have analyzed ~545ks of data of this source obtained with the Rossi X-ray Timing Explorer over a 3 year span from 1996-1999. The data contain 38 bursts, 16 of which sh

D. Markovic, F. K. Lamb

We investigate the suggestion that the frequencies of the kilohertz and other QPOs in the emission from neutron stars in low-mass X-ray binaries are generated by geodesic motion of gas clumps around the star. First we assume, following previous work, that the dominant frequencies produced by such motions are the azimuthal frequency \nuk, the apsidal precessi

Charles H. Nelson

The recent discovery of a correlation between nuclear black hole mass, M_bh, and the stellar velocity dispersion (Gebhardt et al. 2000, Ferrarese and Merritt 2000), in elliptical galaxies and spiral bulges, has raised the question whether such a relationship exists for AGN. Estimates of M_bh for many AGN, made using reverberation mapping techniques, allow ex

Yuri G. Zarhin

In his previous paper (Math. Res. Letters 7(2000), 123--132) the author proved that in characteristic zero the jacobian $J(C)$ of a hyperelliptic curve $C: y^2=f(x)$ has only trivial endomorphisms over an algebraic closure $K_a$ of the ground field $K$ if the Galois group $Gal(f)$ of the irreducible polynomial $f(x) \in K[x]$ is either the symmetric group $S

Benjamin D. G. Chandran

Observations of narrow radio-emitting filaments near the Galactic center have been interpreted in previous studies as evidence of a pervasive vertical (i.e. perpendicular to the Galactic plane) milliGauss magnetic field in the central 150 pc of the Galaxy. A simple cylindrically symmetric model for the equilibrium in this central region is proposed in which

A. Aradian, E. Raphael, P. -G. de Gennes

In many industrial processes, pieces of the same polymer material are brought into contact at a temperature above the glass transition. Interdiffusion then takes place across the interface and leads to a strengthening of the junction. Often, a crosslinker agent is also added in order to improve the global mechanical properties of the material, as in the form

Antonio Pineda, Antonio Vairo

Within an effective field theory framework, we obtain an expression, with O(1/m^2) accuracy, for the energies of the gluonic excitations between heavy quarks, which holds beyond perturbation theory. For the singlet heavy quark--antiquark energy, in particular, we also obtain an expression in terms of Wilson loops. This provides, twenty years after the semina

S. A. Abel, G. Servant

We show that the dilaton and T-moduli can be stabilized by a single gaugino condensation mechanism in the four-dimensional effective field theory derived from Type IIB orientifolds. A crucial role is played by the mixing of the blowing-up modes Mk with the T-moduli in the Kahler metric, and by the presence of the Mk in the gauge kinetic functions. Supersymme

Martin Gremm

We study four-dimensional U(1) on a non-commutative T^2 with rational Theta. This theory has dual descriptions as ordinary SYM or as NCOS. We identify a set of massive non-interacting KK states in the SYM theory and track them through the various dualities. They appear as stretched strings in the non-commutative U(1) providing another example of the IR/UV mi

A. C. Maggs

We study the geometry of a semiflexible polymer at finite temperatures. The writhe can be calculated from the properties of Gaussian random walks on the sphere. We calculate static and dynamic writhe correlation functions. The writhe of a polymer is analogous to geometric or Berry phases studied in optics and wave mechanics. Our results can be applied to con

A. B. Batista, J. C. Fabris, S. V. B. Goncalves

We exploit the possibility of existence of a repulsive gravity phase in the evolution of the Universe. A toy model with a free scalar field minimally coupled to gravity, but with the "wrong sign" for the energy and negative curvature for the spatial section, is studied in detail. The background solutions display a bouncing, non-singular Universe. The

H. Yokomakura, K. Kimura, A. Takamura

We study the matter enhancement of T violation in neutrino oscillation with three generations. The magnitude of T violation is proportional to Jarlskog factor J. Recently, the elegant relation, (Δ_m)_{12}(Δ_m)_{23}(Δ_m)_{31}J_{m} = Δ_{12}Δ_{23}Δ_{31}J, was derived, where Δ_{ij}=Δm^2_{ij}/(2E) and subscript m implies the quantities in matter. Using this relat

F. T. Brandt, Ashok Das, J. Frenkel

We study, to one loop order, the behavior of the gluon self-energy in the non covariant Coulomb gauge at finite temperature. The cancellation of the peculiar energy divergences, which arise in such a gauge, is explicitly verified in the complete two point function of the Yang-Mills theory. At high temperatures, the leading T^2 term is determined to be transv

P. Erwin, J. C. Vega Beltran, J. E. Beckman

NGC 4340 is a double-barred SB0 galaxy in the Virgo cluster (Wozniak et al. 1995). Here, we present evidence that this galaxy also posseses a luminous stellar nuclear ring of relatively old stars with little or no gas. The ring lies just outside the inner bar, at the probable inner inner Lindblad resonance (IILR) of the outer bar. Careful inspection of the i

M. Hassaïne, P. A. Horváthy

The symmetries of the general Euler equations of fluid dynamics with polytropic exponent are determined using the Kaluza-Klein type framework of Duval et $\it{al}$. In the standard polytropic case the recent results of O'Raifeartaigh and Sreedhar are confirmed and generalized. Similar results are proved for polytropic exponent $γ=-1$, which corresponds t

Annalisa Fierro, Antonio de Candia, Antonio Coniglio

In this paper we study the 3d frustrated lattice gas model in the annealed version, where the disorder is allowed to evolve in time with a suitable kinetic constraint. Although the model does not exhibit any thermodynamic transition it shows a diverging peak at some characteristic time in the dynamical non-linear susceptibility, similar to the results on the

Adan Cabello

Recently, Zhang, Li, and Guo have proposed a particular eavesdropping attack [Phys. Rev. A {\bf 63}, 036301 (2001), quant-ph/0009042] which shows that my quantum key distribution protocol based on entanglement swapping [Phys. Rev. A {\bf 61}, 052312 (2000), quant-ph/9911025] is insecure. However, security against this attack can be attained with a simple mod

Mircea Neagu

The author exposes the metrical multi-time Lagrange geometry of physical fields which naturally generalizes the classical Lagrangian developped by Miron and Anastasiei. In other words, one constructs a natural theory of physical fields on the 1-jet fibre bundle, attached to a Kronecker h-regular multi-time Lagrangian with partial derivatives of order one.

Neil F. Johnson

The quantum advantage arising in a simplified multi-player quantum game, is found to be a disadvantage when the game's qubit-source is corrupted by a noisy "demon". Above a critical value of the corruption-rate, or noise-level, the coherent quantum effects impede the players to such an extent that the optimal choice of game changes from quantum t

Alex Kovner

In these notes I explain the idea how one could understand confinement by studying the low energy effective dynamics of non Abelian gauge theories. I argue that under some mild assumptions, the low energy dynamics is determined universally by the spontaneous breaking of the magnetic symmetry introduced by 't Hooft more than 20 years ago. The degrees of f

Brett McInnes

The background geometries of the AdS/CFT and the Randall-Sundrum theories are locally similar, and there is strong evidence for some kind of "complementarity" between them; yet the global structures of the respective manifolds are very different. We show that this apparent problem can be understood in the context of a more complete global formulation

G. Date

A general analysis for characterizing and classifying `isolated horizons' is presented in terms of null tetrads and spin coefficients. The freely specifiable spin coefficients corresponding to isolated horizons are identified and specific symmetry classes are enumerated. For isolated horizons admitting at least one spatial isometry, a standard set of sph

Tohya Hiroshima

I investigate dense coding with a general mixed state on the Hilbert space $C^{d}\otimes C^{d}$ shared between a sender and receiver. The following result is proved. When the sender prepares the signal states by mutually orthogonal unitary transformations with equal {\it a priori} probabilities, the capacity of dense coding is maximized. It is also proved th

Madan Rao, Sarasij R C

We investigate the steady states and dynamical instabilities resulting from ``particles'' depositing on (fusion) and pinching off (fission) a fluid membrane. These particles could be either small lipid vesicles or isolated proteins. In the stable case, such fusion/fission events suppress long wavelength fluctuations of the membrane. In the unstable c

Arindam Mitra

A computationally secure noised based cipher system is proposed. The advantage of this cipher system is that it operates above noise level. Therefore computationally secure communication can be done when error correction code fails. Another feature of this system is that minimum number of exhaustive key search can be made fixed.

Bijoy K. Dey, Moshe Shapiro, Paul Brumer

Quantum interference effects are shown to provide a means of controlling and enhancing the focusing a collimated neutral molecular beam onto a surface. The nature of the aperiodic pattern formed can be altered by varying laser field characteristics and the system geometry.

Z. Brzezniak, Z. Haba

We consider second order differential operators with coefficients which are Gaussian random fields. When the covariance becomes singular at short distances then the propagators of the Schrödinger equation as well as of the wave equation behave in an anomalous way. In particular, the Feynman propagator for the wave equation is less singular than the one with

An Min Wang

The general expression with the physical significance and positive definite condition of the eigenvalues of $4\times 4$ Hermitian and trace-one matrix are obtained. This implies that the eigenvalue problem of the $4\times 4$ density matrix is generally solved. The obvious expression of Peres' separability condition for an arbitrary state of two qubits is

C. Castro, A. Granik

A new relativity theory, or more concretely an extended relativity theory, actively developed by one of the authors incorporated 3 basic concepts. They are the old idea of Chew about bootstrapping, Nottale's scale relativity, and enlargement of the conventional time-space by inclusion of noncommutative Clifford manifolds where all p-branes are treated on

S. I. Bityukov, N. V. Krasnikov, V. A. Taperechkina

The possibility of construction of continuous analogue of Poisson distribution with the search of bounds of confidence intervals for parameter of Poisson distribution is discussed. Also, in the article is shown that the true value of a parameter of Poisson distribution for the observed value $\hat x$ has Gamma distribution with the scale parameter, which is

Andres Aguado, Jose M. Lopez

The structures and relative stabilities of doubly-charged nonstoichiometric (CaO)$_n$Ca$^{2+}$ (n=1--29) cluster ions and of neutral stoichiometric (MgO)$_n$ and (CaO)$_n$ (n=3,6,9,12,15,18) clusters are studied through {\em ab initio} Perturbed Ion plus polarization calculations. The large coordination-dependent polarizabilities of oxide anions favor the fo

Carsten Greiner, Stefan Leupold

Recently it has been shown that the observed antiproton yield in heavy-ion collisions at CERN-SpS energies can be understood by multi-pionic interactions which enforce local chemical equilibrium of the antiprotons with the nucleons and pions. Here we show that antihyperons are driven towards local chemical equilibrium with pions, nucleons and kaons on a time

K. A. Bugaev, M. I. Gorenstein, W. Greiner

Discontinuities in relativistic hydrodynamics - shock waves and freeze-out shocks - are considered across both space-like and time-like hypersurfaces. We analyze the peculiar features of the freeze-out discontinuities and their connection to the shock-wave phenomena.

S. A. Fayans, D. Zawischa

The ground-state properties of superfluid nuclear systems with ^1S_0 pairing are studied within a local energy-density functional (LEDF) approach. A new form of the LEDF is proposed with a volume part which fits the Friedman- Pandharipande and Wiringa-Fiks-Fabrocini equation of state at low and moderate densities and allows an extrapolation to higher densiti

STAR Collaboration, K. H. Ackermann

Elliptic flow from nuclear collisions is a hadronic observable sensitive to the early stages of system evolution. We report first results on elliptic flow of charged particles at midrapidity in Au+Au collisions at sqrt(s_NN)=130 GeV using the STAR TPC at RHIC. The elliptic flow signal, v_2, averaged over transverse momentum, reaches values of about 6% for re

Cristobal Lopez, Emilio Hernandez-Garcia, Oreste Piro, Angelo Vulpiani

A discrete-time model of reacting evolving fields, transported by a bidimensional chaotic fluid flow, is studied. Our approach is based on the use of a Lagrangian scheme where {\it fluid particles} are advected by a $2d$ symplectic map possibly yielding Lagrangian chaos. Each {\it fluid particle} carries concentrations of active substances which evolve accor

Robert Conte, Micheline Musette

When subjected to a horizontal temperature difference, a fluid layer with a free surface becomes unstable and hydrothermal waves develop in the bulk. Such a system is modelized by two coupled amplitude equations of the one-dimensional, complex, cubic Ginzburg-Landau type. By transposing the method developed for one CGL3 equation, we obtain several new exact

Christopher G. Jesudason

By examining both the divergence of the velocity vector in orthogonal Cartesian coordinate space $\mathbfΓ $ of dimension $\R^{\textrm {2fN}}$ and the structure of the Hamiltonian determining a system trajectory, it is shown that the standard Liouville equation cannot describe anything more than linear motion for typical Hamiltonians with separated momentum

Gerd Rudolph, Matthias Schmidt, Igor P. Volobuev

The natural partial ordering of the orbit types of the action of the group of local gauge transformations on the space of connections in space-time dimension d<=4 is investigated. For that purpose, a description of orbit types in terms of cohomology elements of space-time, derived earlier, is used. It is shown that, on the level of these cohomology elements,

Gian Mario Besana, Sandra Di Rocco

Smooth complex surfaces polarized with an ample and globally generated line bundle of degree three and four, such that the adjoint bundle is not globally generated, are considered. Scrolls of a vector bundle over a smooth curve are shown to be the only examples in degree three. Two classes of examples in degree four are presented, one of which is shown to ch

A. B. Goncharov

We study the action of the Galois group on the pro-l-completion of the fundamental group of P^1 - {0, infinity and N-th roots of unity}. We describe the Lie algebra of the image of the Galois action and relate with the geometry of the modular varieties for GL_m for m = 1,2,3,... This story is the l-adic side of the motivic theory of multiple polylogarithms a

E. Brian Davies, Josef Leydold, Peter F. Stadler

We give a detailed proof for two discrete analogues of Courant&#39;s Nodal Domain Theorem.

Nicolas Andruskiewitsch, Hans-Jurgen Schneider

Since the discovery of quantum groups (Drinfeld, Jimbo) and finite dimensional variations thereof (Lusztig, Manin), these objects were studied from different points of view and had many applications. The present paper is part of a series where we intend to show that important classes of Hopf algebras are quantum groups and therefore belong to Lie theory. One

A. Abrams, R. Ghrist

This expository article describes applications of topological configuration spaces to the control of robotic systems. In particular, we review recent work by the authors on configuration spaces of graphs. These are lovely spaces: we show for example that the configuration space of two points on the complete graph of five vertices is a closed orientable surfa

Helmut Prodinger

For words of length n, generated by independent geometric random variables, we consider the average value and the average position of the r-th left-to-right maximum counted from the right, for fixed r and n->oo. This complements previous research where the analogous questions were considered for the r-th left-to-right maximum counted from the left.

Andrew Kresch

The class in the Brauer group of a quaternion algebra over a field is 2-torsion. We study the following question: Which 2-torsion elements of the Brauer group of a complex function field are representable by quaternion algebras? Using intersection theory to show that a certain cohomology class (on a smooth projective model) is the class of an algebraic cycle

Bjorn Birnir, Hoskuldur A. Hauksson

The notions of basic controllability and basic control are defined using dynamical systems theory of partial differential equations. A quadratic optimal control of the linearized viscous Moore-Greitzer equation is presented and it is confirmed that stall is uncontrollable in this model. A basic control is constructed for the nonlinear viscous Moore-Greitzer

Jozef Dodziuk, Varghese Mathai, Stuart Yates

It was pointed out to us that the proof of a crucial lemma (Lemma 5.3) in the paper is incorrect. Thus the approximation theorem (Theorem 0.1) for L^2 torsion of an amenable covering of a finite simplicial complex remains unproved. However, results and proofs of the first four sections (in particular, the approximation theorem (Theorem 0.3) for the spectral

Mikhail Grinberg

We develop the idea of self-indexing and the technology of gradient-like vector fields in the setting of Morse theory on a complex algebraic stratification. Our main result is the local existence, near a Morse critical point, of gradient-like vector fields satisfying certain ``stratified dimension bounds up to fuzz&#39;&#39; for the ascending and descending

Alex Lewis

The correspondences between logarithmic operators in the CFTs on the boundary of AdS_3 and on the world-sheet and dipole fields in the bulk are studied using the free field formulation of the SL(2,C)/SU(2) WZNW model. We find that logarithmic operators on the boundary are related to operators on the world-sheet which are in indecomposable representations of

Stephan Dürr

A summary is given of a quantization of the multiflavour Schwinger model on a finite-temperature cylinder with chirality-breaking boundary conditions at its spatial ends, and it is shown that the analytic expression for the chiral condensate implies that the theory exhibits a second order phase transition with $T_c = 0$.

Keiichi Akama

We show how the gravity, gauge, and matter fields are induced on dynamically localized brane world.

Ashoke Sen

It has been conjectured that condensation of tachyons on a bosonic D-brane gives rise to vacuum / soliton solutions which are independent of the initial magnetic field on the D-brane. We present evidence for this conjecture using results from two dimensional conformal field theory. In particular we identify a continuous path in the configuration space of ope

S. Q. Wu, X. Cai

The classical first law of thermodynamics for a Kerr-Newman black hole (KNBH) is generalized to a law in quantum form on the event horizon. Then four quantum conservation laws on the KNBH equilibrium radiation process are derived. The Bekenstein-Hawking relation ${\cal{S}}={\cal{A}}/4$ is exactly established. It can be inferred that the classical entropy of

James Baugh, David Ritz Finkelstein, Andrei Galiautdinov, Heinrich Saller

We suggest Clifford algebra as a useful simplifying language for present quantum dynamics. Clifford algebras arise from representations of the permutation groups as they arise from representations of the rotation groups. Aggregates using such representations for their permutations obey Clifford statistics. The vectors supporting the Clifford algebras of perm

Takao Suyama

We construct an effective action describing brane-antibrane system containing N D-branes and N \bar{D}-branes. BPS equations for remaining D-branes after tachyon condensation are derived and their properties are investigated. The value of the D-brane tension and the number of brane bound states are discussed.

J. Serreau

The dynamics of the pion field after a quench is studied in the framework of the linear sigma model. Our aim is to determine to what extent the amplified pion field resembles the DCC picture originally proposed in the early &#39;90s. We present the result of a computer experiment where, among other things, we study in detail the correlation between isospin o

Antonio Vairo

The potential between heavy quarks can be rigorously defined in a QCD effective field theories framework. I discuss the general situation when the coupling constant may not be considered small and provide an explicit expression for the potential valid up to order 1/m^2. Spin dependent and spin independent terms are expressed in terms of Wilson loops, complet

C. Greub, P. Liniger

A detailed standard model (SM) calculation of the O(alpha_s) virtual corrections to the decay width for b -> s g is presented (g denotes a gluon). Also the complete expressions for the corresponding bremsstrahlung corrections are given. Taking into account the existing next-to-leading logarithmic (NLL) result for the Wilson coefficient C_8^eff, a complete NL

Nora Brambilla

In the framework of the QCD effective field theory called potential Non-Relativistic QCD, we explore quark-antiquark bound systems that may be dominated by the perturbative interaction and we discuss the extent of validity of such a picture. Some phenomenological implications are outlined.

T. N. Pham

The large branching ratios for $B \to Kπ$ decays as observed by the CLEO Collaboration indicate that penguin interactions contribute a major part to the decay rates and provide an interference between the Cabibbo-suppressed tree and penguin contributions resulting in a CP-asymmetry between the $B \to Kπ$ and its charge conjugate mode. The CP-averaged decay r

G. Moreau

We study the single chargino production $e^+ e^- \to \tilde χ^{\pm} μ^{\mp}$ at linear colliders which occurs through the $ł_{121}$ R-parity violating coupling constant. We focus on the final state containing 4 leptons and some missing energy. The largest background is \susyq and can be reduced using the initial beam polarization and some cuts based on the s

Stephan Dürr

I give a sketch of my recent attempt to test the prediction by Leutwyler and Smilga according to which, for QCD in a finite box with $N_{f} \geq 2$, the combination $x = V Σm$ indicates whether the net topological charge of the gauge background proves relevant ($x \ll 1$) or irrelevant ($x \gg 1$) for physical observables.

E. A. Kuraev, L. N. Lipatov, T. V. Shishkina

We consider the radiative corrections to the impact factors of electron and photon. According to a generalized eikonal representation the e\bar e scattering amplitude at high energies and fixed momentum transfers is proportional to the electron form factor. But we show that this representation is violated due to the presence of non-planar diagrams. One loop

Benjamin Svetitsky, Alec Schramm

We propose using the Skyrme model on a lattice as an effective field theory of meson-baryon interactions. To this end we construct a local topological density that involves the volumes of tetrahedra in the target space S^3 and we make use of Coxeter&#39;s formula for the Schlafli function to implement it. We calculate the mean-square radius of a skyrmion in

Douglas R Bergman

We present a preliminary report on a new measurement of the radiative neutral Ke3 branching ratio and the first study of the photon spectrum in this decay. We find BR(Ke3g, E*_g>30 GeV, Th*_eg>20 deg)/BR(Ke3) = 0.911+-0.009(stat)+0.021-0.010(syst)%. Our measurement of the spectrum is consistent with inner bremsstrahlung only as the source of photons at the 2

M. P. Besuglov, B. M. Bobchenko, E. V. Byistritskaya, A. A. Vasenko

The total, elastic and inelastic cross-sections for quasi-coherent interactions of protons with Si28 have been measured using hadron-gamma coincidence method at the energy 1 GeV. The limits for the existence of long-lived excited states of the Si28 nucleus have been obtained in the range of energies from 0 to 0.8 GeV.

A. Alavi-Harati

We report on a search for the decay Kl -> pi0 e+ e- carried out by the KTeV/E799 experiment at Fermilab. This decay is expected to have a significant CP violating contribution and the measurement of its branching ratio could support the CKM mechanism for CP violation or could point to new physics. Two events were observed in the 1997 data with an expected ba

H. N. Brown

A new measurement of the positive muon&#39;s anomalous magnetic moment has been made at the Brookhaven Alternating Gradient Synchrotron using the direct injection of polarized muons into the superferric storage ring. The angular frequency difference omega_{a} between the angular spin precession frequency omega_{s} and the angular orbital frequency omega_{c}

Sergiu I. Vacaru, Heinz Dehnen

We analyze local anisotropies induced by anholonomic frames and associated nonlinear connections in general relativity and extensions to affine Poincare and de Sitter gauge gravity and different types of Kaluza-Klein theories. We construct some new classes of cosmological solutions of gravitational field equations describing Friedmann-Robertson-Walker like u

Heinz Dehnen, Sergiu I. Vacaru

We apply the method of moving anholonomic frames, with associated nonlinear connections, in (pseudo) Riemannian spaces and examine the conditions when various types of locally anisotropic (la) structures (Lagrange, Finsler like and more general ones) could be modeled in general relativity. New classes of solutions of the Einstein equations with generic local

Bernard Haisch, Alfonso Rueda, York Dobyns

Even when the Higgs particle is finally detected, it will continue to be a legitimate question to ask whether the inertia of matter as a reaction force opposing acceleration is an intrinsic or extrinsic property of matter. General relativity specifies which geodesic path a free particle will follow, but geometrodynamics has no mechanism for generating a reac

J. Zapata, A. M. Guzman, M. G. Moore, P. Meystre

We discuss the dynamics of ultracold atoms in an optical potential accelerated by gravity. The positions and widths of the Wannier-Stark ladder of resonances are obtained as metastable states. The metastable Wannier-Bloch states oscillate in a single band with the Bloch period. The width of the resonance gives the rate transition to the continuum.

Sung Yong Park, M. Y. Choi, Beom Jun Kim, Gun Sang Jeon

This study investigates in detail the finite-size scaling of the two-dimensional irrationally frustrated XY model. By means of Monte Carlo simulations with entropic sampling, we examine the size dependence of the specific heat, and find remarkable deviation from the conventional finite-size scaling theory, which reveals novel intrinsic finite-size effects. R

Gustavo R. Gonzalez-Martin

It is shown that if the carriers in the fractional quantum Hall effect are taken as geometrical excitations with quanta of charge e and magnetic flux h/2e, as proposed in a previous publication, the calculated results are compatible with the series of fractions obtained experimentally.

Oded Farago, Yacov Kantor

A new method is used to measure the stress and elastic constants of purely entropic phantom networks, in which a fraction $p$ of neighbors are tethered by inextensible bonds. We find that close to the percolation threshold $p_c$ the shear modulus behaves as $(p-p_c)^f$, where the exponent $f\approx 1.35$ in two dimensions, and $f\approx 1.95$ in three dimens

G. Caldarelli, R. Marchetti, L. Pietronero

In this paper we show that the Internet web, from a user&#39;s perspective, manifests robust scaling properties of the type $P(n)\propto n^{-τ}$ where n is the size of the basin connected to a given point, $P$ represents the density of probability of finding n points downhill and $τ=1.9 \pm 0.1$ s a characteristic universal exponent. This scale-free structur

M. Borromeo, F. Marchesoni

A driven Brownian particle (e.g. an adatom on a surface) diffusing on a low-viscosity, periodic substrate may execute multiple jumps. In the presence of an additional periodic drive, the jump lengths and time durations become statistically modulated according to a syncronyzation mechanism reminiscent of asymmetric stochastic resonance. Here, too, bistability

Pierre-Gilles de Gennes

We present a modified version of our &#34;sliding model&#34;, where chain arcs, between two contacts at the surface, may move if all the barriers along the arc are weaker than a certain threshold.An important advance of the revised model is that the high limiting chain lengths N* observed in the experiments are naturally accoundted for. In this model, a film

A. A. Aligia

We study the dependence of the magnetization M with magnetic field B at zero temperature in the spin-1/2 XXZ chain with nearest-neighbor (NN) J1 and next-NN J2 exchange interactions, with anisotropies Delta1 and Delta2 respectively. The region of parameters for which a jump in M(B) exists is studied using numerical diagonalization, and analytical results for

S. S. Manna

Internal avalanches of grain displacements can be created inside a granular material kept in a bin in two ways: (i) By removing a radomly selected grain at the bottom of the bin (ii) By breaking a stable arch of grains clogging a hole at the bottom of the bin. Repeated generations of such avalanches lead the system to a steady state. The question asked, is t

Eric Falcon, Stephan Fauve, Claude Laroche

We report experimental results on the behavior of an ensemble of inelastically colliding particles, excited by a vibrated piston in a vertical cylinder. When the particle number is increased, we observe a transition from a regime where the particles have erratic motions (granular &#34;gas&#34;) to a collective behavior where all the particles bounce like a n

M. Krueger, M. R. Buitelaar, T. Nussbaumer, C. Schoenenberger

We explore the electric-field effect of carbon nanotubes (NTs) in electrolytes. Due to the large gate capacitance, Fermi energy shifts of order +/- 1 V can be induced, enabling to tune NTs from p to n-type. Consequently, large resistance changes are measured. At zero gate voltage the NTs are hole doped in air with E_F ? 0.3-0.5 eV, corresponding to a doping

F. Mazzanti, A. Polls

A detailed calculation of the finite temperature dynamic structure function of the free Bose gas is presented and discussed. After a short derivation of the expressions describing the exact response $S(q,ω;T)$ and the Impulse Approximation (IA) $S_{IA}(q,ω;t)$, their main properties and their evolution with q and T are analyzed. The lowest order energy weigh

Wolfgang Thimm, Christian Friedrich, Tobias Roths, Stefan Trinkle

This is the last part of a series of five articles published in Journal of Rheology (Maier et al. (1998), Thimm et al. (1999a), Thimm et al. (2000a), Thimm et al. (2000c)) in which progress on the determination of binary molecular weight distributions from rheological data has been reported. In this article is discussed in how far the developed methods can a

F. Corberi, G. Gonnella, A. Lamura

The phase-separation kinetics of binary fluids in shear flow is studied numerically in the framework of the continuum convection-diffusion equation based on a Ginzburg-Landau free energy. Simulations are carried out for different temperatures both in d=2 and in d=3. Our results confirm the qualitative picture put forward by the large-N limit equations studie

Robert M. Konik, Hubert Saleur, Andreas W. W. Ludwig

Symmetry restoration is usually understood as a renormalization group induced phenomenon. In this context, the issue of whether one-loop RG equations can be trusted in predicting symmetry restoration has recently been the subject of much debate. Here we advocate a more pragmatic point of view and expand the definition of symmetry restoration to encompass all