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March 2001 arXiv papers — page 3

Showing 201–300 of 2,717 papers

  1. Sergey M. Sikach

    The pattern of calculation of amplitudes of a series of processes in the field of an intensive laser wave, in which two fermions $(p; p')$ and two real photons $(k_1; k_2)$ participate, is considered. In relation to one-photon processes, these processes are of the second order on $α$, if the wave intensity $ξ\ll 1$ (i.e., actually absorption from the wav

  2. Alakabha Datta, C. S. Kim, David London

    We show that, unlike other pure b -> d penguin processes, the decay Bs(t) -> phi K_s is dominated by a single amplitude, that of the internal t-quark. The contributions of the u- and c-quark operators each vanish due to a cancellation between the (V-A) \otimes (V-A) and (V-A) \otimes (V+A) matrix elements. Thus, the indirect CP asymmetry in this decay probes

  3. C. S. Kim, Sechul Oh

    We propose a new method to extract the CP violating weak phase $γ$ in the CKM paradigm of the Standard Model, using $B^- \to D^0 π^- \to f π^-$ and $B^- \to \bar D^0 π^- \to f π^-$ decays, where $f$ are final states such as $K^+ π^-$, $K^+ ρ^-$, $K ππ$, {\it etc.} We also study the experimental feasibility of our new method. With possibility of new phases in

  4. Marcello Ciafaloni, Paolo Ciafaloni, Denis Comelli

    Electroweak radiative corrections with double-log enhancements occur in inclusive observables at the TeV scale because of a lack of compensation of virtual corrections with real emission due to the nonabelian (weak isospin) charges of the accelerator beams. Here we evaluate such Bloch-Nordsieck violating corrections in the case of initial longitudinal bosons

  5. Marcello Ciafaloni, Paolo Ciafaloni, Denis Comelli

    We point out that, in a spontaneously broken U(1) gauge theory, inclusive processes, whose primary particles are mass eigenstates that do not coincide with the gauge eigenstates, are not free of infrared logarithms. The charge mixing allowed by symmetry breaking and the ensuing Bloch-Nordsieck violation are here analyzed in a few relevant cases and in partic

  6. Frithjof Karsch

    We review recent results on QCD at finite temperature. Main emphasis is put on a discussion of observables which are of immediate interest to experimental searches for the Quark Gluon Plasma, i.e. the phase transition temperature, the equation of state in 2 and 3-flavour QCD, the heavy quark free energy and thermal effects on hadron masses.

  7. S. Groote, A. A. Pivovarov

    We calculate the low-energy limit of heavy quark current correlators within an expansion in the inverse heavy quark mass. The induced low-energy currents built from the gluon fields corresponding to the initial heavy quark currents are obtained from an effective action for gauge fields in the one-loop approximation at the leading order of the 1/m expansion.

  8. J. Maalampi, V. Sipilainen, I. Vilja

    We study neutrino physics in a model with one large extra dimension. We assume the existence of two four-dimensional branes in the five-dimensional space-time, one for the ordinary particles and the other one for mirror particles, and we investigate neutrino masses and mixings in this scheme. Comparison of experimental neutrino data with the predictions of t

  9. M. Hindmarsh, A. Rajantie

    We present a detailed numerical study of the equilibrium and non-equilibrium dynamics of the phase transition in the finite-temperature Abelian Higgs model. Our simulations use classical equations of motion both with and without hard-thermal-loop corrections, which take into account the leading quantum effects. From the equilibrium real-time correlators, we

  10. M. A. Diaz, D. A. Ross

    We present the contributions from all types of one-loop corrections to the scattering amplitude for the pair production of polarized charginos or neutralinos from polarized electron-positron annihilation. The contributions are classified in terms of ``prototypes'' distinguished by the number of particles inside the loops and their spins. The results

  11. Rodolfo A. Diaz, R. Martinez, J-Alexis Rodriguez

    We consider the branching ratio for the process $t \to c γ$ in the context of the General Two Higgs Doublet Model type III. We find that taking into account reasonable values for the parameter $\tan β$ is possible to get values of this branching ratio up to orders of magnitude lying in the range of sensitivity of near future top quark experiments. For values

  12. A. Bashir, A. Raya

    We derive perturbative constraints on the transverse part of the fermion-boson vertex in massive QED3 through its one loop evaluation in an arbitrary covariant gauge. Written in a particular form, these constraints naturally lead us to the first non-perturbative construction of the vertex, which is in complete agreement with its one loop expansion in all mom

  13. Hsiang-nan Li

    I review important aspects of the perturbative QCD approach to exclusive $B$ meson decays, concentrating on factorization theorem, gauge invariance, end-point singularities, $k_T$ and threshold resummations, power counting, penguin enhancement, and CP asymmetries.

  14. O. V. Utyuzh, G. Wilk, Z. Wlodarczyk

    We propose new algorithm for numerical modelling of Bose-Einstein correlations (BEC). It is based on the fact that identical particles subjected to BEC do, by definition, bunch themselves in a maximal possible way, restricted only by conservation laws, in the same cells in phase-space.

  15. Edwin Laermann, Peter Schmidt

    We report on a lattice investigation of improved quenched Wilson fermions above and below the confinement-deconfinement phase transition. Results on meson screening masses as well as spatial wave functions are presented. Moreover, the meson dispersion relation is studied. Below the critical temperature we do not observe any significant temperature effect whi

  16. Guy D. Moore, Kari Rummukainen, Anders Tranberg

    At first order phase transitions the transition proceeds through droplet nucleation and growth. We discuss a lattice method for calculating the droplet nucleation rate, including the complete dynamical factors. The method is especially suitable for very strongly suppressed droplet nucleation, which is often the case in physically interesting transitions. We

  17. The NOMAD Collaboration, P. Astier

    We present a measurement of the polarization of Antilambda hyperons produced in nu_mu charged current interactions. The full data sample from the NOMAD experiment has been analyzed using the same V0 identification procedure and analysis method reported in a previous paper for the case of Lambda hyperons. The Antilambda polarization has been measured for the

  18. Juergen Schmidt, Christopher Kohler

    Using the notion of a general conical defect, the Regge Calculus is generalized by allowing for dislocations on the simplicial lattice in addition to the usual disclinations. Since disclinations and dislocations correspond to curvature and torsion singularities, respectively, the method we propose provides a natural way of discretizing gravitational theories

  19. I. Radinschi

    We show that using an adequate coordinate transformation the charged regular black hole solution given by Ayon-Beato and Garcia can be put in the Kerr-Schild form. Then we use this metric in Kerr-Schild Cartesian coordinates with a result given by Virbhadra and obtain the energy distribution associated with this.

  20. Nina Jansen, Peter Diener, Alexei Khokhlov, Igor Novikov

    We study physical properties of conformal initial value data for single and binary black hole configurations obtained using conformal-imaging and conformal-puncture methods. We investigate how the total mass M_tot of a dataset with two black holes depends on the configuration of linear or angular momentum and separation of the holes. The asymptotic behavior

  21. H. Nikolic

    It is argued that the Rindler quantization is not a correct approach to study the effects of acceleration on quantum fields. First, the "particle"-detector approach based on the Minkowski quantization is not equivalent to the approach based on the Rindler quantization. Second, the event horizon, which plays the essential role in the Rindler quantizat

  22. Hans Ringstrom

    Bianchi VIII vacuum solutions to Einstein's equations are causally geodesically complete to the future, given an appropriate time orientation, and the objective of this article is to analyze the asymptotic behaviour of solutions in this time direction. For the Bianchi class A spacetimes, there is a formulation of the field equations that was presented in

  23. Lawrence C. Paulson

    This book chapter establishes connections between the interactive proof tool Isabelle and classical tableau and resolution technology. Isabelle's classical reasoner is described and demonstrated by an extended case study: the Church-Rosser theorem for combinators. Compared with other interactive theorem provers, Isabelle's classical reasoner achieves

  24. Lawrence C. Paulson, Krzysztof Grabczewski

    Fairly deep results of Zermelo-Frenkel (ZF) set theory have been mechanized using the proof assistant Isabelle. The results concern cardinal arithmetic and the Axiom of Choice (AC). A key result about cardinal multiplication is K*K = K, where K is any infinite cardinal. Proving this result required developing theories of orders, order-isomorphisms, order typ

  25. Lawrence C. Paulson

    A special final coalgebra theorem, in the style of Aczel's, is proved within standard Zermelo-Fraenkel set theory. Aczel's Anti-Foundation Axiom is replaced by a variant definition of function that admits non-well-founded constructions. Variant ordered pairs and tuples, of possibly infinite length, are special cases of variant functions. Analogues of

  26. Lawrence C. Paulson

    A step-by-step presentation of the code for a small theorem prover introduces theorem-proving techniques. The programming language used is Standard ML. The prover operates on a sequent calculus formulation of first-order logic, which is briefly explained. The implementation of unification and logical inference is shown. The prover is demonstrated on several

  27. Lawrence C. Paulson, Andrew W. Smith

    An attempt at unifying logic and functional programming is reported. As a starting point, we take the view that "logic programs" are not about logic but constitute inductive definitions of sets and relations. A skeletal language design based on these considerations is sketched and a prototype implementation discussed.

  28. Lawrence C. Paulson

    Many automatic theorem-provers rely on rewriting. Using theorems as rewrite rules helps to simplify the subgoals that arise during a proof. LCF is an interactive theorem-prover intended for reasoning about computation. Its implementation of rewriting is presented in detail. LCF provides a family of rewriting functions, and operators to combine them. A succes

  29. Ted Pedersen

    This paper presents a corpus-based approach to word sense disambiguation where a decision tree assigns a sense to an ambiguous word based on the bigrams that occur nearby. This approach is evaluated using the sense-tagged corpora from the 1998 SENSEVAL word sense disambiguation exercise. It is more accurate than the average results reported for 30 of 36 word

  30. Ian Foster, Carl Kesselman, Steven Tuecke

    "Grid" computing has emerged as an important new field, distinguished from conventional distributed computing by its focus on large-scale resource sharing, innovative applications, and, in some cases, high-performance orientation. In this article, we define this new field. First, we review the "Grid problem," which we define as flexible, secu

  31. Naoki Katoh, Takeshi Tokuyama

    We give an algorithm to compute all the local peaks in the $k$-level of an arrangement of $n$ lines in $O(n \log n) + \tilde{O}((kn)^{2/3})$ time. We can also find $τ$ largest peaks in $O(n \log ^2 n) + \tilde{O}((τn)^{2/3})$ time. Moreover, we consider the longest edge in a parametric minimum spanning tree (in other words, a bottleneck edge for connectivity

  32. Jonah Erlebacher, Michael J. Aziz, Alain Karma, Nikolay Dimitrov

    Dealloying is a common corrosion process during which an alloy is "parted" by the selective dissolution of the electrochemically more active elements. This process results in the formation of a nanoporous sponge composed almost entirely of the more noble alloy constituents . Even though this morphology evolution problem has attracted considerable att

  33. Ramin Golestanian, Elie Raphael

    The dynamics of the deformations of a moving contact line is studied assuming two different dissipation mechanisms. It is shown that the characteristic relaxation time for a deformation of wavelength $2π/|k|$ of a contact line moving with velocity $v$ is given as $τ^{-1}(k)=c(v) |k|$. The velocity dependence of $c(v)$ is shown to drastically depend on the di

  34. J. Vidal, P. Butaud, B. Doucot, R. Mosseri

    We study the effect of disorder and interactions on a recently proposed magnetic field induced localization mechanism. We show that both partially destroy the extreme confinement of the excitations occuring in the pure case and give rise to unusual behavior. We also point out the role of the edge states that allows for a propagation of the electrons in these

  35. M. Mercedes Calbi, Milton W. Cole, Silvina M. Gatica, Mary J. Bojan

    An overview is presented of the various phases predicted to occur when gases are absorbed within a bundle of carbon nanotubes. The behavior may be characterized by an effective dimensionality, which depends on the species and the temperature. Small molecules are strongly attracted to the interstitial channels between tubes. There, they undergo transitions be

  36. S. Drozdz, F. Gruemmer, F. Ruf, J. Speth

    Financial empirical correlation matrices of all the companies which both, the Deutsche Aktienindex (DAX) and the Dow Jones comprised during the time period 1990-1999 are studied using a time window of a limited, either 30 or 60, number of trading days. This allows a clear identification of the resulting correlations. On both these markets the decreases turn

  37. Ronald Blaak, Jose A. Cuesta

    In a previous paper (J. Zhang {\it et al.}, J. Chem. Phys. {\bf 110}, 5318 (1999)) we introduced a model for polydisperse hard sphere mixtures that is able to adjust its particle-size distribution. Here we give the explanation of the questions that arose in the previous description and present a consistent theory of the phase transition in this system, based

  38. Keshav N. Shrivastava

    The angular momentum model which couples the spin and charge is discussed as a possible theory of the quantum Hall effect. The high Landau level filling fractions 5/2, 7/3 and 8/3 are understood by this model. It is found that 7/3 and 8/3 are the particle-hole conjugates and 5/2 arises due to a limiting level at 1/2 with Landau level number n=5 which makes t

  39. F. Minardi, C. Fort, P. Maddaloni, M. Modugno

    We have performed time-domain interferometry experiments with matter waves trapped in an harmonic potential above and below the Bose-Einstein phase transition. We interrogate the atoms according to the method of separated oscillating fields, with a sequence of two radio-frequency pulses, separated by a time delay T. We observe the oscillation of the populati

  40. C. Alba-Simionesco, A. Toelle, D. Morineau, B. Farago

    The density correlation function F(q,t) of the two similar substituted aromatic liquids, Toluene and m-Toluidine, is studied by coherent neutron spin-echo and time-of-flight scattering for wave vectors q around the maximum q_max of the total static structure factor S_m(q) in the supercooled i.e. high density state far away from the normal fluid state. The wa

  41. Nicholas Robins, Craig Savage, Elena A. Ostrovskaya

    An ideal atom laser would produce an atomic beam with highly stable flux and energy. In practice the stability is likely to be limited by technical noise and nonlinear dynamical effects. We investigate the dynamics of an atom laser using a comprehensive one dimensional, mean-field numerical model. We fully model the output beam and experimentally important p

  42. P Sunthar, V Kumaran

    A new type of two phase coexistence in a vibrated granular material is reported, in the limit where energy transfer between the particles and the bottom wall occurs due to discrete collisions. A horizontally homogeneous bed develops inhomogeneities in which a dense and a dilute phase separate and coexist. The dilute region resembles a gas, while the dense re

  43. M. Pustilnik, L. I. Glazman

    We study peculiarities of transport through a Coulomb blockade system tuned to the vicinity of the spin transition in its ground state. Such transitions can be induced in practice by application of a magnetic field. Tunneling of electrons between the dot and leads mixes the states belonging to the ground state manifold of the dot. Remarkably, both the orbita

  44. Klaus Fabricius, Barry M. McCoy

    In a previous paper we demonstrated that Bethe's equations are not sufficient to specify the eigenvectors of the XXZ model at roots of unity for states where the Hamiltonian has degenerate eigenvalues. We here find the equations which will complete the specification of the eigenvectors in these degenerate cases and present evidence that the $sl_2$ loop a

  45. Matias Gomez, Tom Richtler, Leopoldo Infante, Georg Drenkhahn

    We have studied the Globular Cluster System of the merger galaxy NGC 1316 in Fornax, using CCD BVI photometry. A clear bimodality is not detected from the broadband colours. However, dividing the sample into red (presumably metal- rich) and blue (metal-poor) subpopulations at B-I=1.75, we find that they follow strikingly different angular distributions. The

  46. Christian Hettlage, Karl Mannheim

    We constrain high-energy neutrino fluxes with the observed cosmic ray and gamma ray fluxes, include flavor oscillations and propagation through Earth, and show that blazars could possibly be detected by cubic-kilometer neutrino telescopes.

  47. Ennio Poretti

    The OGLE database is revisited to investigate in more detail the properties of the Fourier parameters. Methodological improvements led us to identify a clear separation among High-Amplitude Delta Scuti (HADS), RRc and RRab stars. The bimodal distribution of the R21 parameter in HADS stars is explained as a contamination effect from RRc stars: there is eviden

  48. G. Bono, W. P. Gieren, M. Marconi, P. Fouque'

    We present new theoretical Period-Radius (PR) relations for first overtone Galactic Cepheids. Current predictions are based on several sequences of nonlinear, convective pulsation models at solar chemical composition (Y=0.28, Z=0.02) and stellar masses ranging from 3.0 to 5.5 Mo. The comparison between predicted and empirical radii of four short-period Galac

  49. Joanna Mikolajewska

    Symbiotic stars are long-period interacting binary systems in which an evolved red giant star transfers material to its much hotter compact companion. Such a composition places them among the most variable stars. In addition to periodic variations due to the binary motion they often show irregular changes due to nova-like eruptions of the hot component. In s

  50. J. Mikolajewska, E. Brandi, L. G. Garcia, O. Ferrer

    The symbiotic Mira, RX Pup, shows long-term variations in its mean light level due to variable obscuration by circumstellar dust. The last increase in extinction towards the Mira, between 1995 and 2000, has been accompanied by large changes in the degree of polarization in the optical and red spectral range. The lack of any obvious associated changes in the

  51. Aurelien Barrau, AMS collaboration

    The expected physics and astrophysics capabilities of the AMS experiment on board the International Space Station are briefly reviewed : high statistics study of cosmic rays in a wide range of energies, search for primordial antimatter, search for non-baryonic dark matter and, to some extent, gamma-ray astronomy.

  52. G. Paesold, A. O. Benz, K. -L. Klein, N. Vilmer

    The spatial association of narrow band metric radio spikes with type III bursts is analyzed. The analysis addresses the question of a possible causal relation between the spike emission and the acceleration of the energetic electrons causing the type III burst. The spikes are identified by the Phoenix-2 spectrometer (ETH Zurich) from survey solar observation

  53. A. E. Piatti, J. F. C. Santos, J. J. Claria, E. Bica

    Colour-magnitude diagrams are presented for the first time for L32, L38, K28 (L43), K44 (L68) and L116, which are clusters projected onto the outer parts of the Small Magellanic Cloud (SMC). The photometry was carried out in the Washington system $C$ and $T_1$ filters allowing the determination of ages by means of the magnitude difference between the red gia

  54. E. Moertsell, A. Goobar, L. Bergstrom

    We investigate the possibility to determine the fraction of compact objects in the Universe by studying gravitational lensing effects on Type Ia supernova observations. Using simulated data sets from one year of operation of the proposed dedicated supernova detection satellite SNAP, we find that it should be possible to determine the fraction of compact obje

  55. Bifang Liu, Emmi Meyer-Hofmeister

    The concept of an advection-dominated accretion flow (ADAF), with or without wind loss, was used to describe the spectra of the galactic center source Sgr A*, low-luminosity AGN and nuclei of elliptical galaxies (including M87). The spectral fits of various authors show that the transition from the geometrically thin disk to the hot flow occurs at quite diff

  56. P. Kahabka, K. S. de Boer, C. Bruens

    We analyzed a sample of 26 background X-ray sources in a ~60 square degree field of the Large Magellanic Cloud observed with the ROSAT PSPC. The sample has been selected from previously classified and optically identified X-ray sources. In addition pointlike and spectrally hard sources with at least 100 to 200 observed counts have been used for the analysis.

  57. Shujuan Wang, Yihua Yan, Qijun Fu

    An extended radio emission after a soft X-ray (SXR) maximum was detected in the active region NOAA 9077 by several observatories for the solar flare after 21:42 UT on July 10, 2000. Also some radio fine structures before the enduring radio emission were observed with the 1.0-2.0 GHz spectrometer of Beijing Astronomical Observatory (BAO) in the same time. We

  58. J. Ma, C. G. Shu

    In this paper, we investigate the star formation and chemical evolution of damped Lyman-$α$ systems (DLAs) based on the disc galaxy formation model which is developed by Mo, Mao & White. We propose that the DLAs are the central galaxies of less massive dark haloes present at redshifts $z\sim 3$, and they should inhabit haloes of moderately low circular veloc

  59. David J. Helfand, Edward C. Moran

    We present an empirical analysis of the integrated X-ray luminosity arising from populations of OB stars. In particular, we utilize results from the All-Sky Monitor on RXTE, along with archival data from previous missions, to assess the mean integrated output of X-rays in the 2-10 keV band from accreting early-type binaries within 3 kpc of the Sun. Using a r

  60. Hector G. Arce, Alyssa A. Goodman

    While observational evidence for the episodic nature of young stellar outflows continues to mount, existing numerical and theoretical models of molecular outflows assume they are formed by the interaction of a non-episodic wind from a young stellar object with an ambient cloud. In this Letter we estimate and discuss the effects of episodicity on the mass-vel

  61. S. Ehlerova, J. Palous

    We discuss the induced star formation in dense walls of expanding shells. The fragmentation process is studied using the linear perturbation theory. The influence of the energy input, the ISM distribution and the ISM speed of sound is examined analytically and by numerical simulations. We formulate the universal condition for the gravitational fragmentation

  62. S. B. Giddings, M. Lippert

    We revisit the problem of precursors in the AdS/CFT correspondence. Identification of the precursors is expected to improve our understanding of the tension between holography and bulk locality and of the resolution of the black hole information paradox. Previous arguments that the precursors are large, undecorated Wilson loops are found to be flawed. We arg

  63. Dorje C. Brody, Lane P. Hughston, Matthew F. Parry

    Starting from the canonical ensemble over the space of pure quantum states, we obtain an integral representation for the partition function. This is used to calculate the magnetisation of a system of N spin-1/2 particles. The results suggest the existence of a new type of first order phase transition that occurs at zero temperature in the absence of spin-spi

  64. Y. Bergner, R. Jackiw

    Following the construction of a model for the planar supersymmetric Chaplygin gas, supersymmetric fluid mechanics in (1+1)-dimensions is obtained from the light-cone parametrized Nambu-Goto superstring in (2+1)-dimensions. The lineal model is completely integrable and can be formulated neatly using Riemann coordinates. Infinite towers of conserved charges an

  65. C. King

    Additivity of the Holevo capacity is proved for product channels, under the condition that one of the channels is in a certain class of unital qubit channels, with the other completely arbitrary. This qubit class includes the depolarizing channel. As a byproduct this proves that the Holevo bound is the ultimate information capacity of such qubit channels (as

  66. M. Takada-Hidai, Y. Takeda, S. Sato, S. Honda

    LTE and NLTE abundances of sulfur in 6 metal-poor giants and 61 dwarfs (62 dwarfs, including the Sun) were explored in the range of -3 \lsim [Fe/H] \lsim $+0.5$ using high-resolution, high signal-to-noise ratio spectra of the \SI 8693.9 Åand 8694.6 Ålines observed by us and measured by \Francois (1987, 1988) and Clegg et al. (1981). NLTE effects in S abundan

  67. H. Y. Zhai, H. M. Christen, L. Zhang, C. Cantoni

    Superconducting magnesium diboride films with Tc0 ~ 24 K and sharp transition \~ 1 K were successfully prepared on silicon substrates by pulsed laser deposition from a stoichiometric MgB2 target. Contrary to previous reports, anneals at 630 degree and a background of 2x10^(-4) torr Ar/4%H2 were performed without the requirement of Mg vapor or an Mg cap layer

  68. A. Kashlinsky, C. Hernández--Monteagudo, F. Atrio--Barandela

    We present a new method for time-efficient and accurate extraction of the power spectrum from future cosmic microwave background (CMB) maps based on properties of peaks and troughs of the Gaussian CMB sky. We construct a statistic describing their angular clustering - analogously to galaxies, the 2-point angular correlation function, $ξ_ν(θ)$. We show that f

  69. Jennie Traschen, Daniel Fox

    We consider black-brane spacetimes that have at least one spatial translation Killing field that is tangent to the brane. A new parameter, the tension of a spacetime, is defined. The tension parameter is associated with spatial translations in much the same way that the ADM mass is associated with the time translation Killing field. In this work, we explore

  70. S. Alexandrov, D. Vassilevich

    We use the manifestly Lorentz covariant canonical formalism to evaluate eigenvalues of the area operator acting on Wilson lines. To this end we modify the standard definition of the loop states to make it applicable to the present case of non-commutative connections. The area operator is diagonalized by using the usual shift ambiguity in definition of the co

  71. Sven Bergmann, Gilad Perez

    We study extensions of the Standard Model where the charged current weak interactions are governed by the CKM matrix and where all tree-level decays are dominated by their Standard Model contribution. We constrain both analytically and numerically the ratio and the phase difference between the New Physics and the Standard Model contributions to the mixing am

  72. B. L. Ziegler, R. G. Bower, I. Smail, R. L. Davies

    (Abridged) We present morphological, photometric, kinematic and line-strength data of 48 early-type members of the rich cluster Abell 2218 at z=0.18. This sample is both larger and spans a wider galaxy luminosity range, down to M*_B+1, than previous studies. We compare A2218 with similar samples drawn from local clusters to identify evolutionary changes betw

  73. L. Derome, M. Buenerd, Yong Liu

    The secondary e+ and e- populations in near earth's orbit have been calculated by simulation. The results are in very good agreement with the recent AMS measurements. The e$^+$ over e$^-$ flux ratio for particles below the geomagnetic cutoff appears to be due to the geomagnetic East-West effect.

  74. D. Bolle', P. Kozlowski

    We show that for a particular choice of the coupling parameters the Ashkin-Teller spin-glass neural network model with the Hebb learning rule and one condensed pattern yields the same thermodynamic properties as the four-state anisotropic Potts-glass neural network model. This equivalence is not seen at the level of the Hamiltonians.

  75. Boris Mergell, Ralf Everaers

    In the first part of the paper we show that the constraining potentials introduced to mimic entanglement effects in Edwards' tube model and Flory's constrained junction model are diagonal in the generalized Rouse modes of the corresponding phantom network. As a consequence, both models can formally be solved exactly for arbitrary connectivity using t

  76. Andrea Cappelli, Riccardo Guida, Nicodemo Magnoli

    The general form of the stress-tensor three-point function in four dimensions is obtained by solving the Ward identities for the diffeomorphism and Weyl symmetries. Several properties of this correlator are discussed, such as the renormalization and scheme independence and the analogies with the anomalous chiral triangle. At the critical point, the coefficie

  77. D. V. Soroka, V. A. Soroka, J. Wess

    A supersymmetric $D = 1, N =1$ model with a Grassmann-odd Lagrangian is proposed which, in contrast to the model with an even Lagrangian, contains not only a kinetic term but also an interaction term for the coordinates entering into one real scalar Grassmann-even (bosonic) superfield.

  78. Victor Chernyak

    The cross section of hard diffractive dissociation of the pion into two jets is calculated. It is obtained that the distribution of longitudinal momenta for jets is not simply proportional to the profile of the pion wave function, but depends on it in a complicated way. In particular, it is shown that, under the conditions of the E791 experiment, the momentu

  79. E. Papantonopoulos, I. Pappa

    Motivated by brane cosmology we solve the Einstein equations with a time dependent cosmological constant. Assuming that at an early epoch the vacuum energy scales as $1/logt $, we show that the universe passes from a fast growing phase (inflation) to an expanding phase in a natural way.

  80. S. Y. Choi, Kaoru Hagiwara, Jae Sik Lee

    We re-evaluate the decays of the Higgs bosons in the minimal supersymmetric standard model (MSSM) where the tree-level CP invariance of the Higgs potential is explicitly broken by the loop effects of the third-generation squarks with CP-violating soft-breaking Yukawa interactions. This study is based on the mass matrix of the neutral Higgs bosons that is val

  81. A. A. Husainov, A. Pancar, M. Yapici

    The work is devoted to the extension groups in the category of functors from a small category to an additive category with an Abelian structure in the sense of Heller. It is constructed a spectral sequence which converges to the extension group. Example for diagrams of locally convex spaces is given.

  82. E. Bergshoeff, R. Kallosh, T. Ortin, D. Roest

    We discuss a generalized form of IIA/IIB supergravity depending on all R-R potentials C^(p) (p=0,1,...,9) as the effective field theory of Type IIA/IIB superstring theory. For the IIA case we explicitly break this R-R democracy to either p<=3 or p>=5 which allows us to write a new bulk action that can be coupled to N=1 supersymmetric brane actions. The case

  83. Christian Mercat, Paul A. Pearce

    We study integrable and conformal boundary conditions for ^sl(2) Z_k parafermions on a cylinder. These conformal field theories are realized as the continuum scaling limit of critical A-D-E lattice models with negative spectral parameter. The conformal boundary conditions labelled by (a,m) in (G, Z_{2k}) are identified with associated integrable lattice boun

  84. H. Barnum, N. Linden

    We introduce new entanglement monotones which generalize, to the case of many parties, those which give rise to the majorization-based partial ordering of bipartite states&#39; entanglement. We give some examples of restrictions they impose on deterministic and probabilistic conversion between multipartite states via local actions and classical communication

  85. Guy Bonneau, Jacques Faraut, Galliano Valent

    For the example of the infinitely deep well potential, we point out some paradoxes which are solved by a careful analysis of what is a truly self-adjoint operator. We then describe the self-adjoint extensions and their spectra for the momentum and the Hamiltonian operators in different physical situations. Some consequences are worked out, which could lead t

  86. M. Castagnino, R. Laura, R. Id Betan

    A quantum system with discrete and continuos evolution spectrum is studied. A final pointer basis is found, that can be defined in a presised mathematical way. This result is use to explain the quantum measurement in the system.

  87. W. A. Hofer

    Conventionally, one interprets the correlations observed in Einstein-Podolsky-Rosen experiments by Bell&#39;s inequalities and quantum nonlocality. We show, in this paper, that identical correlations arise, if the phase relations of electromagnetic fields are considered. In particular, we proceed from an analysis of a one-photon model. The correlation probab

  88. S. M. Bilenky

    The general status of neutrino physics are given. The history of the neutrino, starting from Pauli and Fermi, is presented. The phenomenological V-A theory of the weak interaction and the unified theory of the weak and electromagnetic interactions, the so-called Standard Model, are discussed. The problems of of neutrino masses, neutrino mixing, and neutrino

  89. S. Besio, A. Mazzino, C. F. Ratto

    It is well known that in a neutrally-stratified turbulent flow in a deep constant-stress layer above a flat surface, the variation of the mean velocity with respect to the distance from the surface obeys the logarithmic law (the so-called ``law-of-the-wall&#39;&#39;). More recently, the same logarithmic law has been found also in the presence of non flat sur

  90. A. M. Chechelnitsky

    Wave Universe Concept (WU Concept) opens new wide possibilities for the effective description of Elementar Objects of Matter (EOM) hierarchy, in particular, of particles, resonances mass spectrum of subatomic (and HEP) physics. The special attention to analysis and precise description of wide and important set - Transitive states (resonances) of EOM is payed

  91. David Bower, Sean Gavin

    Baryon fluctuations exceeding Poisson expectations can signal a nearly first order phase transition at RHIC. We show how these fluctuations can be measured, and apply a dissipative-hydrodynamic formulation used in condensed matter physics to simulate their evolution.

  92. K. A. Bugaev, M. I. Gorenstein, I. N. Mishustin, W. Greiner

    An exact analytical solution of the statistical multifragmentation model is found in thermodynamic limit. Excluded volume effects are taken into account in the thermodynamically self-consistent way. The model exhibits a 1-st order phase transition of the liquid-gas type. An extension of the model including the Fisher&#39;s term is also studied. The possibili

  93. A. D. Efimov, A. A. Pasternak, D. N. Doinikov, V. M. Mikhajlov

    Interpretation of the B(E2) values at energies higher the first backbending indicates that the maximum boson of IBM has to increase with energy and spin.

  94. D. V. Vinnik, A. V. Prozorkevich, S. A. Smolyansky, V. D. Toneev

    Aspects of the formation and equilibration of a quark-gluon plasma are explored using a quantum kinetic equation, which involves a non-Markovian, Abelian source term for quark and antiquark production and, for the collision term, a relaxation time approximation that defines a time-dependent quasi-equilibrium temperature and collective velocity. The strong Ab

  95. R. Kaczarowski, W. Plociennik, A. Syntfeld, H. Mach

    Total Routhian Surface (TRS) calculations were performed for the 149Ce nucleus. The equilibrium deformation parameters and total angular momentum values have been calculated as a function of rotational frequency for both signatures of the lowest positive- and negative-parity rotational bands. Theoretical predictions are compared with the results of experimen

  96. E895 Collaboration

    We report a particle source imaging analysis based on two-pion correlations in high multiplicity Au + Au collisions at beam energies between 2 and 8A GeV. We apply the imaging technique introduced by Brown and Danielewicz, which allows a model-independent extraction of source functions with useful accuracy out to relative pion separations of about 20 fm. The

  97. Paul Glendinning, Jan Abshagen, Tom Mullin

    Experimental observations of an almost symmetric electronic circuit show complicated sequences of bifurcations. These results are discussed in the light of a theory of imperfect global bifurcations. It is shown that much of the dynamics observed in the circuit can be understood by reference to imperfect homoclinic bifurcations without constructing an explici

  98. B. Malomed, K. Marinov, D. Pushkarov, A. Shivarova

    We consider (2+1)-dimensional beams, whose transverse size may be comparable to or smaller than the carrier wavelength, on the basis of an extended version of the nonlinear Schrödinger equation derived from the Maxwell`s equations. As this equation is very cumbersome, we also study, in parallel to it, its simplified version which keeps the most essential ter

  99. Alexander G. Ramm, Alexandra B. Smirnova

    A new continuous regularized Gauss-Newton-type method with simultaneous updates of the operator $(F^{\pr*}(x(t))F&#39;(x(t))+\ep(t) I)^{-1}$ for solving nonlinear ill-posed equations in a Hilbert space is proposed. A convergence theorem is proved. An attractive and novel feature of the proposed method is the absence of the assumptions about the location of t

  100. P. Duclos, O. Lev, P. Stovicek, M. Vittot

    We study the Floquet Hamiltonian: -i omega d/dt + H + V(t) as depending on the parameter omega. We assume that the spectrum of H is discrete, {h_m (m = 1..infinity)}, with h_m of multiplicity M_m. and that V is an Hermitian operator, 2pi-periodic in t. Let J > 0 and set Omega_0 = [8J/9,9J/8]. Suppose that for some sigma > 0: sum_{m,n such that h_m > h_n} mu_