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July 1999 arXiv papers — page 5

Showing 401500 of 2,413 papers

  1. I. Hinchliffe, F. E. Paige

    We present an example of a scenario of particle production and decay in supersymmetry models in which the supersymmetry breaking is transmitted to the observable world via gravitational interactions. The case is chosen so that there is a large production of tau leptons in the final state. It is characteristic of large tan beta in that decays into muons and e

  2. Henri Bachacou, Ian Hinchliffe, Frank E. Paige

    This paper presents new measurements in a case study of the minimal SUGRA model with m_0=100 GeV, mhalf=300 GeV, A_0=0, tan(beta)=2.1, and mu=+1 based on four-body distributions from three-step decays and on minimum masses in such decays. These measurements allow masses of supersymmetric particles to be determined without relying on a model. The feasibility

  3. Christian W. Bauer, Craig N. Burrell

    We study nonperturbative corrections up to O(1/m_b^3) in the inclusive rare B decay B -> X_s l^+ l^- by performing an operator product expansion. The values of the matrix elements entering at this order are unknown and introduce uncertainties into physical quantities. Imposing a phase space cut to eliminate the $c \bar{c}$ resonances we find that the O(1/m_b

  4. Deirdre Black, Amir H. Fariborz, Joseph Schechter

    Recent work suggests the existence of a non-conventional lowest-lying scalar nonet containing the a0(980). Then the a0(1450) and also the K0*(1430) are likely candidates to belong to a conventional p-wave $q \bar q$ nonet. However a comparison of their properties with those expected on this basis reveals a number of puzzling features. It is pointed out that

  5. Johan Bijnens

    I : Chiral Perturbation Theory is introduced and its applications to semileptonic and nonleptonic kaon decays are discussed. II: The method of large $N_c$ is used to calculate $K\toππ$ nonleptonic matrix elements, in particular the matching procedure between long and short-distance evolution that takes all scheme dependence correctly into account is discusse

  6. John C. Collins

    This talk summarized the proof of hard-scattering factorization for hard exclusive electroproduction processes: deeply virtual Compton scattering and exclusive meson production.

  7. V. Barone, C. Pascaud, F. Zomer

    A new QCD analysis of Deep Inelastic Scattering (DIS) data is presented. All available neutrino and anti-neutrino cross sections are reanalysed and included in the fit, along with charged-lepton DIS and Drell-Yan data. A massive factorisation scheme is used to describe the charm component of the structure functions. Next-to-leading order parton distribution

  8. A. Gehrmann-De Ridder, G. Kramer, H. Spiesberger

    We study the production of photons accompanied by jets in large-Q2 deep inelastic scattering. Numerical results for the cross section differential with respect to the fraction of momentum z_gamma carried by a photon inside a jet at large z_gamma, up to O(alpha alpha_s) in perturbative QCD, are presented. The sensitivity to the fragmentation contribution allo

  9. G. F. Giudice, A. Riotto, I. Tkachev

    Many models of supersymmetry breaking, in the context of either supergravity or superstring theories, predict the presence of particles with weak scale masses and Planck-suppressed couplings. Typical examples are the scalar moduli and the gravitino. Excessive production of such particles in the early Universe destroys the successful predictions of nucleosynt

  10. K. G. Chetyrkin, M. Steinhauser

    The relation between the on-shell quark mass and the mass defined in the modified minimal subtraction scheme is computed up to order α_s^3. Implications for the numerical values of the top and bottom quark masses are discussed. We show that the new three-loop correction significantly reduces the theoretical uncertainty in the determination of the quark masse

  11. Giovanni Amelino-Camelia, Joseph Kapusta

    Above a critical matter density the propagating modes of the neutral kaon system are essentially eigenstates of strangeness, but below it they are almost complete eigenstates of CP. We estimate the real and imaginary parts of the energies of these modes and their mixing at all densities up to nuclear matter density $2\times 10^{14}$ g/cm$^3$. In a heavy ion

  12. M. G. Ryskin, A. G. Shuvaev, Yu. M. Shabelski

    We compare the theoretical status and the numerical predictions of two approaches for heavy quark production in the high energy hadron collisions, namely the conventional LO parton model with collinear approximation and $k_T$-factorization approach. The main assumptions used in the calculations are discussed. To extract the differences coming from the matrix

  13. Masahide Yamaguchi

    We investigate the evolution of the global string network in the radiation dominated universe by use of numerical simulations in 3+1 dimensions. We find that the global string network settles down to the scaling regime where the energy density of global strings, $ρ_{s}$, is given by $ρ_{s} = ξμ/ t^2$ with $μ$ the string tension per unit length and the scalin

  14. Konstantin T. Matchev, Damien M. Pierce

    We determine the Tevatron's reach in supersymmetric parameter space in trilepton, like-sign dilepton, and dilepton plus tau-jet channels, taking all relevant backgrounds into account. We show results for the minimal supergravity model. With a standard set of cuts we find that the previously unaccounted for $Wγ^\ast$ background is larger than all other ba

  15. B. I. Ermolaev, S. I. Troyan

    The asymptotical behaviour of the magnetic form factor for electron and quark is obtained in the double-logarithmic approximation for the Sudakov kinematics, i.e. for the case when the value of the transfer momentum is much greater than the mass of the particle.

  16. J. Ambjorn, J. Giedt, J. Greensite

    We find that Polyakov lines, computed in abelian-projected SU(2) lattice gauge theory in the confined phase, have finite expectation values for lines corresponding to two units of the abelian electric charge. This means that the abelian-projected lattice has at most Z(2), rather than U(1), global symmetry. We also find a severe breakdown of the monopole domi

  17. BES Collaboration, J. Z. Bai

    The first measurement of B(0->phi X0) and an upper limit for B(D+->phi X+) are determined from 22.3 pb-1 of e+e- annihilation data at a C. M. energy of 4.03 GeV. The data were recorded by the Beijing Spectrometer (BES) at BEPC. A recoil charge method is applied for the first time to charm threshold data to determine the charge of the D meson in the recoil fr

  18. The SLD Collaboration, K. Abe

    The lifetimes of B+ and B0 mesons have been measured using the entire sample of 550,000 hadronic Z0 decays collected by the SLD experiment at the SLC between 1993 and 1998. In this paper, we describe the inclusive analysis of the 350,000 hadronic Z0 decays collected in 1997-98 with the upgraded SLD vertex detector. In this data period, a high statistics samp

  19. The SLD Collaboration, K. Abe

    We present a new preliminary measurement of the parity-violation parameter Ab using a self-calibrating vertex-charge technique. In the SLD experiment we observe hadronic decays of polarized Z bosons produced in collisions between longitudinally polarized electrons and unpolarized positrons at the SLAC Linear Collider. A sample of bb events is selected using

  20. Shinji Mukohyama

    There have been many attempts to understand the statistical origin of black-hole entropy. Among them, entanglement entropy and the brick wall model are strong candidates. In this paper we show a relation between entanglement entropy and the brick wall model: the brick wall model seeks the maximal value of the entanglement entropy. In other words, the entangl

  21. C. G. Torre

    We present some remarkable properties of the symmetry group for gravitational plane waves. Our main observation is that metrics with plane wave symmetry satisfy every system of generally covariant vacuum field equations except the Einstein equations. The proof uses the homothety admitted by metrics with plane wave symmetry and the scaling behavior of general

  22. M. O. Katanaev

    The constructive method of conformal blocks is developed for the construction of global solutions for two-dimensional metrics having one Killing vector. The method is proved to yeild a smooth universal covering space with a smooth pseudo-Riemannian metric. The Schwarzschild, Reisner--Nordstrom solutions, extremal black hole, dilaton black hole, and constant

  23. Sergey V. Zuev

    The Kähler metric which has been constructed by present author is used in this paper to find an exact solution of Einstein equations with energy-momentum tensor of special type. The type of $T_{ij}$ admits in particular to use it as energy-momentum tensor of charged scalar field and in case of such system the field function is determined.

  24. Scott Nicholson

    Because the World Wide Web is a dynamic collection of information, the Web search tools (or "search engines") that index the Web are dynamic. Traditional information retrieval evaluation techniques may not provide reliable results when applied to the Web search tools. This study is the result of ten replications of the classic 1996 Ding and Marchioni

  25. Matthew Horton, Ian Affleck

    The exact form factor for the O(3) non-linear sigma model is used to predict the three-magnon contribution to the spin correlation function, S(q,w), near wavevector q=pi in an integer spin, one-dimensional antiferromagnet. The three-magnon contribution is extrememly broad and extremely weak; the integrated intensity is <2% of the single-magnon contribution.

  26. Takashi Hotta, Seiji Yunoki, Elbio Dagotto

    The magnetic structure of LaMnO$_3$ is investigated on three-dimensional clusters of MnO$_6$ octahedra by using a combination of relaxation and Monte Carlo techniques. It is found that the cooperative Jahn-Teller phonons lead to the stabilization of A-type antiferromagnetic and C-type orbital structures in the physically relevant region of parameter space fo

  27. Youngah Park, Michael E. Fisher

    Lattice and continuum fluid models with repulsive-core interactions typically display a dominant, critical-type singularity on the real, negative activity axis. Lai and Fisher recently suggested, mainly on numerical grounds, that this repulsive-core singularity is universal and in the same class as the Yang-Lee edge singularities, which arise above criticali

  28. Yan Levin, Jeferson J. Arenzon, Jurgen F. Stilck

    Comment on the paper of Ha and Liu (Phys. Rev. Lett. {\bf 79}, 1289 (1997)) regarding the nature of attraction between like charged rods. We demostrate that their results do not produce the correct low temperature limit.

  29. G. M. Zassenhaus, J. D. Reppy

    We have performed a high resolution specific heat measurement on 4He completely filling the pores of Vycor glass. Within 10mK of the superfluid transition we have found a peak in the heat capacity which is only 0.02% the size of the background. The peak can be fit with a rounded version of the ``logarithmic singularity&#39;&#39; observed in bulk 4He. Along w

  30. J. Burki, C. A. Stafford

    In a recent letter (Phys.Rev.Lett. 82, 1526 (1999)), van den Brom and van Ruitenbeek found a pronounced suppression of the shot noise in atom-size gold contacts with conductances near integer multiples of $G_0=2e^2/h$, revealing unambiguously the quantized nature of the electronic transport. However, the ad hoc model they introduced to describe the contribut

  31. Ido Kanter, David Saad

    The efficacy of a specially constructed Gallager-type error-correcting code to communication in a Gaussian channel is being examined. The construction is based on the introduction of complex matrices, used in both encoding and decoding, which comprise sub-matrices of cascading connection values. The finite size effects are estimated for comparing the results

  32. Vinay Ambegaokar, Aashish Clerk

    The emergence of a direction of time in statistical mechanics from an underlying time-reversal-invariant dynamics is explained by examining a simple model. The manner in which time-reversal symmetry is preserved and the role of initial conditions are emphasized. An extension of the model to finite temperatures is also discussed.

  33. Youngho Park, Shoudan Liang

    We calculate the local correlation functions of charge and spin for the one-chain and two-chain Hubbard model using the density matrix renormalization group method and the recursion technique. Keeping only finite number of states we get good accuracy for the low energy excitations. We study the charge and spin gaps, bandwidths and weights of the spectra for

  34. Tunna Baruah, Rajendra R. Zope, Anjali Kshirsagar

    Electron momentum density and Compton profiles in Lithium along $<100 >$, $<110>$, and $<111>$ directions are calculated using Full-Potential Linear Augmented Plane Wave basis within generalized gradient approximation. The profiles have been corrected for correlations with Lam-Platzman formulation using self-consistent charge density. The first and second de

  35. Ido Kanter, David Saad

    A method for improving the performance of sparse-matrix based parity check codes is proposed, based on insight gained from methods of statistical physics. The advantages of the new approach are demonstrated on an existing encoding/decoding paradigm suggested by Sourlas. We also discuss the application of the same method to more advanced codes of a similar ty

  36. N. Shibata, H. Tsunetsugu

    The finite-T DMRG method is applied to the one-dimensional Kondo lattice model to calculate dynamic correlation functions. Dynamic spin and charge correlations, S_f(omega), S_c(omega), and N_c(omega), and quasiparticle density of states rho(omega) are calculated in the paramagnetic metallic phase for various temperatures and hole densities. Near half filling

  37. G. I. Japaridze, E. Müller-Hartmann

    In this paper we study the ground state phase diagram of a one-dimensional $t-U-J$ model, at half-filling. In the large-bandwidth limit and for ferromagnetic exchange with easy-plane anisotropy, a phase with gapless charge and massive spin excitations, characterized by the coexistence of triplet superconducting ($TS$) and spin density wave ($SDW^{z}$) instab

  38. Steffen Trimper

    An Ising model with local Glauber dynamics is studied under the influence of additional kinetic restrictions for the spin-flip rates depending on the orientation of neighboring spins. Even when the static interaction between the spins is completely eliminated and only an external field is taken into account the system offers a phase transition at a finite va

  39. L. Van Look, E. Rosseel, M. J. Van Bael, K. Temst

    Shapiro voltage steps at voltages V_n=nV_0 (n integer) have been observed in the voltage-current characteristics of a superconducting film with a square lattice of perforating microholes (antidots)in the presence of radiofrequent radiation. These equidistant steps appear at the second matching field H_2 when the flow of the interstitial vortex lattice in the

  40. Satya N. Majumdar

    This is a brief review of recent theoretical efforts to understand persistence in nonequilibrium systems. Some of the recent experimental results are also briefly mentioned. I also discuss recent generalizations of persistence in various directions and conclude with a summary of open questions.

  41. Jijun Zhao, Alper Buldum, Jianping Lu, C. Y. Fong

    The structural and electronic properties of germanium clathrates Ge$_{46}$ and K$_8$Ge$_{46}$ are studied by first principles calculations within the local density approximation. The equilibrium structures are obtained by {\em ab initio} pseudopotential calculation combined with dynamic minimizations. The clathrate structure is found as a low energy phase fo

  42. N. D. Caranicolas, Ch. L. Vozikis

    We investigate the properties of motion in a map model derived from a galactic Hamiltonian made up of perturbed elliptic oscillators. The phase space portrait is obtained in all three different cases using the map and numerical integration of the equations of motion. Our numerical calculations suggest that the map describes very well the properties of regula

  43. B. Barbanis, H. Varvoglis, Ch. L. Vozikis

    A model, plane symmetric, 3-D potential, which preserves some features of galactic problems,is used in order to examine the phase space structure through the study of the properties of orbits crossing perpendicularly the plane of symmetry. It is found that the lines formed by periodic orbits, belonging to Farey sequences, are not smooth neither continuous. I

  44. I. Varga, P. Pollner, B. Eckhardt

    We show that strongly localized wave functions occur around classical bifurcations. Near a saddle node bifurcation the scaling of the inverse participation ratio on Planck&#39;s constant and the dependence on the parameter is governed by an Airy function. Analytical estimates are supported by numerical calculations for the quantum kicked rotor.

  45. S. Boldyrev, A. Schekochihin

    We study geometric properties of a random Gaussian short-time correlated velocity field by considering statistics of a passively advected metric tensor. That describes universal properties of fluctuations of tensor objects frozen into the fluid and passively advected by it. The problem of one-point statistics of co- and contravariant tensors is solved exactl

  46. Sunetra Giridhar, David L. Lambert, Guillermo Gonzalez

    Chemical compositions are derived from high-resolution spectra for three stars classed as SRd variables in the General Catalogue of Variable Stars. These stars are shown to be metal-poor supergiants: WY And with [Fe/H] = -1.0, VW Eri with [Fe/H] = -1.8, and UW Lib with [Fe/H] = -1.2. Their compositions are identical to within the measurement errors with the

  47. Manoj Kaplinghat, Robert E. Lopez, Scott Dodelson, Robert J. Scherrer

    A massive neutrino which decays after recombination (t > 10^{13} sec) into relativistic decay products produces an enhanced integrated Sachs-Wolfe effect, allowing constraints to be placed on such neutrinos from present cosmic microwave background anisotropy data. Previous treatments of this problem have approximated the decay products as an additional compo

  48. Mary-Helen Armour, David R. Ballantyne, Gary J. Ferland, Jennifer Karr

    This paper outlines a way to determine the ICF using only infrared data. We identify four line pairs, [NeIII] 36$\micron$/[NeII] 12.8$\micron$, [NeIII]~15.6$\micron$ /[NeII] 12.8$\micron$, [ArIII] 9$\micron$/[ArII] 6.9$\micron$, and [ArIII] 21$\micron$/[ArII] 6.9$\micron$, that are sensitive to the He ICF. This happens because the ions cover a wide range of

  49. Ken&#39;ichi Nomoto, Hideyuki Umeda, Izumi Hachisu, Mariko Kato

    Relatively uniform light curves and spectral evolution of Type Ia supernovae (SNe Ia) have led to the use of SNe Ia as a ``standard candle&#39;&#39; to determine cosmological parameters, such as the Hubble constant, the density parameter, and the cosmological constant. Whether a statistically significant value of the cosmological constant can be obtained dep

  50. John F. Hawley

    Global time-dependent simulations provide a means to investigate time-dependent dynamic evolution in accretion disks. This paper seeks to extend previous local simulations by beginning a systematic effort to develop fully global three-dimensional simulations. The nonlinear development of the magnetorotational instability is investigated using a time-explicit

  51. Ian McHardy, Anthony Lawson, Andrew Newsam, Alan Marscher

    From a combination of high quality X-ray observations from the NASA Rossi X-ray Timing Explorer (RXTE), and infrared observations from the UK Infrared Telescope (UKIRT) we show that the medium energy X-ray (3-20 keV) and near infrared fluxes in the quasar 3C273 are highly correlated. It is widely believed that the X-ray emission in quasars like 3C273 arises

  52. E. Schinnerer, A. Eckart, L. J. Tacconi

    Sub-arcsecond IRAM Plateau de Bure mm-interferometric observations of the 12CO (2-1) line emission in the Seyfert~1 NGC 3227 and the Seyfert~2 NGC 1068 have revealed complex kinematic systems in the inner 100 pc to 300 pc that are not consistent with pure circular motion in the host galaxies. Modeling of these kinematic systems with elliptical orbits in the

  53. P. Morel, B. Pichon, J. Provost, G. Berthomieu

    Using the most recent updated physics, calibrated solar models have been computed with the new thermonuclear reaction rates of NACRE, the recently available European compilation. Comparisons with models computed with the reaction rates of Caughlan & Fowler (\cite{cf88}) and of Adelberger et al. (\cite{a98}) are made for global structure, expected neutrinos f

  54. Pavel Kroupa

    The results obtained by Kroupa, Petr & McCaughrean (1999) for specific models of young compact binary-rich clusters are generalised using dynamical scaling relations, to infer the candidate set of possible birth models leading to the Orion Nebula Cluster (ONC), of which the Trapezium Cluster is the core. It is found that candidate sets of solutions exist whi

  55. Johan H. Knapen, Isaac Shlosman, Reynier F. Peletier

    We present a detailed study of the bar fraction in the CfA sample of Seyfert galaxies, and in a carefully selected control sample of non-active galaxies, to investigate the relation between the presence of bars and of nuclear activity. To avoid the problems related to bar classification in the RC3, e.g., subjectivity, low resolution and contamination by dust

  56. Alessandro Marconi, Ethan Schreier, Anton Koekemoer, Alessandro Capetti

    We report new HST WFPC2 and NICMOS observations of the center of the nearest radio galaxy Centaurus A (NGC 5128) and discuss their implications for our understanding of the active nucleus and jet. We detect the active nucleus in the near-IR (K and H) and, for the first time, in the optical (I and V), deriving the spectral energy distribution of the nucleus f

  57. P. Giommi, P. Padovani, E. Perlman

    We present the results of six BeppoSAX observations of 1ES 2344+514, five of which were taken within a week. 1ES 2344+514, one of the few known TeV BL Lac objects, was detected by the BeppoSAX Narrow Field Instruments between 0.1 to \~50 keV. During the first five closely spaced observations 1ES 2344+514 showed large amplitude luminosity variability, associa

  58. Gabriele Ghisellini

    Recent results of the hectic research activity about gamma-ray bursts will be reviewed, with emphasis about the emission processes at the origin of the observed gamma-rays. The conventional synchrotron shock scenario is found to have problems, due to the very short cooling times of the emitting electrons, which implies a predicted spectrum F(nu) proportional

  59. Peter Berczik

    A new Chemo-Dynamical Smoothed Particle Hydrodynamic (CD-SPH) code is presented. The disk galaxy is described as a multi-fragmented gas and star system, embedded in a cold dark matter halo with a rigid potential field. The star formation (SF) process, SNII, SNIa and PN events, and the chemical enrichment of gas, have all been considered within the framework

  60. R. J. Protheroe

    Nature produces cosmic ray particles, probably protons, with energies well above $10^{20}$ eV -- how are they produced? Where do they come from? Gamma rays with energies above $10^{13}$ eV are produced in jets of active galaxies -- are these produced by energetic electrons or protons? What is the correct model of Gamma Ray Bursts? These are just some of the

  61. S. L. Mader, W. J. Zealey, Q. A. Parker, M. R. W. Masheder

    We present the results of a photographic and CCD imaging survey for Herbig-Haro (HH) objects in the L1630 and L1641 giant molecular clouds in Orion. The new HH flows were initially identified from a deep H-alpha film from the recently commissioned AAO/UKST H-alpha Survey of the southern sky. Our scanned H-alpha and broad band R images highlight both the impr

  62. F. Yusef-Zadeh, W. M. Goss, D. A. Roberts, B. Robinson

    A survey of the inner 8$^\circ \times 1^\circ$ of the Galactic plane toward the Galactic center has been carried out at the 1720 MHz transition of OH molecule using the VLA in its D configuration with a resolution of $\approx70&#39;&#39;\times45&#39;&#39;$. The detection of compact 1720 MHz OH masers associated with three supernova remnants G357.7+0.3, G1.13

  63. A. Kempf

    It is usually believed that a function whose Fourier spectrum is bounded can vary at most as fast as its highest frequency component. This is in fact not the case, as Aharonov, Berry and others drastically demonstrated with explicit counter examples, so-called superoscillations. It has been claimed that even the recording of an entire Beethoven symphony can

  64. Thomas Vojta, D. Belitz, T. R. Kirkpatrick, R. Narayanan

    We investigate the quantum phase transition of itinerant ferromagnets. It is shown that correlation effects in the underlying itinerant electron system lead to singularities in the order parameter field theory that result in an effective long-range interaction between the spin fluctuations. This interaction turns out to be generically {\em antiferromagnetic}

  65. Paul Wiggins, Dong Lai

    We present a semi-analytic study of the equilibrium models of close binary systems containing a fluid star (mass $m$ and radius $R_0$) and a Kerr black hole (mass $M$) in circular orbit. We consider the limit $M\gg m$ where spacetime is described by the Kerr metric. The tidally deformed star is approximated by an ellipsoid, and satisfies the polytropic equat

  66. H. O. Meyer, J. T. Balewski, J. Doskow, R. E. Pollock

    We report a measurement of the spin-dependent total cross section ratios delta_sigma_T/sigma_tot and delta_sigma_L/sigma_tot of the pp --> pp pi^0 reaction between 325 MeV and 400 MeV. The experiment was carried out with a polarized internal target in a storage ring. Non-vertical beam polarization was obtained by the use of solenoidal spin rotators. Near thr

  67. A. V. Afanasjev, J. K&#34;onig, P. Ring

    Cranked Relativistic Hartree-Bogoliubov (CRHB) theory is presented as an extension of Relativistic Mean Field theory with pairing correlations to the rotating frame. Pairing correlations are taken into account by a finite range two-body force of Gogny type and approximate particle number projection is performed by Lipkin-Nogami method. This theory is applied

  68. U. Aglietti, G. Ricciardi

    The shape function f(k_+) describes Fermi motion effects in inclusive semi-leptonic decays such as B -> X_u+e+nu near the end-point of the lepton spectrum. We compute the leading one-loop corrections to the shape function f(k_+) in the effective theory with a hard cut-off regularization. The matching constant onto full QCD is infrared safe, i.e. the leading

  69. A. B. Arbuzov

    Radiative corrections due to pair production in process of electron-positron annihilation are considered. The main attention is paid to the corrections of the third order. Simultaneous emission of photons and pairs is taken into account. The leading log approximation and convolution procedure are used. Exponentiation is discussed. Theoretical uncertainty in

  70. J. C. Romao, M. A. Diaz, M. Hirsch, W. Porod

    The simplest unified extension of the Minimal Supersymmetric Standard Model with bi-linear R--Parity violation provides a predictive scheme for neutrino masses which can account for the observed atmospheric and solar neutrino anomalies in terms of bi-maximal neutrino mixing. The maximality of the atmospheric mixing angle arises dynamically, by minimizing the

  71. M. A. Sanchis-Lozano

    We re-analyze Tavatron data on charmonium hadroproduction in the framework of the color-octet model implemented in the event generator PYTHIA taking into account initial-state radiation of gluons and Altarelli-Parisi evolution of final-state gluons fragmenting into $c\bar{c}$ pairs. We obtain new values for the color-octet matrix elements relevant to this pr

  72. Erkan Tuzel, Ayse Erzan

    A coarse grained model of a random polypeptide chain, with only discrete torsional degrees of freedom and Hookean springs connecting pairs of hydrophobic residues is shown to display stretched exponential relaxation under Metropolis dynamics at low temperatures with the exponent $β\simeq 1/4$, in agreement with the best experimental results. The time depende

  73. S. Y. Choi, Jae Sik Lee

    We study Higgs boson decays in the minimal supersymmetric standard model where the tree-level CP invariance of the Higgs potential is explicitly broken by loop effects of soft CP-violating Yukawa interactions related to scalar quarks of the third generation. The scalar-pseudoscalar mixing among two neutral CP-even Higgs bosons and one CP-odd Higgs boson due

  74. V. M. Braun, A. Khodjamirian, M. Maul

    We present a quantitative analysis of the electromagnetic pion form factor in the light-cone sum rule approach, including radiative corrections and higher-twist effects. The comparison to the existing data favors the asymptotic profile of the pion distribution amplitude and allows to estimate the deviation: $(\int du/u ϕ_π(u))/ (\int du/u ϕ^{\rm as}_π(u))=$

  75. Giovanni Landi

    In the spirit of noncommutative geometry we construct all inequivalent vector bundles over the $(2,2)$-dimensional supersphere $S^{2,2}$ by means of global projectors $p$ via equivariant maps. Each projector determines the projective module of finite type of sections of the corresponding `rank 1&#39; supervector bundle over $S^{2,2}$. The canonical connectio

  76. Igor Frenkel, Naihuan Jing, Weiqiang Wang

    Given a finite group $\Gamma$ and a virtual character $\wt$ on it, we construct a Fock space and associated vertex operators in terms of representation ring of wreath products $\Gamma\sim S_n$. We recover the character tables of wreath products $\Gamma\sim S_n$ by vertex operator calculus. When $\Gamma$ is a finite subgroup of $SU_2$, our construction yields

  77. John D. Barrow, Joao Magueijo

    We show that the Supernovae results, implying evidence for an accelerating Universe, may be closely related to the recent discovery of redshift dependence in the fine structure constant $α$. The link is a class of varying speed of light (VSL) theories which contain cosmological solutions similar to quintessence. During the radiation dominated epoch the cosmo

  78. Daniel S. Freed, Edward Witten

    We analyze global anomalies for elementary Type II strings in the presence of D-branes. Global anomaly cancellation gives a restriction on the D-brane topology. This restriction makes possible the interpretation of D-brane charge as an element of K-theory.

  79. C. P. Burgess, N. R. Constable, R. C. Myers

    We compute the high-temperature limit of the free energy for four-dimensional N=4 supersymmetric SU(N_c) Yang-Mills theory. At weak coupling we do so for a general ultrastatic background spacetime, and in the presence of slowly-varying background gauge fields. Using Maldacena's conjectured duality, we calculate the strong-coupling large-N_c expression for th

  80. Moshe Havilio, Assa Auerbach

    A fundamental connection between superconductivity and quantum spin fluctuations in underdoped cuprates, is revealed. A variational calculation shows that {\em Cooper pair hopping} strongly reduces the local magnetization $m_0$. This effect pertains to recent neutron scattering and muon spin rotation measurements in which $m_0$ varies weakly with hole doping

  81. Thorsten Feldmann

    I review to which extent the properties of pseudoscalar mesons can be understood in terms of the underlying quark (and eventually gluon) structure. Special emphasis is put on the progress in our understanding of eta-eta&#39; mixing. Process-independent mixing parameters are defined, and relations between different bases and conventions are studied. Both, the

  82. B. A. Kniehl, A. A. Penin

    In the framework of nonrelativistic QCD, we consider a new class of radiative corrections, which are generated at next-to-next-to-next-to-leading order through the chromoelectric dipole interaction of heavy quarkonium with ultrasoft virtual gluons. We provide analytical formulae from which the resulting shifts in the quarkonium energy levels and the wave fun

  83. Mattias Marklund, Gert Brodin, Peter Dunsby

    We consider the interaction of a weak gravitational wave with electromagnetic fields in a thin plasma on a Minkowski background spacetime using the 1+3 orthonormal frame formalism. Because gravitational and electromagnetic waves satisfy the same dispersion relation, electromagnetic waves can be effectively generated as a result of this interaction. In the ca

  84. HongSheng Zhao, David Graff, Puragra Guhathakurta

    There are lines of evidence suggesting that some of the observed microlensing events in the direction of the Large Magellanic Cloud (LMC) are caused by ordinary star lenses as opposed to dark Machos in the Galactic halo. Efficient lensing by ordinary stars generally requires the presence of one or more additional concentrations of stars along the line of sig

  85. J. A. Helayel-Neto, A. Penna-Firme, I. L. Shapiro

    We consider some aspects of conformal symmetry in a metric-scalar-torsion system. It is shown that, for some special choice of the action, torsion acts as a compensating field and the full theory is conformally equivalent to General Relativity on classical level. Due to the introduction of torsion, this equivalence can be provided for the positively-defined

  86. Li Gang Jin, Chong Sheng Li, Robert J. Oakes, Shou Hua Zhu

    We calculate the Yukawa corrections of order $O(\alpha_{ew}m_{t(b)}^{2}/m_{W}^{2})$ to charged Higgs boson production in association with a top quark at the Tevatron and the LHC. The corrections are not very sensitive to the mass of the charged Higgs boson and can exceed -20% for low values of $\tan\beta$, where the contribution of the top quark is large, an

  87. Georg Drenkhahn, Tom Richtler

    SN1994D of type Ia has been suspected not to fit into the relation between decline rate, colour, and brightness. However, an individual distance of its host galaxy, NGC4526, other than that of the Virgo cluster, has not yet been published. We determined the distance by the method of globular cluster luminosity functions on the basis of HST archive data. A ma

  88. K. Tsushima, K. Saito, A. W. Thomas

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

  89. Hideo Hasegawa

    Spike-train responses of single Hodgkin-Huxley (HH) and integrate-and-fire (IF) neurons with and without the refractory period, are calculated and compared. The HH and IF neurons are assumed to receive spike-train inputs with the constant interspike intervals (ISIs) and stochastic ISIs given by the Gamma distribution, through excitatory and inhibitory synapt

  90. S. Mancini, V. I. Man&#39;ko

    The spectrum of light scattered from a Bose-Einstein condensate is studied in the limit of particle-number conservation. To this end, a description in terms of deformed bosons is invoked and this leads to a deviation from the usual predict spectrum&#39;s shape as soon as the number of particles decreases.

  91. S. Mancini, A. Gatti, L. A. Lugiato

    We show the possibility of noiseless amplification of an optical image in cavities containing a parametric oscillator. We consider a confocal ring cavity with plane mirrors and compare with the case of planar cavity. In the latter case the system operates with severe spatial limitations, while in the confocal case, there is the possibility of preserving the

  92. Rudolf Ahlswede, Peter Loeber

    We prove a data processing inequality for quantum communication channels, which states that processing a received quantum state may never increase the mutual information between input and output states.

  93. Eqab M. Rabei, Arvind, R. Simon, N. Mukunda

    We develop the widest possible generalisation of the well-known connection between quantum mechanical Bargmann invariants and geometric phases. The key notion is that of null phase curves in quantum mechanical ray and Hilbert spaces. Examples of such curves are developed. Our generalisation is shown to be essential to properly understand geometric phase resu

  94. Erhard Bieberich

    Current quantum theories of consciousness suggest a configuration space of an entangled ensemble state as global work space for conscious experience. This study will describe a procedure for adjustment of the singlet evolution of a quantum computation to a classical signal input by action potentials. The computational output of an entangled state in a single

  95. Shi-Hai Dong, Zhong-Qi Ma, Giampiero Esposito

    The Schrodinger equation for stationary states is studied in a central potential V(r) proportional to the inverse power of r of degree beta in an arbitrary number of spatial dimensions. The presence of a single term in the potential makes it impossible to use previous algorithms, which only work for quasi-exactly-solvable problems. Nevertheless, the analysis

  96. Tomoyuki Yamakami, Andrew C. Yao

    Adleman, DeMarrais, and Huang introduced the nondeterministic quantum polynomial-time complexity class NQP as an analogue of NP. Fortnow and Rogers implicitly showed that, when the amplitudes are rational numbers, NQP is contained in the complement of C_{=}P. Fenner, Green, Homer, and Pruim improved this result by showing that, when the amplitudes are arbitr

  97. Stephan I. Tzenov

    We solve the Vlasov equation for the longitudinal distribution function and find stationary wave patterns when the distribution in the energy error is Maxwellian. In the long wavelength limit a stability criterion for linear waves has been obtained, and a Korteweg-de Vries-Burgers equation for the relevant hydrodynamic quantities has been derived.

  98. Carl Balslev Clausen, Yuri S. Kivshar, Ole Bang, Peter L. Christiansen

    We analyse nonlinear wave propagation and cascaded self-focusing due to second-harmonic generation in Fibbonacci optical superlattices and introduce a novel concept of nonlinear physics, the quasiperiodic soliton, which describes spatially localized self-trapping of a quasiperiodic wave. We point out a link between the quasiperiodic soliton and partially inc

  99. A. V. Afanasjev, P. Ring

    The cranked relativistic mean field (CRMF) theory is applied for the description of superdeformed (SD) rotational bands observed in $^{153}$Ho. The question of the structure of the so-called SD band in $^{154}$Er is also addressed and a brief overview of applications of CRMF theory to the description of rotating nuclei at extreme conditions is presented.

  100. H. Molique, J. Dobaczewski, J. Dudek

    Superdeformed configurations in 32S, and in neighboring nuclei 33S, 31S, 33Cl, and 31P, are determined within the Hartree-Fock approach with the Skyrme interaction. Energies, angular momenta, quadrupole moments, particle-emission Q-values, and relative alignments and quadrupole moments are calculated for a number of superdeformed rotational bands in these nu