1,191 research outputs found

    A Relation Between Approaches to Integrability in Superconformal Yang-Mills Theory

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    We make contact between the infinite-dimensional non-local symmetry of the typeIIB superstring on AdS5xS5 worldsheet theory and a non-abelian infinite-dimensional symmetry algebra for the weakly coupled superconformal gauge theory. We explain why the planar limit of the one-loop dilatation operator is the Hamiltonian of a spin chain, and show that it commutes with the g*2 N = 0 limit of the non-abelian charges.Comment: 19 pages, harvma

    Higher Order Polarizabilities of the Proton

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    Compton scattering results are used to probe proton structure via measurement of higher order polarizabilities. Values for αE2p,βE2p,αEνp,\alpha_{E2}^p,\beta_{E2}^p,\alpha_{E\nu}^p, βEνp\beta_{E\nu}^p determined via dispersion relations are compared to predictions based upon chiral symmetry and from the constituent quark model. Extensions to spin-polarizabilities are also discussed.Comment: 18 pages, revised version with one reference adde

    Hough Transform Search for Continuous Gravitational Waves

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    This paper describes an incoherent method to search for continuous gravitational waves based on the Hough transform, a well-known technique used for detecting patterns in digital images. We apply the Hough transform to detect patterns in the time-frequency plane of the data produced by an earth-based gravitational wave detector. Two different flavors of searches will be considered, depending on the type of input to the Hough transform: either Fourier transforms of the detector data or the output of a coherent matched-filtering type search. We present the technical details for implementing the Hough transform algorithm for both kinds of searches, their statistical properties, and their sensitivities

    Baryon Density Correlations in High Temperature Hadronic Matter

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    As part of an ongoing effort to characterize the high temperature phase of QCD, in a numerical simulation using the staggered fermion scheme, we measure the quark baryon density in the vicinity of a fixed test quark at high temperature and compare it with similar measurements at low temperature and at the crossover temperature. We find an extremely weak correlation at high temperature, suggesting that small color singlet clusters are unimportant in the thermal ensemble. We also find that at T=0.75 TcT = 0.75\ T_c the total induced quark number shows a surprisingly large component attributable to baryonic screening. A companion simulation of a simple flux tube model produces similar results and also suggests a plausible phenomenological scenario: As the crossover temperature is approached from below, baryonic states proliferate. Above the crossover temperature the mean size of color singlet clusters grows explosively, resulting in an effective electrostatic deconfinement.Comment: 26 pp, RevTeX, 12 postscript figures, combined in a single shell archive file. (Also available in 13 postscript files by anonymous ftp from einstein.physics.utah.edu, /pub/milc/paper.sh.Z.

    Considerations on rescattering effects for threshold photo- and electro-production of π0\pi^0 on deuteron

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    We show that for the S-state π0\pi^0-production in processes γ+d→d+π0\gamma+d\to d+\pi^0 and e−+d→e−+d+π0e^-+d\to e^-+d+\pi^0 the rescattering effects due to the transition: γ+d→p+p+π− \gamma+d\to p+p+\pi^- (or n+n+π+)→d+π0n+n+\pi^+)\to d+\pi^0 are cancelled out due to the Pauli principle. The large values for these effects predicted in the past may result from the fact that the spin structure of the corresponding matrix element and the necessary antisymmetrization induced by the presence of identical protons (or neutrons) in the intermediate state was not taken into account accurately. One of the important consequences of these considerations is that π0\pi^0 photo- and electro-production on deuteron near threshold can bring direct information about elementary neutron amplitudes.Comment: Add a new sectio

    Compton Scattering and the Spin Structure of the Nucleon at Low Energies

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    We analyze polarized Compton scattering which provides information on the spin-structure of the nucleon. For scattering processes with photon energies up to 100 MeV the spin-structure dependence can be encoded into four independent parameters-the so-called spin-polarizabilities γi,i=1...4\gamma_i, i=1...4 of the nucleon, which we calculate within the framework of the "small scale expansion" in SU(2) baryon chiral perturbation theory. Specific application is made to "forward" and "backward" spin- polarizabilities.Comment: 8 pages revtex file, separation between pion-pole and regular contributions detailed + minor wording changes, results and conclusions unchange
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