47,400 research outputs found

    Ground State Structure of a Coupled 2-Fermion System in Supersymmetric Quantum Mechanics

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    We prove the uniqueness of the ground state for a supersymmetric quantum mechanical system of two fermions and two bosons, which is closely related to the N=1 WZ-model. The proof is constructive and gives detailed information on what the ground state looks like.Comment: 8 pages, LaTe

    Quark and Gluon Orbital Angular Momentum and Spin in Hard Processes

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    We suggest a method of constructing gauge invariant quark and gluon distributions that describe an abstract QCD observable and apply this method to analyze angular momentum of a hadron. In addition to the known quark and gluon polarized structure functions, we obtain gauge invariant distributions for quark and gluon orbital angular momenta, and consider some basic properties of these distributions and their moments.Comment: 16 pages, no figures, RevTe

    Scalar Meson Decay Constants and the Nature of the a_0(980)

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    The a_0(980), a_0(1450) and K_0(1430) decay constants are determined using a form of QCD sum rules known to produce a very accurate determination of the rho decay constant. The ratio of a_0(980) to K_0(1430) decay constants is shown to be ~0.6, ruling out both the ``loosely-bound-K\bar{K}-molecule'' and Gribov minion scenarios for the a_0(980). Solutions for the isovector scalar spectral function obtained in the literature from sum rule analyses employing a more restrictive single-resonance-plus-continuum form of the input spectral ansatz, are also investigated. These solutions, which suggest, in contrast to the present results, negligible coupling of the a_0(980) to the isovector scalar density are shown to produce a poor quality match between the OPE and hadronic sides of the sum rules employed here, and hence to be strongly disfavored relative to the present solution.Comment: Presented to the International Conference on Quark Nuclear Physics, Adelaide, Feb. 21-25, 200

    On the QCD Evolution of the Transversity Distribution

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    The QCD evolution of the transversity distributions is investigated and compared to that of the helicity distributions. It is shown that they differ largely in the small-xx region. It is also proved that the evolution preserves Soffer's inequality among the three leading-twist distribution functions.Comment: 9 pages, 1 figur

    Raymond Stora and Les Houches 1970

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    The marvelous Les Houches summer school of 1970 bore the trademark of Raymond Stora
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