573 research outputs found

    B-Mesons on the Transverse Lattice

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    We present results from a first study of BB-mesons that is based on a transverse lattice formulation of light-front QCD. The shape of the Isgur-Wise form factor is in very good agreement with experimental data. However, the calculations yield rather large values for fBf_B and Λˉ\bar{\Lambda} compared to contemporary calculations based on other techniques.Comment: invited talk given at CSSM workshop on `Lattice Hadron Physics', Cairns, July 2001 and at ECT* workshop on `Light-cone Physics: Particles and String', Trento, Sept. 200

    Quark Correlations and Single Spin Asymmetries

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    We analyze the Sivers asymmetry in light-cone gauge. The average transverse momentum of the quark distribution is related to the correlation between the quark distribution and the transverse component of the gauge field at x±x^-\pm \infty. We then use finiteness conditions for the light-cone Hamiltonian to relate the transverse gauge field at x=±x^-=\pm \infty to the color density integrated over xx^-. This result allows us to relate the average transverse momentum of the active quark to color charge correlations in the transverse plane.Comment: 8 pages, 1 figur

    Impact Parameter Space Interpretation for Generalized Parton Distributions

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    The Fourier transform of generalized parton distribution functions at xi=0 describes the distribution of partons in the transverse plane. The physical significance of these impact parameter dependent parton distribution functions is discussed. In particular, it is shown that they satisfy positivity constraints which justify their physical interpretation as a probability density. The generalized parton distribution H is related to the impact parameter distribution of unpolarized quarks for an unpolarized nucleon, H-tilde is related to the distribution of longitudinally polarized quarks in a longitudinally polarized nucleon, and EE is related to the distortion of the unpolarized quark distribution in the transverse plane when the nucleon has transverse polarization.Comment: addtl. corrections, 34 page

    Finiteness Conditions for Light-Front Hamiltonians

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    In the context of simple models, it is shown that demanding finiteness for physical masses with respect to a longitudinal cutoff, can be used to fix the ambiguity in the renormalization of fermions masses in the Hamiltonian light-front formulation. Difficulties that arise in applications of finiteness conditions to discrete light-cone quantization are discussed.Comment: REVTEX, 9 page

    A 3+1 Dimensional Light-Front Model with Spontaneous Breaking of Chiral Symmetry

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    We investigate a 3+1 dimensional toy model that exhibits spontaneous breakdown of chiral symmetry, both in a light-front (LF) Hamiltonian and in a Euclidean Schwinger-Dyson (SD) formulation. We show that both formulations are completely equivalent --- provided the renormalization is properly done. For the model considered, this means that if one uses the same transverse momentum cutoff on the SD and LF formulations then the vertex mass in the LF calculation must be taken to be the same as the current quark mass in the SD calculation. The kinetic mass term in the LF calculation is renormalized non-trivially, which is eventually responsible for the mass generation of the physical fermion of the model.Comment: 6 pages, REVTE

    QCD on a transverse lattice

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    We present results from a transverse lattice study of low lying mesons. Special emphasis is put on the issue of Lorentz invariant energy-momentum dispersion relations for these mesons. The light-cone wave function for the π\pi obtained in this framework is very close to its asymptotic shape.Comment: 10 pages, sprocl.sty, invited talk given at 5th International Workshop on Particle Phyiscs Phenomenology, Chi-Pen, Taitung, Taiwan, 8-11 Nov 200