16,124 research outputs found

    Vector Mesons and Baryon Resonances in Nuclear Matter

    Get PDF
    We calculate the effect of many-body interactions in nuclear matter on the spectral function of ρ\rho and ω\omega meson. In particular, we focus on the role played by baryon resonances in this context.Comment: 4 pages, 4 figures, to be published in proceedings of the Third International Conference on Perspectives on Hadronic Physics, 7 - 11 May 2001, Miramare-Trieste, Ital

    Vector Meson Decay of Baryon Resonances

    Get PDF
    We investigate the coupling of vector mesons with nucleons to nucleon resonances in an isospin-selective VMD approach and explore the in-medium properties of vector mesons.Comment: 8 pages, 2tables, 4 figures, invited talk at NSTAR 2001, Workshop on the Physics of Excited Nucleons, University of Mainz, Germany, March 7-10, 2001. To be published in World Scientifi

    Coupling of Baryon Resonances to the NωN \omega channel

    Full text link
    We estimate the resonance coupling strength fRNωf_{RN\omega} and fRNρf_{RN\rho} from a Vector Meson Dominance (VMD) analysis. The isoscalar and isovector part of the photon coupling are obtained separately from helicity amplitudes. The reliability of this approach is tested by comparing VMD predictions for fRNρf_{RN\rho} with values obtained from fitting the hadronic decay widths into NρN \rho. A reasonable agreement is found, but VMD tends to underestimate the coupling constants. In order to confirm consistency with experimental data, we calculate the cross-sections for photon-and pion induced reactions within a {\it Breit-Wigner} model. Finally, we study how the properties of ω\omega mesons in nuclear matter are affected from the excitation of resonance-hole loops. For an ω\omega at rest, we find a broadening of about 40 MeV, while at higher momenta the effect of resonance excitations is reduced.Comment: 21 pages, 5 ps figures, misprints corrected, discussion added, improved calculation of gamma N -> omega N, revised version to be published in Nuclear Physics