Coupling of baryon resonances to the N omega channel

We estimate the resonance couplings strength f(RN omega) and f(RN rho) from a Vector Meson Dominance (VMD) analysis. The isoscalar and isovector part of the photon coupling are obtained separately from helicity amplitudes. Th e reliability of this approach is tested by comparing VMD predictions fur f (RN rho) with values obtained from fitting the hadronic decay widths into N rho. A reasonable agreement is found, but VMD tends to underestimate the c oupling constants. In order to confirm consistency with experimental data, we calculate the cross-sections for photon- and pion-induced reactions with in a Breit-Wigner model. Finally, we study how the properties of omega meso ns in nuclear matter are affected from the excitation of resonance-hole loo ps. For an omega at rest, we find a broadening of about 40 MeV, while at hi gher momenta the effect of resonance excitations is reduced. (C) 2001 Elsev ier Science B.V. All rights reserved.