Coupling of baryon resonances to the Nω channel Original Research Article

We estimate the resonance coupling strength fRNω and fRNρ 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 fRNρ with values obtained from fitting the hadronic decay widths into Nρ. 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 Breit–Wigner model. Finally, we study how the properties of ω mesons in nuclear matter are affected from the excitation of resonance–hole loops. For an ω at rest, we find a broadening of about 40 MeV, while at higher momenta the effect of resonance excitations is reduced.