The in-medium properties of the ${\mathrm{D}}_{13}\left(1520\right)$ nucleon resonance were studied via photoproduction of ${\pi }^0$ mesons from nuclei (C, Ca, Nb, Pb) with the TAPS detector at the Mainz Microton accelerator. The inclusive (single and multiple pion production) data disagree with model predictions which explain the disappearance of the second resonance bump in total photoabsorption via a medium modification of the ${\mathrm{D}}_{13}\to \mathrm{N}\rho$ decay. The exclusive single ${\pi }^0$ production data show no broadening of the resonance structure beyond Fermi smearing. Both results together cast doubt on attempts to explain the vanishing of the second resonance bump for nuclei by a broadening of the ${\mathrm{D}}_{13}$ resonance.

• Received 4 January 2001

DOI:https://doi.org/10.1103/PhysRevLett.86.4764