Coherentπ0 photoproduction on12C,13C and16O in theΔ (1232) resonance region

π0 photoproduction has been measured on12C,13C and16O in theΔ-resonance region. By limiting the acceptance of theπ0 spectrometer to small angles (Θ≦10°), only the coherent channel could contribute. The data show a broadening of the resonance width whereas the peak energy remains essentially unchanged. Theoretical calculations give considerably lower values compared with our data.