Photoproduction of πΔ(1236) from protons below 1.1 GeV

The π + and π − momentum spectrum of the reaction γ p → ππ N have been measured at lab angles 20°, 40°, 60° and 90° and photon energies 0.744, 0.844, 0.944 and 1.044 GeV with a magnetic spectrometer using the photon subtraction method. Both spectra show a peak corresponding to the production of the πΔ(1236) state. The analysis has been carried out with amplitudes for the quasi two-body process γ p → πΔ (1236) and a phase-space background so as to reproduce both π + and π − spectra. The ratio of cross sections σ ( γ p → π + Δ 0 )/ ( γ p → π − Δ ++ ) is found to vary 0.0 to 1.8, depending on kinematical conditions.