Double Photoproduction of Neutral Pions on a Proton and a Deuteron

详细

Total cross sections of electromagnetic π⁰π⁰ formation processes on a proton and a deuteron in the photon energy range from threshold to E_γ ≤ 2 GeV are calculated. Construction of the single-particle photoproduction operator is based on a calculation of Born and resonance contributions calculated in the tree approximation. The main parameters of the nucleon resonances were found from the Particle Data Group (PDG) compilation. A satisfactory description of the р(γ, π⁰π⁰)р cross section was achieved assuming a leading role for the pion rescattering process π⁺π^– → π⁰π⁰, whose contribution amounted to more than 1 μb in the vicinity of the D₁₃(1520) resonance.