πo photoproduction on quasi-free neutrons in the reaction γd → πo np in the Δ region |
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Authors: | M. I. Levchuk V. A. Petrun’kin M. Schumacher |
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Affiliation: | 1. B.I. Stepanov Institute of Physics, Belarussian Academy of Sciences, F. Scarina prospect 70, 220072, Minsk, Belarus 2. P.N. Lebedev Physical Institute, Russian Academy of Sciences, Leninsky prospect 53, 117924, Moscow, Russia 3. II. Physikalisches Institut der Universit?t G?ttingen, Bunsenstrasse 7-9, D-37073, G?ttingen, Germany
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Abstract: | The possibility of obtaining information about the reaction γn → πon in the Δ resonance region from the reaction γd → πonp is analyzed. To this aim, the differential cross sections d3σ/dEndΩπdΩn both for unpolarized particles and in case of polarized photons and deuterons as well as the asymmetry Σ for linearly-polarized photons are calculated at photon energies from 250 to 400 MeV in the diagrammatic approach. The contributions from the pole diagrams as well as one-loop diagrams both with n-p and π-N-rescattering are taken into account. The main contribution to the differential cross sections of πo photoproduction on the neutron in the quasi-free kinematics arises from the neutron pole diagram. The correction due to n-p rescattering decreases with increasing pion angle and becomes to be less than 8% at Θπ ≥ 90°. The contributions of the proton pole diagram and the one of π -N rescattering were found to be negligible. Background effects are more pronounced in the case of the asymmetry Σ. However, they are also strongly suppressed in the neutron quasi-free kinematics at photon energies above 300 MeV. |
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