Quasi-free pi(0) photoproduction from the bound nucleon

Abstract

Differential cross-sections for quasi-free pi(0) photoproduction from the proton and neutron bound in the deuteron have been measured for Egamma=200-400 MeV at theta(gamma)(lab)=136.2degrees using the Glasgow photon tagger at MAMI, the Mainz 48 cm empty set 64 cm NaI(Tl) photon detector and the Gottingen SENECA recoil detector. For the proton measurements made with both liquid-deuterium and liquid-hydrogen targets allow direct comparison of "free" pi(0) photoproduction cross-sections as extracted from the bound-proton data with experimental free cross-sections which are found to be in reasonable agreement below 320 MeV. At higher energies the "free" cross-sections extracted from quasi-free data are significantly smaller than the experimental free cross-sections and theoretical predictions based on multipole analysis. For the first time, "free" neutron cross-section have been extracted in the Delta-region. They are also in agreement with the predictions from multipole analysis up to 320 MeV and significantly smaller at higher photon energies.