Photoproduction of negative pion from deuterium at laboratory energies 600 to 1250 MeV and C.M. pion production angles 6 degrees to 160 degrees

摘要

NOTE: Text or symbols not renderable in plain ASCII are indicated by [...]. Abstract is included in .pdf document.The differential cross sections for reaction [...] have been measured for laboratory photon energies between 600 and 1250 MeV, using a liquid deuterium target. The measurements were made using a magnetic spectrometer and a recoil counter in which [...] and [...] were detected in various combinations. Measurements of the [...] counting rate, the [...] counting rate ration, and the [...], p coincidence counting rate were used to calculate three independent values for the [...] photoproduction cross section. The cross sections from the latter two measurements were less sensitive to deuterium effects and were averaged to form the set of final data. The most notable feature of the data is the absence of an enhancement near the [...] resonance. This feature has been predicted from quark model calculations. The [...] resonance appears to be excited by a helicity 3/2 amplitude as was the case in [...] photoproduction.