TWO TOPICS IN PION PHYSICSⅠ. PHOTOPRODUCTION OF NEUTRAL PIONS FROM COMPLEX NUCLEI AND THE PAIR-CORRELATION FUNCTION Ⅱ. THE RELATIVE RATE OF ABSORPTION OF NEGATIVE PIONS IN HYDROGEN AND DEUTERIUM

摘要

A simple theory of the photoproduction of Π° mesons from complex nuclei based, on the impulse and closure approximation is studied. The theory is compared with an experiment of Goodwin, Anderson, and Kenney in which, with a single counter, they observed the dependence of the number of decay gammas from Π° mesons photo-produced from various nuclei as a function of the atomic number at 45, 90, and 135 degrees for incident photon energies from threshold to 350 MeV, The dependence they measure near threshold and at 45 degrees does not agree with the simple theory nor is it consistent with partial elastic, production as they claim. By a method of Placaek and Wick the corrections to the simple theory are estimated and found to be large near threshold.