A Study of Pion Photoproduction on Carbon-12 in the Delta Resonance Region

Abstract

This thesis describes a study of the 12 C(gamma; pie + n) reaction in the Delta resonance re­ gion using tagged photons. The experiment was accomplished using the MAMI­B c.w. electron accelerator at the Institut f¨ur Kernphysik, Mainz. Bremsstrahlung photons, created when 855 MeV electrons strike a 4 ¯m Nickel radiator, were tagged with a 2 MeV resolution using the Glasgow tagging spectrometer installed in the MAMI A2 experimental hall.

The data is presented as triple and (by integrating over the pion energy) double differential cross sections. A comparison is made with Distorted Wave Impulse Approximation (DWIA) predictions generated by the code THREEDEE. It is concluded that more reliable theoretical calculations are required. In particular, a better treatment of the distortion and absorption of the outgoing particles is needed. Initial comparisons with the microscopic theory of Carrasco are attempted and the problems faced in making such a comparison are described and solutions suggested.