Pion photoproduction on 14N at 173 MeV photon energy

Abstract

The reaction 14 N(γ, π +) 14 C g.s. has been measured at a photon energy of 173 MeV and various pion angles at the Mainz microtron via the (e, π) reaction. Single differential cross sections were extracted using the virtual-photon theory. We have compared our data with momentum-space DWIA calculations using Blomqvist-Laget operators and pion wave functions distorted by an optical potential of Stricker, McManus and Carr. In a comparison with the Cohen-Kurath shell model and phenomenological A= 14 wave functions we show that the Cohen-Kurath wave functions overestimate the data up to a factor of 4, while a wave function recently proposed by Huffman et al. gives very good agreement. The analysis rise to new speculations on the forbidden 14C beta decay.