( π + , p ) and ( π + , d ) reactions on light nuclei

The (..pi../sup +/,p) and (..pi../sup +/,d) reactions on 1p shell nuclei are studied between T/sub ..pi../ = 32 and 81 MeV. Cross sections both to the continuum and to discrete two body final states are given. The spectra and angular distributions of the (..pi../sup +/,p) continuum are examined in terms of a two-nucleon pion absorption mechanism. The /sup 12,13/C(..pi../sup +/,p) spectra of discrete states are similar to the corresponding /sup 12,13/C(p,d) spectra at the same momentum transfer. The /sup 16/O(..pi../sup +/,p)/sup 15/O(g.s.) transition is found to have an abnormally small cross section relative to other transitions of similar spectroscopic strength. The two-neutron pickup (..pi../sup +/,d) data to discrete states is the first published data on this reaction. The (..pi../sup +/,d) reaction is found to favor strongly transitions in the 1p shell of angular momentum transfer L = 2. The relative strength of these L = 2 transitions varies the same way as the corresponding (p,t) cross sections. No L = 0 transitions are clearly identifiable. The (..pi../sup +/,d) angular distributions are compared to the calculations of Betz and Kerman. The calculations reproduce well the absolute magnitude and shape of the (..pi../sup +/,d) angular distributions but fail to predict the L dependence, pion energy dependence, and possibly even the spin transfer dependence of the (..pi../sup +/,d) cross sections.