The (π±,p) reactions and nuclear pp and pn correlations

Abstract
The authors have measured ( pi +or-, p) spectra for 3,4He and 27Al at theta =20 degrees and report on the two-nucleon pion absorption over the energy range 50-300 MeV. The pi +NN to Np and pi -pp to pn yields for T=0 NN systems in 3,4He are found to be larger than expected relative to pi +d to pp while they are smaller for T=1 systems and show a significant difference between 3He and 4He.