Pion absorption in nuclei: the (π/sup +/-/, p) reactions

Pion absorption in nuclei has been studied using (π/sup +/-/,p) reactions in the region of the delta resonance. Reported here is the first experiment to measure the excitation of discrete final states following the (π-, p) reaction. At EPICS these reactions was measured at T/sub π/ = 120 MeV and theta/sub lab/ = 250 on 24Mg, 27Al, 40Ca and 58Ni; 12C(π-,p) was measured at T/sub π/ = 145 MeV. At πM1-SUSI these reactions were measured at T/sub π/ = 90 MeV and at theta/sub lab/ = 200 on 23Na and 24Mg. The measurement includes both the differential cross sections and continuum up to an excitation energy of 40 MeV. The shape of the continuum in an excitation energy range of 10 to 40 MeV was found to be independent of pion charge and target mass. The magnitude of proton yield from all the targets at T/sub π/ = 120 MeV is more than twenty four times larger for π+ than for π-. At T/sub π/ = 90 MeV the ratio of the proton yield for π+ to π- adsorption drops down to fourteen