Pion absorption on He3 at T=62.5 and 82.8 MeV

Pion absorption in He3 was studied at T=62.5 and 82.8 MeV using nucleon-nucleon coincidences. For + absorption on proton-neutron pairs the differential cross section is the same as that for ++d p+p except for an increase by a factor of about 1.5. For - absorption on the proton-proton pair, the differential cross section is asymmetric about 90°, indicating possible isospin mixing. The total cross sections pn(+) are 10.2 0.9 mb and 13.5 1.3 mb at 62.5 and 82.8 MeV and for pp(-) are 0.70 0.07 mb and 0.92 0.10 mb at 62.5 and 82.8 MeV. The three-body absorption cross sections for + and - are found to be comparable to each other and show no strong energy dependence. The three-body absorption cross section 3(+) is 6.7 2.5 mb and 5.7 2.3 mb and for -, 3(-) is 8.7 1.4 mb and 6.5 2.0 mb at 62.5 and 82.8 MeV, respectively.