Pion Absorption onT=1Nucleon Pairs atTπ=70MeV

Angular correlations of the ${}_{}{}^{6,7}{}_{}{}^{}\mathrm{Li}({\pi }^{\pm },pn)$ cross sections were measured in a wide angular range at $T_{\pi }=70\mathrm{}$ MeV. The components of the two-nucleon absorption processes were extracted, and the angular distributions of the cross sections were obtained. Strong asymmetries about 90° were observed for the reactions ${}_{}{}^{6,7}{}_{}{}^{}\mathrm{Li}({\pi }^{\pm },pn)$, and the cross sections were much larger than that of ${}_{}{}^3{}_{}{}^{}\mathrm{He}$. These results show the importance of the ${\sigma }_{11}$ component in pion absorption on $T=1\mathrm{}$ nucleon pairs for $p$-shell nuclei.