Observation of a Quasideuteron Component in the ReactionC12(π+, 2p)

The reaction ${}_{}{}^{12}{}_{}{}^{}\mathrm{C}({\pi }^{+}, 2p)$ was studied at 165 and 245 MeV over a broad kinematic range by coincidence measurement of the outgoing protons. The $p-p$ angular correlations and proton energy spectra allow an identification of the "quasideuteron" component of the reaction. The angular distribution of this component has a shape similar to that of the ${\pi }^{+}d\to \mathrm{pp}$ reaction. It is found that one-step quasideuteron absorption accounts for at most 25% of the total absorption cross section.