Large-angle correlations observed in intermediate energy heavy ion collisions

Large-angle correlations between light particles emitted in 12C-induced nuclear collisions on various targets at 85 MeV/nucleon are studied. An excess of back-to-back correlations in the scattering plane is observed for all targets and all particle combinations. The strength of the excess depends on the particle masses and on the target mass in a way which could be qualitatively explained by momentum conservation within a recoiling participant source. Indications of a direct α-α scattering process in the reaction 12C+12C are observed. (orig.)