Neutron-proton interferometry in 30A MeV 40Ar+197Au collisions☆

Abstract Neutron-proton correlation functions in 30A MeV 40 Ar + 197 Au , 12 C , CH 2 reactions have been measured. In contrast to the nn and pp correlations, which exhibit the shape expected from quantum symmetrization effects and nuclear+Coulomb (pp) final-state interaction, the np function shows much less correlation strength. This may be due to Coulomb repulsion on the proton and/or to a larger effective spin than expected. Selecting high energy nucleons strengthens both the np and pp correlations.