Proton-proton correlations inAr40+197Au reactions and the role of the two-particle phase space

Proton-proton correlations at small relative momenta were measured for [sup 40]Ar+[sup 197]Au reactions at [ital E]/[ital A]=200 MeV. Comparing the correlation functions to predictions based on single-particle phase space distributions from microscopic Boltzmann-Uehling-Uhlenbeck and quantum-molecular-dynamics (QMD) simulations, no satisfactory agreement could be established. Calculations utilizing two-particle emission probabilities predicted by the QMD model differ significantly from the single-particle calculations and are much closer to the experimental observations at [ital E]/[ital A]=200 MeV, potentially signaling the importance of the two-particle density for the proton-proton correlation function.