d/p and t/p ratios in nucleon-nucleus and heavy ion reactions: Can entropybe determined? art. no. 024601

The relative yields of high energy deuterons and tritons as compared to pro tons have been measured in p+Kr, O-16+Kr and Ne-20+Ar reactions with a cont inuously varying beam energy up to 500A (400A) MeV. Statistical (expanding) evaporation models are not able to reproduce these d/p or t/p ratios, whic h for high particle energy (>30 MeV) increase smoothly with beam energy. Mo dels that contain nucleon-nucleon scattering, Like cascade or nuclear molec ular dynamics models, can only reproduce the ratios if a final-state intera ction is introduced via the coalescence prescription. The coalescence radiu s that best fit the data is rather constant over wide beam energy intervals . Entropy can, however, not be directly determined from these ratios. [S055 6-2813(99)05607-1].