Linear momentum transfer in pion accompanied 16O induced reaction on 232Th at 95 MeV per nucleon

Positive pions and protons emitted at 90° were measured in coincidence with two fission fragments in the reaction 16O + 232Th at 95 MeV/nucleon. The linear momentum transfer distribution has been determined from the folding angle between the fragments. The average momentum transfer is 2.5 GeV/c ± 0.2 GeV/c for a pionic reaction. An analysis in terms of impact parameter distributions leads to the conclusion that subthreshold pion production requires a large overlap of projectile and target density profiles.