“…The curves show calculated angular distributions for pions, assumed isotropic in the nucleonnucleon center of mass. The results of the v.ork described atove as well as other emulsion experiments by the University of Lund group (27)(28)(29)(30)(31)(32)(33)(34) were in qualitative agreerrE11t with the hypothesis that the nucleusnucleus interaction can be described as a superposition of independent nucleon-nucleon (18,22,24,25), nucleon-nucleus (26), or a-a (23) collisions. However, notable discrepancies remained• (Figure 3) 1) The apparent recoil velocity, B ~ 0.02, of the residual target nucleus, as evident from the forward: backward ratios ~ 1.4 for low energy (;:5 30 A MeV) fragments (black tracks, in emulsion tenninology)…”