Evidence of a two-source emission for light charged particles in coincidence with pions produced in 16O + 27Al collisions at 94 MeV/nucleon

Light charged particles associated with subthreshold neutral pion emission in the16O+27Al reaction

“…The inclusive absolute cross section of neutral pions in this reaction has been already reported [9] as 150 gb. The data for charged pions were obtained from a previous experiment on the same system at the same bombarding energy, where the pions were detected at 90 ~ by a range telescope [10]. To make such a comparison, the same ratio between (dNH/dOH) and N~ was reported, where N~ now stands for the number of charged pions emitted at 90 ~ As it can be seen, the ~0 results are quite comparable to those for charged pions.…”

“…3). Coincidence data are here compared to the inclusive an- [ 10] and normalized to the coincidence data at 4 ~ is also shown gular distribution of He ions (solid line). The inclusive cross section was normalized to the coincidence data at 4% By such a comparison one can see that the slope is different, suggesting that more violent collisions are selected when triggering with pions, since in this case the angular distribution is flatter than for the inclusive case.…”

“…Correlations between light charged particles and charged pions have already been studied around 100 MeV/nucleon, in experiments where the pions were detected by a range telescope and the associated light particles were measured in large area multidetectors [10][11]. The availability of large acceptance ~0 spectrometers recently built [12][13][14][15][16][17][18] allows now to plan more detailed exclusive experiments, in which both neutral mesons and light charged particles can be detected in a wide solid angle.…”

“…These exclusive data were taken to provide an overall check of the system, and to make a comparison with previously measured data on exclusive charged pion production in the same collision at the same bombarding energy [ 10,11 ].…”