Tc. Awes et al., AZIMUTHAL CORRELATIONS IN THE TARGET FRAGMENTATION REGION OF HIGH-ENERGY NUCLEAR COLLISIONS, Physics letters. Section B, 381(1-3), 1996, pp. 29-34
Results on the target mass dependence of proton and pion pseudorapidit
y distributions and of their azimuthal correlations in the target rapi
dity range -1.73 less than or equal to eta less than or equal to 1.32
are presented. The data have been taken with the Plastic-Ball detector
set-up for 4.9 GeV p+Au collisions at the Berkeley BEVALAC acid for 2
00 A . GeV/c p-, O-, and S-induced reactions on different nuclei at th
e CERN-SPS. The yield of protons at backward rapidities is found to be
proportional to the target mass. Although protons show a typical ''ba
ck-to-back'' correlation, a ''side-by-side'' correlation is observed f
or positive pions, which increases both with target mass and with impa
ct parameter of a collision. The data can consistently be described by
assuming strong rescattering phenomena including pion absorption effe
cts in the entire excited target nucleus.