Angular Correlations and Distributions inp¯pAnnihilation into Eight and Nine Pions at 5.7 GeV/c

Appreciable angular correlations between pions have been observed for both $\overline{p}+p\to 4{\pi }^{+}+4\mathrm{}{\pi }^{-}$ and $\overline{p}+p\to 4{\pi }^{+}+4\mathrm{}{\pi }^{-}+{\pi }^0$ reactions. Deviation between the angular correlation predicted by the phase-space calculations and our experimental values seems to occur for definite-momentum configurations of the produced pions. The secondaries are not emitted in a jet structure, i.e., the transverse and c.m. longitudinal momentum of the pions are in satisfactory agreement with phase predictions. By comparing the results of this experiment with other $\overline{p}p$ data, some systematics seem to emerge for the angular distribution of secondary pions.