Correlations in particle production in pion-proton interactions at 40 GeV/c

Results of the investigation of some correlation effects in π−p interactions at 40 GeV/c incident momentum are given. On the basis of 2 000 events the dependence of the transverse momenta of π+ and π− mesons on the longitudinal momenta was obtained, as well as two- particle distributions for various pion pairs, and correlation functions C(y1, y2) and R(y1, y2). For π+π− pairs R(0,0) = 0.65 ± 0.07 and the correlation length is L = 1.8 ± 0.2 for −1 ⩽ y1, y2 ⩽ 1. For π+π+ and π−π− pairs R(0,0) = 0.26 ± 0.10. Comparison of these results with proton-proton data at 200 GeV and at ISR energies suggests that limiting behaviour in two- particle distributions R(y1,y2) for π−p interactions is already reached at 40 GeV.