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

Abstract 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 ( y 1 , y 2 ) and R ( y 1 , y 2 ). For π + π − pairs R (0,0) = 0.65 ± 0.07 and the correlation length is L = 1.8 ± 0.2 for −1 ⩽ y 1 , y 2 ⩽ 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 ( y 1 , y 2 ) for π − p interactions is already reached at 40 GeV.