Two classes of reaction mechanism in π± interactions at 8 to 23 GeV/c

Abstract The longitudinal correlations between the proton and the most forwardly produced beam-like pion ( π f ) are studied in the reactions π ± + p → π f ± + p + anything at 8, 16 and 23 GeV/c. Maxima are observed in the two-particle inclusive cross sections which can be interpreted as resulting mainly from (a) diffractive processes and (b) mechanisms of central particle production. The average multiplicity of final state particles is lower and increases more slowly with increasing energy for diffractive processes than for the central production.