Short range rapidity correlations from the Bose-Einstein effect and multiplicity fluctuations in heavy-ion collisions— an experimental demonstration

Abstract

A measurement of the two-particle correlation of identified pions was performed E802 E859 magnetic spectrometer on the interval 1.5 ≤ y ≤ 2.0, δφ = 0.4 rad, for central 28Si+Au collisions. It is demonstrated that the two-pion correlation in rapidity is entirely due to Bose-Einstein interference. The directly measured exponential correlation length is ζ y = 0.20 ± 0.03 for two π −, with strenght ( R(0, 0) ∼ 1%, in agreement with previous E802 indirect measurements derived from an analysis of intermittency using Negative Binomial Distributions.