Testing the Core-Halo Model on Bose-Einstein Correlation Functions

Abstract

Having first performed a Monte Carlo simulation to justify the analysis technique to be used, we then analyze the Bose-Einstein correlation functions from CERN experiment NA44 in the context of the core-halo model. Although experimental resolution and error bar distribution prevents a direct observation of the halo structure, the values for the core radius and the core fraction of pions can be obtained in a straight-forward manner. These are found to be independent of the structure of the correlation function at small relative momenta of Q < 50 MeV. Hence, the omega meson decay products do not distort the Gaussian shape of the Bose-Einstein correlation function in S + Pb -> pi + pi + X reaction at CERN SPS. As we find that the "model-independent" HBT radii yield results that are quantitatively as well as qualitatively unreliable for systems with long-lived resonances, we present their corrected form that applies for correlation functions with lambda(K) < 1.