Negative binomial distribution fits to multiplicity distributions in restricted δη intervals from central 16O+Cu collisions at 14.6A [formula omitted] and their implication for “intermittency”

Abstract

Fluctuations in pseudorapidity of charged particles from central (ZCAL) collisions of 16O+Cu at 14.6 A·GeV c have been analyzed by the E802 Collaboration using the method of normalized factorial moments as a function of the interval δη. In agreement with previous measurements, an apparent power-law growth of moments with decreasing interval is observed down to δη ∼ 0.1. Experience with e t distributions suggests that fluctuations of multiplicity and transverse energy can be well described by Gamma or Negative Binomial Distributions (NBD) and excellent fits to NBD were obtained in all δη bins. The k parameter of the NBD fit was found to increase linearly with the δη interval, which due to the well known property of the NBD under convolution, indicates that the multiplicity distributions in adjacent bins of pseudorapidity δη ∼ 0.1 are largely statistically independent.