Event-by-event multiplicity fluctuations and correlations in ring-like and jet-like events in 197Au–AgBr collisions at 11.6 A GeV/c

Abstract

Event-by-event (ebe) multiplicity fluctuations and correlations amongst the charged particles emitted in the forward–backward symmetric pseudorapidity ([Formula: see text]) windows of varying widths and positions are investigated by analyzing the experimental data on [Formula: see text]Au–AgBr collisions at 11.6[Formula: see text]A[Formula: see text]GeV/[Formula: see text]. The findings are compared with the predictions of relativistic transport model, urqmd and independent particle emission (or mixed event) model. It is observed that the fluctuations in ebe mean pseudorapidity values and those reflected from the fluctuations strength measure, [Formula: see text] are relatively higher as compared to those expected from the statistically independent particle emission model. The study of the variance, [Formula: see text] of a suitably defined forward–backward asymmetry variable [Formula: see text] as a function of [Formula: see text] window width and position indicates the presence of strong short-range correlations, which might arise due to isotropic decay of cluster-like objects either in forward or backward [Formula: see text] region. Furthermore, analyses of events having ring-like and jet-like substructures, carried out separately, suggest that the major contribution to the observed fluctuations in the data sample are due to ring-like events, while the contributions from the jet-like events appear to be rather small. The observed difference in the behavior of correlation strengths from the two types of events might be due to the enhanced emission of Cherenkov gluons, giving rise to the ring-like substructure. The mixed event analysis further confirms that the observed fluctuations are the distinct feature of the data, which disappear after event mixing.