Effect of Bose-Einstein correlations on intermittency in ultrarelativistic nucleus-nucleus collisions

Abstract

The role of quantum correlations, the rescattering of the produced particles and mixing of events with various impact parameters on intermittency in nucleus-nucleus collisions at 200 A GeV is studied in the framework of the RQMD model. We generated an RQMD data sample with Bose-Einstein correlations of identical pion pairs included. One can get quantitative agreement with the measured intermittent behaviour of the pion pseudorapidity spectra if these quantum correlations are taken into account. MotivationsTo investigate properties of dynamical fluctuations in relativistic heavy ion collisions Bialas and Peschanski proposed to study the scaled factorial moments of the (pseudo) rapidity distribution of the final state particles and introduced the concept of intermittency into high energy nuclear physics [ 1 ]. The effect of intermittency is quantified by the power law behaviour of the scaled factorial moments (Fi) and loosely regarded as having fractal properties.Intermittent behaviour of spectra was observed in several experiments. After an early analysis of cosmic-ray events this effect has been observed in e+e -, muon-hadron, hadron-hadron, hadron-nucleus and nucleus-nucleus collisions [2], thus it seems to I E-mail: KUN@HUKLTE51.BITNET. Fax: 36-52-416181. be a universal feature of particle production at high energies.It is an important question whether the intermittency can be understood on the basis of our conventional physical knowledge or we should suspect new physics behind it. For answering this question it is necessary to study whether the commonly used models of particle production can account for the general features of the observed intermittent behaviour. This problem was studied using Fritiof, Jetset, Herwig, Pythia and Venus codes which generally give a good description of the single particle features observed in experiments. However, it was found that intermittency effects are much stronger in the measured data than in these Monte Carlo simulations. It means quantitatively that the anomalous fractal dimension~ (di) calculated from the experimental data are several times larger than those calculated from the models, otherwise, practically there was no intermittency (di "~ O) in several cases in the model calculations [2,8]. Fur-0370-2693/94/$07.00 (~)