Event-by-event analysis of high-multiplicity events produced in 158 A GeV/c ²⁰⁸Pb-²⁰⁸Pb collisions

¹ Department of Physics, Aligarh Muslim University - 202002, Aligarh, India
² Department of Applied Physics, Aligarh Muslim University - 202002, Aligarh, India
³ Department of Physics, Banaras Hinud University - 221005, Varanasi, India

^(a) Shakeel.Ahmad@cern.ch
^(b) bksingh@bhu.ac.in

Received: 1 July 2015
Accepted: 2 November 2015

Abstract

An extensive analysis of individual high-multiplicity events produced in  ²⁰⁸Pb-²⁰⁸Pb collisions is carried out by adopting different methods to examine the anomalous behavior of these rare events. A method of selecting the events with densely populated narrow regions or spikes out of a given sample of collision events is discussed. Employing this approach two events with large spikes in their η- and ϕ-distributions are selected for further analysis. For the sake of comparison, another two events which do not exhibit such spikes are simultaneously analyzed. The findings suggest that systematic studies of particle density fluctuations in one- and two-dimensional phase spaces and a comparison with those obtained from the studies of correlation-free Monte Carlo events, would be useful for identifying the events with large dynamical fluctuations. Formation of clusters or jet-like phenomena in multihadronic final states in individual events is also discussed and the experimental findings are compared with the independent particle emission hypothesis by carrying out Monte Carlo simulations.