The Kolmogorov-Smirnov test and its use for the identification of fireball fragmentation

Physical Review C (Impact Factor: 3.72). 02/2009; 80:024904. DOI: 10.1103/PhysRevC.80.024904
Source: arXiv

ABSTRACT We propose an application of the Kolmogorov-Smirnov test for rapidity distributions of individual events in ultrarelativistic heavy ion collisions. The test is particularly suitable to recognise non-statistical differences between the events. Thus when applied to a narrow centrality class it could indicate differences between events which would not be expected if all events evolve according to the same scenario. In particular, as an example we assume here a possible fragmentation of the fireball into smaller pieces at the quark/hadron phase transition. Quantitative studies are performed with a Monte Carlo model capable of simulating such a distribution of hadrons. We conclude that the Kolmogorov-Smirnov test is a very powerful tool for the identification of the fragmentation process. Comment: 9 pages, 10 figures

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    ABSTRACT: It is explained why and how the fireball created in ultrarelativistic nuclear collisions can fragment when passing the phase transition. It can happen at the first-order phase transition but is not excluded even at high collision energies where the smooth crossover is present. Two potential observables sensitive to the appearance of fragmentation are reviewed: event-by-event changes of rapidity distributions and proton correlation in relative rapidity. Comment: 6 pages, proceedings from Excited QCD 2010, Jan 31 - Feb 6, 2010, Tatranska Lomnica, Slovakia

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