Properties of the matter created in heavy ion collisions – results from the PHOBOS experiment

Abstract

In the collisions of ultrarelativistic heavy ions the energy of the nuclei is released in a small volume leading to the creation of a hot and dense nuclear matter. The study of the particles produced from it gives the information on the conditions in the early stage of the collision and the evolution of the system. The PHOBOS experiment provides unique data on the particle production in the almost full phase space and down to very small transverse momenta. This overview shortly presents the most important features of the nucleus-nucleus collisions observed by the PHOBOS experiment, but concentrates on the most recent studies. The extensive analyses of charged particles production are based on the multiplicity measurements in a very wide pseudorapidity range and reveal strong short and long range correlations. The correlations with a high p T trigger particle extends at least 4 units in pseudorapidity, while two-particle correlations suggest production of particles in large and wide clusters. © Copyright owned by the author(s) under the terms of the Creative Commons Attribution-NonCommercial-ShareAlike Licence.