Determination of the Centrality of Nuclear Collisions Using a Hadron Calorimeter

Abstract

The determination of the centrality of the collision or the magnitude of the impact parameter of the collision of heavy nuclei is of great importance for the analysis of all experimental data and comparison with theory. One method is to measure the number of spectators using a hadron calorimeter located at a small angle to the nuclear beam. It was shown that with an achievable energy resolution of the hadron calorimeter, the accuracy of determining the collision parameter is insufficient for using the calorimeter in the MPD/NICA and CBM/FAIR projects. The error reaches 35% at a beam energy of 2.5 GeV, even for peripheral collisions. Secondary processes during the passage of spectators through the nucleus give an additional contribution to the error for central collisions and at medium centralities.