Event patterns (particle scatter plots) extracted from charged particle spectra in pp and Pb-Pb collisions at 2.76 TeV

Abstract

The transverse momentum (p T) and pseudorapidity (η) spectra of charged particles produced in proton-proton (pp) and lead-lead (Pb-Pb) collisions at the Large Hadron Collider (LHC) are described by a hybrid model. In the model, the p T spectrum is described by a two-component distribution which contains an inverse power-law suggested by quantum chromodynamic calculus and an Erlang distribution resulted from a multisource thermal model. The η spectrum is described by a Gaussian rapidity (y) distribution resulted from the Landau hydrodynamic model and the two-component p T distribution, where the conversion between y and η is accurately considered. The modelling results are in agreement with the experimental data measured by the ATLAS Collaboration in pp collisions at center-of-mass energy √s = 2.76 TeV and in Pb-Pb collisions at center-of-mass energy per nucleon pair √sNN = 2.76 TeV. Based on the parameter values extracted from p T and η or y spectra, the event patterns or particle scatter plots in three-dimensional velocity and momentum spaces are obtained.