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

Abstract

The transverse momentum (pT) 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 pT 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 pT 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 TeV and in Pb–Pb collisions at center-of-mass energy per nucleon pair TeV. Based on the parameter values extracted from pT and η or y spectra, the event patterns or particle scatter plots in three-dimensional velocity and momentum spaces are obtained.