Intermittency and fractal behaviour of charged particles generated using EPOS4 and PYTHIA8 at LHC energies

Abstract

Large density fluctuations of charged particles are the promising signatures for exploring the QCD phase transition and critical point in heavy ion collisions. These fluctuations are expected to exhibit fractal and scale invariant behaviour, which is probed using intermittency methodology. Intermittency is the phenomenon of power law growth of the normalized factorial moments ($F_{\rm{q}}$) of the number density distributions over decreasing bin size. This is studied for the charged particles simulated using PYTHIAN and EPOS4 (UrQMD ON/OFF) for Pb Pb collisions at $\sqrt{s_{\text{NN}}}$ = 5.02 TeV. Scaling behaviour of $F_{\rm{q}}$ are studied as a function of phase space partitioning and second order moments to quantify the particle production nature within the default constraints of the two models. The scaling exponent related to the phase transition and parameters connected to fractal nature obtained for these models are also reported.