Charged Particle Multiplicity Fluctuation in A-A Collisions at RHIC and LHC Energies Using Angantyr Model

Event-by-event fluctuations of the charged particle multiplicity are studiedfor a wide range of centralities for Au-Au collisions at √(s_NN) =200 GeV, Pb-Pb collisions at √(s_NN) = 2.76 TeV and 5.02 TeV using thePythia 8 Angantyr model. The centrality dependence of ω_ch observable,which quantifies the fluctuations in terms of scaled variance is studied fordifferent pseudorapidity ranges and has been compared with those obtained froma simple participant superposition model. The ω_ch was found to belower than the expectations from the participant model. The estimate would actlike a baseline for current and future measurements of event-by-eventfluctuations in the charged particle multiplicities in systems at LHC energieswhere no de-confined medium of quarks and gluons are formed.