Deciphering QCD dynamics in small collision systems using event shape and final state multiplicity at the Large Hadron Collider

Abstract

The high-multiplicity pp collisions at the Large Hadron Collider energies with various heavyion-like signatures have warranted a deeper understanding of the underlying physics and particle production mechanisms. As an effort to have better understanding in this direction, we attempt to study the event shape and multiplicity dependence of specific heat capacity, conformal symmetry breaking measure (CSBM) and speed of sound in pp collisions at √ s = 13 TeV using PYTHIA8 event generator in Monash 2013 tune. The observables show a clear dependence on event multiplicity and event topology. A threshold in the particle production, dN ch /dη (10-20) in the final state multiplicity emerges out from the present study, confirming some of the earlier findings in this direction.