Event Shape and Multiplicity Dependence of Freeze-Out Scenario and System Thermodynamics in Proton+Proton Collisions at s = 13 TeV Using PYTHIA8

Recent observations of QGP-like conditions in high-multiplicity pp collisions from ALICE experiment at the LHC warrant an
introspection whether to use pp collisions as a baseline measurement to characterize heavy-ion collisions for the possible
formation of a Quark-Gluon Plasma. A double differential study of the particle spectra and thermodynamics of the produced
system as a function of charged-particle multiplicity and transverse spherocity in pp collisions would shed light on the
underlying event dynamics. Transverse spherocity, one of the event shape observables, allows to separate the events in terms of
jetty and isotropic events. We analyse the identified particle transverse momentum (pT) spectra as a function of charged-particle
multiplicity and transverse spherocity using Tsallis nonextensive statistics and Boltzmann-Gibbs Blast-Wave (BGBW) model in pp
collisions at ffiffi
s p = 13 TeV using PYTHIA8 event generator. The extracted parameters such as temperature (T), radial flow (β), and
nonextensive parameter (q) are shown as a function of charged-particle multiplicity for different spherocity classes. We observe
that the isotropic events approach thermal equilibrium while the jetty ones remain far from equilibrium. We argue that, while
studying the QGP-like conditions in small systems, one should separate the isotropic events from the spherocity-integrated events,
as the production dynamics are different.