J/ψ production dynamics: event shape, multiplicity and rapidity dependence in proton+proton collisions at LHC energies using PYTHIA8

Abstract

High-multiplicity p + p collisions at the Large Hadron Collider energies have created special importance in view of the Underlying Event (UE) observables. The recent results of LHC such as long range angular correlation, flow like patterns, strangeness enhancement etc. in high multiplicity events are not yet completely understood. In the same direction, the understanding of multiplicity dependence of J/ψ production is highly necessary. In the present study, we have investigated the different trend of multiplicity dependence of J/ψ production at mid-rapidity and forward rapidity through the transverse spherocity analysis. Adding a new variable called transverse spherocity, which describes the event shape, helps to investigate the particle production by isolating the hard and the soft components of the particle production and the importance of jets in high-multiplicity pp collisions. Using this tool, one can extensively study the contribution of jets to the observed structure by separating the isotropic and jetty events from the minimumbias. We have analyzed the J/ψ production at the mid-rapidity and forward rapidities via dielectron and dimuon channels, respectively using 4C tuned PYTHIA8 event generator. The analysis has been performed in two different center-of-mass energies: √ s = 5.02 and 13 TeV, to see the energy dependence of jet contribution to the multiplicity dependence study of J/ψ production. Furthermore, we have studied the production dynamics through the dependence of thermodynamic parameters on event multiplicity and transverse spherocity.

Characterizing Proton-Proton Collisions at the Large Hadron Collider with Thermal Properties

“…In view of these, there is a need to have a deeper understanding of high-multiplicity pp events to have a better understanding of the produced systems, possible associated thermodynamics, particle production dynamics and freeze-out. There have been attempts to study these events using event topology, which separates jetty (pQCD based hard scattering events) from isotropic (dominated by soft processes) events [9][10][11][12][13][14]. Using the temperature, T and Tsallis non-equilibrium parameter, q, extracted from the p T spectra various thermodynamical quantities are estimated in order to characterize the system created in pp [15] and heavy-ion collisions [16].…”

Centrality and Transverse Spherocity Dependent Study of Charged-Particle Production in Xe–Xe Collisions at √SNN=5.44 TeV Using PYTHIA8 Angantyr and AMPT Models

“…9. 𝑝 𝑇 spectra of 𝜋 ± in the 𝑐𝑒𝑛𝑡𝑟𝑎𝑙𝑖𝑡𝑦 bin 0-10% bin for PYTHIA an event is higher, the probability of that the event will become isotropic is also higher [7,28,29]. Therefore, the differential study of the particle production as a function of the centrality and transverse spherocity classes has great importance to understand the particle production mechanism.…”

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

“…We use 8.235 version of PYTHIA [5], which includes multipartonic interaction (MPI). MPI is crucial to explain the underlying events, multiplicity distributions and charmonia production [31][32][33]. Also, this version includes color reconnection which mimics the flow-like effects in pp collisions.…”