# Event multiplicity, transverse momentum and energy dependence of charged particle production, and system thermodynamics in $pp$ collisions at the Large Hadron Collider

## TL;DR

This study analyzes charged particle production in proton-proton collisions at LHC energies using Tsallis and BGBW models, revealing insights into system thermodynamics and freeze-out parameters across different energies and multiplicities.

## Contribution

It introduces a thermodynamically consistent Tsallis distribution and evaluates the applicability of the BGBW model to $pp$ collision data at multiple energies and multiplicity classes.

## Key findings

- Tsallis distribution provides a better fit to the entire transverse momentum spectra.
- BGBW model effectively describes the bulk particle spectra.
- Radial flow remains nearly constant across energies and multiplicities.

## Abstract

In the present work, we study the recent collision energy and multiplicity dependence of the charged particle transverse momentum spectra as measured by the ALICE collaboration in $pp$ collisions at $\sqrt{s}$ = 5.02 and 13 TeV using the non-extensive Tsallis distribution and the Boltzmann-Gibbs Blast Wave (BGBW) model. A thermodynamically consistent form of the Tsallis distribution is used to extract the kinetic freeze-out parameters from the transverse momentum spectra of charged particles at mid-rapidity. In addition, a comprehensive study of fitting range dependence of transverse momentum spectra on the freeze-out parameters is done using Tsallis statistics. The applicability of BGBW model is verified by fitting the transverse momentum spectra of the bulk part ($\sim 2.5~ {\rm GeV}/c$)for both 5.02 and 13 TeV energies and also in different multiplicity classes. The radial flow, $<\beta>$ is almost independent of collision energy and multiplicity whereas the behavior of kinetic freeze-out temperature significantly depends on multiplicity classes. It is found that the Tsallis distribution generally leads to a better description for the complete transverse momentum spectra whereas the BGBW model explains the bulk part of the system.