Extracting Kinetic Freeze-out Properties in High Energy Collisions Using a Multi-source Thermal Model

TL;DR

This paper models the transverse momentum spectra of various hadrons in high-energy collisions using a multi-source thermal approach at the partonic level, fitting experimental data to extract freeze-out properties.

Contribution

It introduces a multi-source thermal model at the partonic level to analyze $p_T$ spectra, incorporating multiple distributions and sources to better understand kinetic freeze-out in high-energy collisions.

Findings

Successfully fits experimental $p_T$ spectra from PHENIX and STAR.

Extracts kinetic freeze-out temperature and transverse flow velocity.

Provides a baseline for future experimental and simulation studies.

Abstract

We study the transverse momentum ($p_T$) spectra of neutral pions and identified charged hadrons produced in proton--proton ($pp$), deuteron--gold ($d$--Au), and gold--gold (Au--Au) collisions at the center of mass energy $\sqrt{s_{NN}}=200$ GeV. The study is made in the framework of a multi-source thermal model used in the partonic level. It is assumed that the contribution to the $p_T$-value of any hadron comes from two or three partons with an isotropic distribution of the azimuthal angle. The contribution of each parton to the $p_T$-value of a given hadron is assumed to obey any one of the standard (Maxwell-Boltzmann, Fermi-Dirac, and Bose-Einstein) distributions with the kinetic freeze-out temperature and average transverse flow velocity. The $p_T$-spectra of the final-state hadrons can be fitted by the superposition of two or three components. The results obtained from our Monte Carlo method are used to fit the experimental results of the PHENIX and STAR Collaborations. The results of present work serve as a suitable reference baseline for other experiments and simulation studies.