Investigating the Bulk Properties of Charged Particles in Different $η$ Bins Using a Modified Tsallis Model

Abstract

This paper presents a comprehensive analysis of the double-differential $p_T$ distributions of charged particles in twelve distinct pseudorapidity regions of equal width in $pp$ collisions at center-of-mass energies of 0.9, 2.36, and 7 TeV. Utilizing the modified Tsallis function with mean transverse flow velocity, our study demonstrates a very good agreement between experimental data and the model employed. The fit quality is consistently high across all $p_T$ ranges, as assessed by Data/Fit panels accompanying each plot. Extracted parameters, including kinetic freeze-out temperature ($T_0$), transverse flow velocity ($β_T$), non-extensivity parameter ($q$) and mean transverse momentum $\langle p_T \rangle$ dependencies are shown on pseudorapidity ($η$) and collision energy ($\sqrt{s}$). $T_0$, $β_T$ and $\langle p_T \rangle$ exhibit a decreasing trend with increasing $η$ due to lower in energy transfer along high $η$ regions, while they show a heightened sensitivity to $\sqrt{s}$. $q$ increases with $η$, indicating a closer thermal equilibrium in mid-$η$ particles. The paper also explores correlations among these parameters, emphasizing relationships between $T_0$, $β_T$, $q$ and $\langle p_T \rangle$. Our study provides valuable insights into the thermal and dynamic characteristics of high-energy proton-proton collisions, contributing to the broader understanding of the bulk properties of nuclear matter produced in these interactions.