Comparing effective temperatures in standard and Tsallis distributions from transverse momentum spectra in small collision systems

Abstract

The transverse momentum ($p_T$) spectra of identified light charged hadrons, specifically bosons ($\pi^{\pm}$ and $K^{\pm}$) as well as fermions [$p(\bar p)$], produced in small collision systems, namely deuteron-gold (d+Au) and proton-proton (p+p) collisions at the top energy of the Relativistic Heavy Ion Collider (RHIC) with a center-of-mass energy of $\sqrt{s_{NN}}=200$ GeV, are investigated in this paper. In present study, d+Au collisions are categorized into three centrality classes: central (0--20\%), semi-central (20--40\%), and peripheral (40--100\%) collisions. Various types of distributions, including standard [Bose-Einstein (Fermi-Dirac) and Boltzmann] and Tsallis distributions, are employed to fit the same $p_T$ spectra to derive different effective temperatures denoted as $T_{eff}$. The results indicate that $T_{eff}$ values obtained from Bose-Einstein, Boltzmann, Fermi-Dirac, and Tsallis distributions exhibit systematically a decreasing trend. Meanwhile, these $T_{eff}$ values also show a decreasing trend with a decrease in collision centrality. Furthermore, based on the spectra of given particles, a perfect linear relationship is observed between different pairwise combinations of $T_{eff}$ derived from both Boltzmann and Bose-Einstein (Fermi-Dirac) distributions as well as between Tsallis and Bose-Einstein (Fermi-Dirac) distributions.