Energy dependence of transverse momentum fluctuations in Au+Au collisions from a multiphase transport model

TL;DR

This study investigates how transverse momentum fluctuations in gold-gold collisions vary with energy and centrality using an improved transport model, revealing deviations from simple scaling and differences between baryons and mesons.

Contribution

It provides a systematic analysis of $ ext{p}_ ext{T}$ fluctuations across energies and centralities with an improved model, highlighting deviations from scaling laws and particle type differences.

Findings

Scaled cumulants align with experimental trends.

Short-range correlations are slightly suppressed with a two-subevent method.

Baryons show more pronounced fluctuations than mesons.

Abstract

Event-by-event mean transverse momentum fluctuations ($\langle p_\mathrm{T}\rangle$) serve as a sensitive probe of initial state overlap geometry and energy density fluctuations in relativistic heavy-ion collisions. We present a systematic investigation of $\langle p_\mathrm{T}\rangle$ fluctuations in \auau collisions at $\mathrm{\sqrt{s_{NN}}} =$3.0-19.6 GeV, examining their centrality and energy dependence with the framework of an improved multiphase transport (AMPT) model. The centrality dependence of the $p_\mathrm{T}$ cumulants up to fourth order deviates significantly from simple powering-law scaling. Scaled cumulants are performed, with variances aligning well with the trends observed in the experimental data. Employing a two-subevent method, short-range correlations are slightly suppressed compared to the standard approach. Furthermore, baryons exhibit more pronounced $\langle p_\mathrm{T}\rangle$ fluctuations than mesons, potentially attributable to the effect of radial flow. These results provide referenced insights into the role of initial state fluctuations across different energies in heavy-ion collisions.