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

Abstract

Event-by-event mean transverse momentum fluctuations ($⟨p_{\mathrm{T}}⟩$) 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 $⟨p_{\mathrm{T}}⟩$ fluctuations in \auau collisions at $\sqrt{{\mathrm{s}}_{\mathrm{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 $⟨p_{\mathrm{T}}⟩$ 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.

Comments: 9 pages, 8 figures