Non-Monotonicity of $p_{\mathrm{T}}$ Correlations in Au + Au Collisions at RHIC

Abstract

We report the first measurements of two-particle transverse momentum correlations for mid-rapidity charged particles in Au+Au collisions at $\sqrt{s_{\mathrm{NN}}}=$ 3.0, 3.2, 3.5, 3.9, 4.5, 5.2 and 7.7 GeV recorded by the STAR experiment. The results are compared with previous STAR measurements from the Beam Energy Scan Phase I (BES-I) and with transport model calculations. The measured two-particle $p_{\mathrm{T}}$ correlators exhibit an approximate power-law scaling with the number of participating nucleons ($N_{\mathrm{part}}$), consistent with expectations from an independent-source scenario. This scaling is least well described at the lowest collision energy, $\sqrt{s_{\mathrm{NN}}}=3.0$~GeV. Furthermore, a non-monotonic energy dependence of the $p_{\mathrm{T}}$ correlations is observed in central collisions, representing the first systematic observation of such behavior as a function of collision energy.

Strangeness in Quark Matter 2026 proceedings, 4 pages, 2 Figures

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