Speaker
Description
We present recent STAR measurements of the newly proposed radial flow fluctuation coefficient, $v_{0}(p_{T})$, for identified hadrons in heavy-ion collisions at RHIC. As a direct probe of the isotropic component of collective expansion, $v_{0}(p_{T})$ is uniquely sensitive to both the strength and event-by-event fluctuations of radial flow, offering new constraints on the initial-state geometry and transport properties of the created medium. The analysis encompasses both top RHIC energies and the full Beam Energy Scan (BES) program, covering $\sqrt{s_{NN}} = 11.5$ - $200$ GeV.
Using the STAR detector's large-acceptance dataset, we report the first systematic measurements of $v_{0}(p_{T})$ for a comprehensive set of identified hadrons, including $\pi^{\pm}$, $K^{\pm}$, $p$, $\bar{p}$, $\Lambda$, $\bar{\Lambda}$, $K^{0}_{S}$, $\Xi^{-}$, $\bar{\Xi}^{+}$, and $\phi$ mesons. The mass ordering of $v_{0}(p_{T})$ is investigated, and its Number-of-Constituent-Quark (NCQ) scaling is tested to examine whether radial flow, similar to elliptic flow, originates from partonic degrees of freedom. The energy dependence of $v_{0}(p_{T})$ is further scrutinized to map the evolution of collective dynamics across the QCD phase transition region. Comparisons with hydrodynamic and transport models provide stringent tests of theoretical descriptions and shed new light on the development of radial flow and its fluctuations as a function of collision energy.
| Academic Status | I am a Ph.D. student |
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