Speaker
Description
Radial flow and anisotropic flow are key observables used to study the expansion dynamics of the quark-gluon plasma (QGP). While anisotropic flow has been extensively explored, the collective nature of radial flow has remained less understood. This talk presents the first measurement of transverse momentum ($p_{\mathrm{T}}$) dependence of radial flow fluctuations, $v_0(p_{\mathrm{T}})$, over $0.5 < p_{\mathrm{T}} < 10$ GeV in Pb+Pb collisions at $\sqrt{s_{\mathrm{NN}}} = 5.02$ TeV.
These measurements reveal three key features that establish the collective nature of radial flow: (i) long-range correlations in pseudorapidity, (ii) factorization in $p_{\mathrm{T}}$, and (iii) a centrality-independent shape in $p_{\mathrm{T}}$. The observed patterns provide new experimental constraints on the origin and fluctuations of radial flow. A comparison with hydrodynamic models demonstrates the sensitivity of $v_0(p_{\mathrm{T}})$ to bulk viscosity, offering a novel probe of QGP transport properties. These results introduce a new and powerful tool for investigating the collective dynamics of heavy-ion collisions, providing fresh insights into the fundamental properties of the QGP.
| Category | Experiment |
|---|---|
| Collaboration (if applicable) | ATLAS Collaboration |
