Charm-quark collectivity from small to large systems with ALICE

In these proceedings, the elliptic flow ($v_2$) measurement of prompt charm hadrons in lead-lead (Pb-Pb) and oxygen-oxygen (OO) collisions at $\sqrt{s_{\mathrm{NN}}} = 5.36$ TeV, using the data collected during LHC Run 3 by the ALICE detector, is presented. The analysis is performed at midrapidity ($|y| < 0.8$) and hadronic decay channels are used to reconstruct the signal candidates. The $v_2$ coefficient is measured via the Scalar Product (SP) technique. The $v_2$ of prompt D$^0$, D$^+$, D$_\text{s}^+$ mesons, and $\Lambda_{\text{c}}^+$ baryons in semicentral Pb-Pb collisions is reported. These results achieve unprecedented precision and low-$p_{\text{T}}$ reach for the D mesons and highlight the first observation of the splitting of baryon and meson elliptic flow at intermediate $p_{\text{T}}$ in the charm sector. The prompt D-meson $v_2$ is also measured in peripheral Pb-Pb collisions and central OO collisions, probing the degree of thermal equilibration reached by charm quarks propagating in progressively smaller quark-gluon plasma media.