Investigating charm-quark dynamics in the QGP via the charm-hadron elliptic flow in Pb-Pb collisions with ALICE

TL;DR

This paper reports precise measurements of charm-hadron elliptic flow in Pb-Pb collisions at the LHC, revealing differences between baryons and mesons and providing new insights into charm-quark dynamics in the quark-gluon plasma.

Contribution

First measurement of elliptic flow for prompt and non-prompt charm hadrons, including the $ ext{Lambda}_c^+$ baryon, with unprecedented precision and low-$p_T$ reach.

Findings

Observation of baryon-meson elliptic flow splitting at intermediate $p_T$

Lower $v_2$ for non-prompt charm hadrons due to larger quark mass

Enhanced precision in charm-hadron flow measurements

Abstract

In these proceedings, the elliptic flow ($v_{2}$) measurement of prompt and non-prompt charm hadrons - originating respectively from the fragmentation of a charm quark and from the decay of hadrons with beauty-quark content - in Pb-Pb collisions at $\sqrt{s_{\mathrm{NN}}} = 5.36~\text{TeV}$, using the latest 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 prompt $v_{2}$ in semicentral collisions is reported for the $D^{0}$, $D^{+}$, $D_{s}^{+}$ mesons and, for the first time, for the $\Lambda_{c}^{+}$ baryon. These results achieve unprecedented precision and low-$p_{\mathrm{T}}$ reach for the D mesons and highlight the first observation of the splitting of baryon and meson elliptic flow at intermediate $p_{\mathrm{T}}$ in the charm sector. The $v_{2}$ is also measured for prompt $D^{0}$, $D^{+}$ and $D_{s}^{+}$ in peripheral collisions, offering new insights into the features of the fireball generated in ultrarelativistic heavy-ion collisions. Lower $v_{2}$ values are observed for non-prompt $D^{0}$ and $\Lambda_{c}^{+}$ hadrons in semicentral collisions, as expected from the larger beauty-quark mass.