Measurement of Non-prompt $\rm D^0$-meson Elliptic Flow in Pb-Pb Collisions at $\sqrt{s_{\rm NN}}$ = 5.02 TeV

TL;DR

This paper measures the elliptic flow of non-prompt D0 mesons from beauty-hadron decays in Pb-Pb collisions at 5.02 TeV, providing insights into beauty-quark interactions with the quark-gluon plasma.

Contribution

It presents the first measurement of non-prompt D0 meson elliptic flow in heavy-ion collisions, comparing it to prompt D mesons and theoretical models.

Findings

Non-prompt D0 v2 is positive with 2.7σ significance.

Non-prompt D0 v2 is lower than prompt D mesons with 3.2σ significance.

Results are consistent with beauty-quark transport models.

Abstract

The elliptic flow ($v_2$) of $\rm D^0$ mesons from beauty-hadron decays (non-prompt $\rm D^0$) was measured in midcentral (30-50%) Pb-Pb collisions at a centre-of-mass energy per nucleon pair $\sqrt{s_{\rm NN}}$ = 5.02 TeV with the ALICE detector at the LHC. The $\rm D^0$ mesons were reconstructed at midrapidity ($|y|<0.8$) from their hadronic decay $\mathrm{D^0 \to K^-\pi^+}$, in the transverse momentum interval $2 < p_{\rm T} < 12$ GeV/$c$. The result indicates a positive $v_2$ for non-prompt $\rm D^0$ mesons with a significance of 2.7$\sigma$. The non-prompt $\rm D^0$-meson $v_2$ is lower than that of prompt non-strange D mesons with 3.2$\sigma$ significance in $2 < p_{\rm T} < 8$ GeV/$c$, and compatible with the $v_2$ of beauty-decay electrons. Theoretical calculations of beauty-quark transport in a hydrodynamically expanding medium describe the measurement within uncertainties.