Measurement of nonprompt and prompt D⁰ azimuthal anisotropy in Pb-Pb collisions at √S_NN = 5.02 TeV

Purdue University, USA

^* e-mail: mstojano@purdue.edu

Published online: 1 March 2023

Abstract

Heavy quarks are primarily produced via initial hard scatterings, and thus carry information about the early stages of the Quark-Gluon Plasma (QGP). Measurements of the azimuthal anisotropy of the final-state heavy flavor hadrons provide information about the initial collision geometry, its fluctuation, and more importantly, the mass dependence of energy loss in QGP. Due to the larger bottom quark mass as compared to the charm quark mass, separate measurements of charm and bottom hadron azimuthal anisotropy can shed new light on understanding the dependence of the heavy quark and medium interaction. Because of the high branching ratio and large D⁰ mass, measurements of D⁰ meson coming from bottom hadron decay (nonprompt D⁰) can cover a broad kinematic range and be a good proxy of the parent bottom hadrons results. In this talk, we report on the prompt D⁰ and the first nonprompt D⁰ measurements of the azimuthal anisotropy elliptic (v₂) and triangular (v₃) coefficients of nonprompt D⁰ in PbPb collisions at √S_NN = 5.02 TeV. The measurements are performed as functions of transverse momentum p_T, in three centrality classes, from central to midcentral collisions. Compared to the prompt D⁰ results, the nonprompt D⁰ v₂ flow coefficients are systematically lower but have a similar dependence on p_T and centrality. A non-zero v₃ coefficient of the nonprompt D⁰ is observed. The obtained results are compared with theoretical predictions. The comparison could provide new constraints on the theoretical description of the interaction between heavy quarks and the medium.