Charm quark and QGP interactions through the spectra and anisotropic flow of D⁰ over the widest p_T interval using event-shape engineering at CMS

Purdue University, West Lafayette, IN, USA

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Published online: 17 April 2026

Abstract

The charm quark is formed almost exclusively during the initial stages of the collision, and a significant fraction of the charm quarks fragment into the D⁰ meson, the lightest open-charm hadron. We can gain insights into the interactions between the charm quark and the quark-gluon plasma (QGP medium by studying the production and the flow of the D⁰ meson in heavy-ion collisions. We study the effect of the initial shape of the collision system on the elliptic flow (v₂) of promptly produced D⁰ mesons in the p_T region 2-30 GeV/c using event-shape engineering (ESE) in PbPb collisions at 5.02 TeV at the CMS experiment. A correlation between the initial shape anisotropy and the D⁰ v₂ would suggest that the flow gets driven by the interactions between the charm quark and the QGP. Comparison with theoretical predictions allows us to unravel the mechanism behind the generation of v₂. We also study the anisotropic flow of nonprompt D⁰ produced due to the decay of the bottom quarks and the nuclear modification factor (R_AA) for prompt and nonprompt D⁰. These studies provide further insights into the QGP interactions of heavy quarks like charm and bottom in heavy-ion collisions in different p_T regions ranging from 1–40 GeV/c, the widest ever performed with ESE, and centralities between 0–50%.