Measurements of azimuthal anisotropy of nonprompt D$^0$ mesons in PbPb collisions at $\sqrt{s_\mathrm{NN}}$ = 5.02 TeV

Measurements of the elliptic ($ v_{2} $) and triangular ($ v_{3} $) azimuthal anisotropy coefficients are presented for D$^{0} $ mesons produced in b hadron decays (nonprompt D$^{0} $ mesons) in lead-lead collisions at $ \sqrt{\smash[b]{s_{_{\mathrm{NN}}}}}= $ 5.02 TeV. The results are compared with previously published charm meson anisotropies measured using prompt D$^{0} $ mesons. The data were collected with the CMS detector in 2018 with an integrated luminosity of 0.58 nb$^{-1}$. Azimuthal anisotropy is sensitive to the interactions of quarks with the hot and dense medium created in heavy ion collisions. Comparing results for prompt and nonprompt D$^{0} $ mesons can assist in understanding the mass dependence of these interactions. The nonprompt results show lower magnitudes of $ v_{2} $ and $ v_{3} $ and weaker dependences on the meson transverse momentum and collision centrality than those found for prompt D$^{0} $ mesons. By comparing to theoretical predictions, the results imply that there is a mass hierarchy of quark interactions with the medium.