11th International Conference on Hard and Electromagnetic Probes of High-Energy Nuclear Collisions

Groomed jet substructure measurements, the momentum splitting fraction $z_g$ and the groomed jet radius $R_g$, for inclusive, D${}^0$-tagged and B${}^0$-tagged jets in $pp$ and central Pb+Pb collisions at $\sqrt{s}=5.02$ TeV are investigated. Theoretical results for light-quark initiated and gluon initiated jets are provided as references though experimentally indistinguishable for now. Charged jets are constrained in a relative low transverse momentum interval 15 $\le p_{\mathrm{T}}^{\mathrm{j}\mathrm{e}\mathrm{t}\mathrm{c}\mathrm{h}}<$ 30 GeV/$c$ where the QCD emissions are sensitive to mass effects. The mass hierarchy manifests in $z_g$ distributions in both parton showering and jet quenching indicating steeper splitting functions of heavier partons. The flavour differences induced by Casimir factors do not contribute to $z_g$ distributions. Balanced splittings are suppressed due to jet quenching effects. The competition between flavor effects and mass effects to emission-angle distributions is directly observed for the first time. In both $pp$ and Pb+Pb collisions, the mass hierarchy in $R_g$ of inclusive, D${}^0$-tagged and B${}^0$-tagged jets is broken due to contributions from gluon-initiated jets. $R_g$ shift to more broaden distributions due to medium-induced modifications.