Substructures of heavy flavor jets in $pp$ and PbPb collisions at $\sqrt{s}$ = 5.02 TeV

TL;DR

This paper predicts and investigates the substructure of heavy flavor jets in proton-proton and lead-lead collisions at 5.02 TeV, revealing how mass and medium effects influence jet splitting characteristics.

Contribution

It provides the first detailed analysis of groomed jet substructure for heavy flavor jets in both $pp$ and PbPb collisions, highlighting mass and medium effects on jet splitting.

Findings

Heavy flavor jets have less momentum-balanced splittings than inclusive jets in $pp$ collisions.

In PbPb collisions, jet quenching suppresses balanced splittings and enhances large-angle splittings.

Heavy flavor jets show different modifications in $z_g$ and $R_g$ due to jet-medium interactions.

Abstract

Groomed jet substructure measurements, the momentum splitting fraction $z_g$ and the groomed jet radius $R_g$, of inclusive, D$^0$-tagged and B$^0$-tagged jets in $pp$ and central PbPb collisions at $\sqrt{s}=5.02$ TeV are predicted and investigated. Charged jets are constrained in a relatively low transverse momentum interval 15 $\leq p_{\rm T}^{\rm jet\ ch} <$ 30 GeV/$c$ where the QCD emissions are sensitive to mass effects. In $pp$ collisions, heavy flavor jets have less momentum-balanced splittings than inclusive jets and the larger quark mass is, the less momentum-balanced splittings are. B$^0$-tagged jets distribute at lager $R_g$ than both D$^0$-tagged and inclusive jets, while D$^0$-tagged jets distribute at smaller $R_g$ than inclusive jets. That can be explained by the competition between parton mass effects and flavour effects on splitting-angle distributions. In $A$+$A$ collisions, jet quenching effects further suppress the momentum-balanced splittings and enhance the large-angle splittings. Heavy flavor jets suffer more $z_g$ and less $R_g$ modifications due to jet-medium interactions. The mass hierarchy in $z_g$ of inclusive, D$^0$-tagged, B$^0$-tagged jets and competition between mass effects and Casimir colour factors in $R_g$ can also be observed in PbPb collisions.