Jet substructure measurements in heavy-ion collisions with ALICE

TL;DR

This paper presents new jet substructure measurements in heavy-ion collisions using ALICE, providing insights into jet quenching and the quark-gluon plasma through detailed observables like $z_g$, $θ_g$, and $N$-subjettiness.

Contribution

First fully corrected measurements of groomed jet observables in Pb-Pb collisions at 5.02 TeV, offering new constraints on jet quenching physics.

Findings

Measurements of groomed jet momentum splitting fraction $z_g$

Results on groomed jet radius $θ_g$ and $N$-subjettiness

Comparison with theoretical models to constrain jet quenching mechanisms

Abstract

Jet substructure, defined by observables constructed from the distribution of constituents within a jet, provides the versatility to tailor observables to specific regions of QCD radiation phase space. This flexibility provides exciting new opportunities to study jet quenching in heavy-ion collisions and to ultimately help reveal the nature of the quark-gluon plasma. The ALICE detector is particularly well-suited to jet substructure measurements in heavy-ion collisions due to its high-precision tracking system. In these proceedings, we report several new jet substructure measurements in Pb-Pb collisions at $\sqrt{s_{\mathrm{NN}}}=5.02$ TeV with ALICE. These include the first fully corrected measurements of the groomed jet momentum splitting fraction, $z_{\rm{g}}$, and the groomed jet radius, $\theta_{\rm{g}} \equiv R_{\rm{g}}/R$, as well as $N$-subjettiness and the fragmentation distribution of reclustered sub-jets. These measurements are compared to theoretical calculations and provide new constraints on the physics underlying jet quenching.