Speaker
Description
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 this talk, we overview recent jet substructure measurements in proton--proton and Pb--Pb collisions with ALICE.
In heavy-ion collisions, these include subjet fragmentation, $N$-subjettiness, the groomed jet momentum fraction, $z_g$, and the groomed jet radius, $\theta_g \equiv R_g/R$. By correcting these measurements for the large heavy-ion underlying event, and by selecting observables that are calculable in proton-proton collisions, these measurements allow direct comparison to theoretical models and begin to establish a phenomenological picture of the physics underlying jet quenching.
In proton--proton collisions, a new measurement of the primary Lund plane density for inclusive charged-particle jets in the transverse momentum range of $20 \leq p_{\rm{T,jet}}^{\rm ch} \leq 120$ GeV$/c$ with the ALICE detector will be presented. This is the first measurement of the Lund plane density in an intermediate jet $p_{\rm T}$ range where hadronization and underlying event effects play a dominant role. In addition to the Lund jet plane, new ALICE measurements of generalized angularities of groomed and inclusive jets, jet axis differences, and dynamically groomed jets will be discussed.
