“Elucidating QCD using charm-tagged jet substructure measurements with ALICE at the LHC”
In high-energy hadronic collisions, heavy quarks (charm and beauty), due to their large masses, are predominantly produced through hard scattering processes during the early stages of the collisions. Their production is well described by perturbative quantum chromodynamics (pQCD) calculations. Jets, which are collimated sprays of particles originating from hard-scattered partons, are a crucial observable in high-energy particle physics as they provide direct access to the kinematics of the parton initiating the shower. QCD predicts that jet radiation patterns depend on the mass and color charge of the initiating parton.
This talk presents three key charm-tagged jet (reconstructed D⁰-meson) measurements from the ALICE experiment, starting with angular differences between jet axes and advancing to more differential observables, such as jet angularities and higher-order energy-energy correlators (EECs), which provide increasingly detailed insights into charm jet shower properties.
- Jet axes differences measured with three definitions, each with varying sensitivity to wide-angle soft radiation, systematically exploring radiation patterns off charm quarks.
- Jet angularity, which characterizes the weighted angular distribution of a jet’s constituent transverse momentum, is a powerful observable that further probes the parton shower by distinguishing between mass and Casimir effects through the exploitation of the angular exponent
- Expanding this differential analysis to include EECs, defined as the energy-weighted cross section of particle pairs within jets, reveals the detailed structure of QCD radiation from heavy quarks, allowing for a distinction between perturbative and non-perturbative effects. This approach offers crucial new insights into hadronization processes.
Comparisons to inclusive jets (gluon-dominated) and various MC event generators reveal sensitivity to both flavor-dependent effects in the parton shower and hadronization mechanisms. Moreover, comparisons with next-to-leading order calculations emphasize the need for improved theoretical modeling of heavy quark jets and provide critical insights into the parton-to-hadron transition in QCD.
Host: Isaac Mooney