Orateur
Description
The Lund jet plane is a jet substructure tool introduced to understand the radiation pattern of jets by organizing hadrons into a hierarchical tree of emissions using the Cambridge/Aachen clustering algorithm. The primary LJP, the first triangular leaf of Lund diagrams, is well understood analytically, and measurements at the LHC show how it can be used to constrain parton showers and hadronization models in a factorized way. We propose to extend the exploration of the Lund jet tree by turning to its secondary leaves, the secondary Lund jet planes, for further QCD measurements. If the respective primary Lund emission is chosen judiciously, such that it corresponds to the first branching in the jet shower, one can constrain the modeling of gluon-initiated jet showers independently of the quark/gluon jet fraction in the jet sample. We illustrate how one could use such a sample of gluon-rich jet radiation for an extraction of $\alpha_\mathrm{S}(m_\mathrm{Z})$ using a Lund-based multiplicity observable recently introduced in the literature.
