Dynamic Jet Charge

TL;DR

The paper introduces the dynamic jet charge, a generalized jet charge definition that adapts to jet properties, enhancing discrimination between quark and gluon jets and revealing new features in jet structure analysis.

Contribution

It proposes a novel dynamic jet charge method with a variable weighting parameter, improving jet flavor discrimination and providing new insights into jet substructure.

Findings

Enhanced quark-gluon discrimination in proton-proton collisions.

Improved jet flavor identification in heavy ion collision simulations.

Distinct multi-peak features in dynamic jet charge distributions.

Abstract

We propose a modified definition of the jet charge, the "dynamic jet charge", where the constant jet momentum fraction weighting parameter, $\kappa$, in the standard jet charge definition is generalized to be a function of a dynamical property of the jet or the individual jet constituents. The dynamic jet charge can complement analyses based on the standard definition and give improved discrimination between quark and gluon initiated jets and between jets initiated by different quark flavors. We focus on the specific scenario where each hadron in the jet contributes to the dynamic jet charge with a $\kappa$-value dynamically determined by its jet momentum fraction. The corresponding dynamic jet charge distributions have qualitatively distinct features and are typically characterized by a multiple peak structure. For proton-proton collisions, compared to the standard jet charge, the dynamic jet charge gives significantly improved discrimination between quark and gluon initiated jets and comparable discrimination between $u$- and $d$-quark initiated jets. In Pythia simulations of heavy ion collisions, the dynamic jet charge is found to have higher jet discrimination power compared to the standard jet charge, remaining robust against the increased contamination from underlying event. We also present phenomenological applications of the dynamic jet charge to probe nuclear flavor structure.