Jet Charge with Global Event Shapes: Probing Quark Flavor Dynamics

TL;DR

This paper introduces a novel method to measure jet electric charge within global event shapes to investigate quark flavor dynamics in nucleons and hadronization, applicable to DIS processes and future collider experiments.

Contribution

It develops a factorization theorem for simultaneous measurements of 1-Jettiness and jet charge, including a new universal charged jet function for enhanced flavor analysis.

Findings

The 1-Jettiness jet charge observable can distinguish quark flavors in nucleon structure.

Simulation shows sensitivity of the observable to quark flavor dynamics and hadronization.

Method is compatible with existing HERA data and future EIC experiments.

Abstract

We propose measuring the jet electric charge of jet regions, defined within the framework of global event shapes, as a probe of quark flavor dynamics within the nucleon and the hadronization process. In particular, we consider a measurement of the jet region charge while simultaneously keeping track of the energy flow throughout the event, as characterized by the global event shape. As a concrete example, we focus on the measurement of the 1-Jettiness jet charge ($Q$), the jet charge of the jet region ($J$) defined within the framework of the 1-Jettiness global event shape ($\tau_1$) for the Deep Inelastic Scattering (DIS) process, $e^- + p \to e^- + J + X$, with unpolarized or longitudinally polarized protons. The 1-Jettiness distribution, binned according to jet charge, allows for enhanced quark flavor separation of the initial state unpolarized or polarized PDFs. On the other hand, the jet charge distribution binned by 1-Jettiness can serve as a probe of quark flavor dynamics in the final state hadronization process. We derive a factorization theorem for simultaneous measurements of $\tau_1$ and $Q$ in the resummation region, $\tau_1 \ll P_{J_T}$, where $P_{J_T}$ denotes the transverse momentum of the jet region. The factorization theorem contains a new universal charged jet function, generalizing the standard jet function to include a jet charge measurement. Therefore these universal functions can be extracted from a global analysis of N-jettiness and thrust at $e^+e^-$ colliders. We provide simulation studies to demonstrate the sensitivity of the 1-Jettiness jet charge observable to quark flavor dynamics in nucleon structure and explore the possibility of probing the final state hadronization process. This observable is well-suited for applications with existing HERA data and the future Electron-Ion Collider (EIC).