On the Topic of Jets: Disentangling Quarks and Gluons at Colliders

TL;DR

This paper introduces jet topics, a novel framework inspired by topic modeling, to identify and extract quark and gluon jet distributions from collider data with minimal reliance on simulations.

Contribution

The paper presents a new application of topic modeling techniques to collider physics, enabling data-driven separation of quark and gluon jets from experimental data.

Findings

Successfully extracted quark and gluon distributions from simulated data.

Demonstrated the potential to determine jet fractions in mixed samples.

Proposed a method to predict jet topics from theoretical calculations.

Abstract

We introduce jet topics: a framework to identify underlying classes of jets from collider data. Because of a close mathematical relationship between distributions of observables in jets and emergent themes in sets of documents, we can apply recent techniques in "topic modeling" to extract jet topics from data with minimal or no input from simulation or theory. As a proof of concept with parton shower samples, we apply jet topics to determine separate quark and gluon jet distributions for constituent multiplicity. We also determine separate quark and gluon rapidity spectra from a mixed Z-plus-jet sample. While jet topics are defined directly from hadron-level multi-differential cross sections, one can also predict jet topics from first-principles theoretical calculations, with potential implications for how to define quark and gluon jets beyond leading-logarithmic accuracy. These investigations suggest that jet topics will be useful for extracting underlying jet distributions and fractions in a wide range of contexts at the Large Hadron Collider.