Constraining color-charge effects of partonic energy loss with jet axis-based inclusive jet substructure measurement

TL;DR

This paper uses jet axis decorrelation measurements in heavy-ion collisions to constrain how the color charge of quarks and gluons affects their energy loss in the quark-gluon plasma, providing new insights into jet quenching mechanisms.

Contribution

It introduces a novel method to constrain gluon jet fractions and energy loss differences using jet substructure observables and template fits, enhancing understanding of color-charge effects in jet quenching.

Findings

Gluon jet fractions in PbPb collisions are consistent with model predictions.

Estimated quark and gluon energy losses align with other inclusive observable-based models.

Jet axis decorrelation measurements can effectively constrain partonic energy loss mechanisms.

Abstract

This study investigates the color-charge dependence of parton energy loss in the quark-gluon plasma (QGP) medium and the associated relative modifications of quark and gluon jet fractions compared to vacuum, using jet axis decorrelation observables. Recent CMS jet axis decorrelation measurements in PbPb collisions at 5.02 TeV are interpreted using Pythia simulations with varied quark/gluon jet compositions and emulated color-charge dependent energy loss. A template-fit procedure is employed to estimate the limits on gluon jet fractions in the published CMS data and average shift in jet momentum due to quenching for quark- and gluon-initiated jets traversing the QGP. The extracted gluon jet fractions and the estimated quark and gluon energy losses based on this study of jet axis decorrelations are found to be consistent with other model calculations based on inclusive observables. This work illustrates the use of jet substructure measurements for providing constraints on the color-charge dependence of parton energy loss and offers valuable insights for jet quenching models.