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  • Letter
  • Open Access

Data-driven quark- and gluon-jet modification in heavy-ion collisions

Jasmine Brewer*, Jesse Thaler†, and Andrew P. Turner‡

  • Center for Theoretical Physics, Department of Physics, Massachusetts Institute of Technology, 77 Massachusetts Avenue, Cambridge, Massachusetts 02139, USA

  • *jtbrewer@mit.edu
  • †jthaler@mit.edu
  • ‡apturner@mit.edu
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Phys. Rev. C 103, L021901 – Published 26 February, 2021

DOI: https://doi.org/10.1103/PhysRevC.103.L021901

Abstract

Whether quark- and gluon-initiated jets are modified differently by the quark-gluon plasma produced in heavy-ion collisions is a long-standing question that has thus far eluded a definitive experimental answer. A crucial complication for quark-gluon discrimination in both proton-proton and heavy-ion collisions is that all measurements necessarily average over the (unknown) quark-gluon composition of a jet sample. In the heavy-ion context, the simultaneous modification of both the fractions and substructure of quark and gluon jets by the quark-gluon plasma further obscures the interpretation. Here, we demonstrate a fully data-driven method for separating quark and gluon contributions to jet observables using a statistical technique called topic modeling. Assuming that jet distributions are a mixture of underlying “quark-like” and “gluon-like” distributions, we show how to extract quark- and gluon-jet fractions and constituent multiplicity distributions as a function of the jet transverse momentum. This proof-of-concept study is based on proton-proton and heavy-ion collision events from the Monte Carlo event generator Jewel with statistics accessible in Run 4 of the Large Hadron Collider. These results suggest the potential for an experimental determination of quark- and gluon-jet modifications.

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Supplemental Material

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Phys. Rev. C 103, L021901– Published 26 February, 2021
  • Received 2 September 2020
  • Accepted 2 February 2021
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Published by the American Physical Society under the terms of the Creative Commons Attribution 4.0 International license. Further distribution of this work must maintain attribution to the author(s) and the published article's title, journal citation, and DOI. Funded by SCOAP3.

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