Determining the jet transport coefficient q̂ from inclusive hadron suppression measurements using Bayesian parameter estimation

Abstract

We report a new determination of q̂, the jet transport coefficient of the quark-gluon plasma. We use the JETSCAPE framework, which incorporates a novel multistage theoretical approach to in-medium jet evolution and Bayesian inference for parameter extraction. The calculations, based on the Matter and Lbt jet quenching models, are compared to experimental measurements of inclusive hadron suppression in Au+Au collisions at the BNL Relativistic Heavy Ion Collider (RHIC) and Pb+Pb collisions at the CERN Large Hadron Collider (LHC). The correlation of experimental systematic uncertainties is accounted for in the parameter extraction. The functional dependence of q̂ on jet energy or virtuality and medium temperature is based on a perturbative picture of in-medium scattering, with components reflecting the different regimes of applicability of Matter and Lbt. In the multistage approach, the switch between Matter and Lbt is governed by a virtuality scale Q0. Comparison of the posterior model predictions to the RHIC and LHC hadron suppression data shows reasonable agreement, with moderate tension in limited regions of phase space. The distribution of q̂/T3 extracted from the posterior distributions exhibits weak dependence on jet momentum and medium temperature T, with 90% credible region (CR) depending on the specific choice of model configuration. The choice of Matter+Lbt, with switching at virtuality Q0, has 90% CR of 2<q̂/T3<4 for pT,jet>40 GeV/c. The value of Q0, determined here for the first time, is in the range 2.0–2.7 GeV.9 MoreReceived 23 February 2021Accepted 21 July 2021DOI:https://doi.org/10.1103/PhysRevC.104.024905©2021 American Physical SocietyPhysics Subject Headings (PhySH)Research AreasHydrodynamic modelsJets & heavy flavor physicsParticle & resonance productionRelativistic heavy-ion collisionsTechniquesBayesian methodsNuclear Physics