System-size dependence of jet quenching from light to heavy-ion collisions at LHC

Abstract

Single inclusive hadron suppression in high-energy heavy-ion collisions provides a sensitive probe of parton energy loss and jet transport coefficient in quark-gluon plasma (QGP). System size dependence of jet quenching can provide further constraints on the dynamics of jet quenching and parton energy loss. Motivated by recent experiments on light-ion collisions at the Large Hadron Collider (LHC), we perform a systematic study of single-inclusive hadron suppression in O+O, Ne+Ne, Xe+Xe and Pb+Pb collisions at the LHC energies. The calculations are carried out within the next-to-leading-order perturbative QCD model, incorporating the nuclear modified initial-state parton distributions, final-state parton energy loss in the higher-twist approach and the temperature dependence of the jet transport coefficient $\hat{q}/T^3$ from the Bayesian analyses of previous experimental data at the Relativistic Heavy-ion Collider (RHIC) and LHC. Our model calculations can simultaneously describe the measured single-inclusive charged hadron $R_{AA}$ in O+O, Ne+Ne, Xe+Xe and Pb+Pb collisions over a broad range of event centralities and in the minimum-bias events. We further illustrate the system size dependence of jet quenching through the ratio $R_{\mathrm{NeNe}}/R_{\mathrm{OO}}$ and the modification factors $R_{AA}$ as a function of $⟨N_{\mathrm{coll}}⟩$ which follow a common behavior at fixed $p_{\mathrm{T}}$, indicating the formation of QGP even in the smallest collision systems.

arXiv comment6 pages, 5 figures