J/ψ production within a jet in high-energy proton-proton and nucleus-nucleus collisions

¹ Department of Physics, Hubei University, Wuhan 430062, China
² Key Laboratory of Atomic and Subatomic Structure and Quantum Control (MOE), Guangdong Basic Research Center of Excellence for Structure and Fundamental Interactions of Matter, Institute of Quantum Matter, South China Normal University, Guangzhou 510006, China
³ Guangdong-Hong Kong Joint Laboratory of Quantum Matter, Guangdong Provincial Key Laboratory of Nuclear Science, Southern Nuclear Science Computing Center, South China Normal University, Guangzhou 510006, China
⁴ Southern Center for Nuclear-Science Theory (SCNT), Institute of Modern Physics, Chinese Academy of Sciences, Huizhou 516000, China

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Published online: 5 November 2025

Abstract

We report a systematic study of J/ψ production within a jet in pp and its modification in heavy-ion collisions. Within the framework of leading power factorization formalism of nonrelativistic QCD, we calculate the jet fragmentation function for high-p_T J/ψ production in proton-proton collisions. The good agreements between theory and experimental data indicate that J/ψ production within a jet is dominated by gluon fragmentation. And then, we carry out the first theoretical investigation on the medium modification of J/ψ production within jets in heavy-ion collisions, using a linear Boltzmann transport model coupled with hydrodynamical evolution for the simulation of jet-medium interactions. The result reveals that the gluon energy loss is the driving force for the suppression of J/ψ production in jets. Furthermore, we make predictions for the dependence of R_AA on jet transverse momentum and jet radius.