J/ψProduction and Polarization within a Jet

Zhong-Bo Kang, Jian-Wei Qiu, Felix Ringer, Hongxi Xing, and Hong Zhang

Index: 10.1103/PhysRevLett.119.032001

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Abstract

We study the production and polarization of J/ψ mesons within a jet in proton-proton collisions at the LHC. We define the J/ψ-jet fragmentation function as a ratio of differential jet cross sections with and without the reconstructed J/ψ in the jet. We demonstrate that this is a very useful observable to help explore the J/ψ production mechanism, and to differentiate between different nonrelativistic QCD global fits based on inclusive J/ψ cross sections. Furthermore, we propose to measure the polarization of J/ψ mesons inside the jet, which can provide even more stringent constraints for the heavy quarkonium production mechanism.