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Gong-Ming Yu [1] and Gao-Gao Zhao [2] and Zhen Bai [1] and Yan-Bing Cai [2] and Hai-Tao Yang [3] and Jian-Song Wang [1]

Academic Editor: Enrico Lunghi

1, CAS Key Laboratory of High Precision Nuclear Spectroscopy and Center for Nuclear Matter Science, Institute of Modern Physics, Chinese Academy of Sciences, Lanzhou 730000, China, cas.cn

2, Department of Physics, Yunnan University, Kunming 650091, China, ynu.edu.cn

3, School of Physics and Electronic Information Engineering, Zhaotong University, Zhaotong 657000, China, ztu.edu.cn

Received Aug 10, 2017; Revised Oct 29, 2017; Accepted Dec 7, 2017

This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. The publication of this article was funded by SCOAP 3 .

1. Introduction

Heavy quarkonium is a multiscale system which can probe all regimes of Quantum Chromodynamics (QCD) and present an ideal laboratory for testing the interplay between perturbative and nonperturbative QCD within a controlled environment. In recent years, many measurement reports have been published by ALICE collaboration [1, 2], CMS collaboration [3, 4], ATLAS collaboration [5, 6], and LHCb collaboration [7, 8] at the Large Hadron Collider (LHC) energies; several theoretical approaches have been proposed such as the color-singlet (CS) mechanism [9, 10], the color-octet (CO) mechanism [11, 12], the color evaporation mechanism [13, 14], the color-dipole mechanism [15–18], the mixed heavy-quark hybrids mechanism [19], the recombination mechanism [20–24], the photoproduction mechanism [25–31], the potential Nonrelativistic Quantum Chromodynamics (pNRQCD) approach [32–34], the transverse-momentum-dependent factorization approach [35], the transport approach [36–41], the kT-factorization approach [42–45], the fragmentation approach [46–52], and the Nonrelativistic Quantum Chromodynamics (NRQCD) approach [53–67]. Among them, the NRQCD approach, which takes into account contributions of color-singlet component and color-octet components with the nonperturbative long-distance matrix elements (LDME), is the most successful in phenomenological studies. The long-distance matrix elements are process-independent and can be classified in terms of the relative velocity for the heavy quarks in the bound state. But, the heavy quarkonium production mechanism is still not fully understood.

In this study, we extend the hard photoproduction mechanism [68] to the heavy quarkonium production and investigate the production of inclusive ηc,b meson in p-p and Pb-Pb...

  

  

       

 

  

    

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