Energy dependence of J/ production in pp collisions from the PACIAE model

In this work we investigate the J/psi production in proton -proton collisions at the center -of -mass energy (./s) equal to 2.76, 5.02, 7, 8, and 13 TeV with the parton and hadron cascade model PACIAE 2.2a. It is based on PYTHIA but extended considering the partonic and hadronic rescatterings before and after hadronization, respectively. In the PYTHIA sector the J/psi production quantum chromodynamics processes are selected specially and a bias factor is proposed correspondingly. The calculated total cross sections, the transverse momentum differential, and the rapidity differential cross sections of J/psi in the forward rapidity region reproduce the corresponding experimental measurements reasonably well. In the mid -rapidity region, the double -differential cross sections at ./s = 5.02, 7, and 13 TeV are also in a good agreement with the experimental data. Moreover, we interpolate the double -differential cross section as well as the total cross section of J/psi in the mid -rapidity region at ./s = 8 TeV, which could be validated if the experimental data are available.