Impact of ηc Hadroproduction Data on Charmonium Production and Polarization within the Nonrelativistic QCD Framework

With the recent LHCb data on eta(c) production and based on heavy quark spin symmetry, we obtain the long-distance matrix elements for both eta(c) and J/psi productions, among which, the color-singlet one for eta(c) is obtained directly by the fit of experiment for the first time. Using our long-distance matrix elements, we can provide good description of the eta(c) and J/psi hadroproduction measurements. Our predictions on J/psi polarization are in good agreement with the LHCb data, explain most of the CMS data, and pass through the two sets of CDF measurements in the medium p(t) region. Considering all the possible uncertainties carefully, we obtained quite narrow bands of the J/psi polarization curves.