Contribution of Linearly Polarised Gluons in Charmonium Production within the Soft Gluon Resummation Approach

In this article, the soft gluon resummation approach is used for modelling transverse-momentum dependent parton distributions. The transverse-momentum dependent factorisation allows to get access both to unpolarised parton distribution functions and to the Boer–Mulders functions which describe linearly polarised partons in unpolarised protons. The estimation for ratio of contributions of Boer–Mulders and unpolarised parton distributions for charmonium production in a range of center-of-mass energies of initial protons $$\\sqrt s $$ is made. The nonrelativistic QCD is used as a hadronisation model.