Photoproduction Processes Of J/? In The Framework Of NLP Factorization

The production of heavy quarkonium from photoproduction processes in high ener-gy collisions is studied in this thesis.This thesis adopts the newly developed fragmentation function approach(or QCD factorization formalism)in recent years,and discusses the process of photoproduction of charmed quarkonium-J/? particles in proton-proton(p-p)deep inelastic scattering.The fragmentation function approach is developed based on the NRQCD theory,which performs the double-coefficient expansion of the generated cross section at as and 1/pT,forming the leading-power term of the partonic fragment and adding the next-to-leading-power term of heavy-quark pairs fragment.In this thesis,we calculated the heavy quarkoniyum production cross-section of photon-partonic scattering in two reaction channels ?+q?[QQ(k)]+q and ? + g?[QQ(K)]+g.We compared the leading-order cross-section of fragmentation approach with the cross-section of NRQCD theory in the ?+q?QQ(3S1[8])+q?J/? + X process,it is found that the contribution of the former is slightly larger than that of the latter,but the overall trend is similar.Then,we compared the cross-section of the photo-production of heavy quarkonium with the cross-section of the partonic-partonic part,and it is found that the photoproduction of heavy quarkonium is smaller than the one from partonic-partonic interactions.To conclude:the fragmentation functions approach can be used as a complement and supplement to the NRQCD theory,which can provide an idea for solving the problem of the next-to-leading-order excess problem.