Charmonium Production

الأصل · EN

Theoretical analyses of the results on quarkonium production at large transverse momentum (pₜ) in p p collisions, at the Tevatron have revealed two novel features of the physics of quarkonium production: 1) the contribution of fragmentation of gluons and charm quarks to the cross-section at large pₜ, and 2) the importance of colour octet components of the quarkonium wave-function. I discuss the theoretical developments which have contributed to a reasonably consistent picture of quarkonium production at the Tevatron, and discuss large-pₜ J/ψ production at HERA and at LHC as important tests of the fragmentation picture. I also discuss our recent analysis of J/ψ production cross-sections at fixed-target energies, where we find that the energy dependence of the pₜ-integrated cross-sections for both pp and π- - p collisions is reasonably well reproduced, when the colour-octet components are included.