J/ψ production via fragmentation at HERA

We compute the contributions to large-pTJ/ψ production at DHEA coming from fragmentation of gluons and charm quarks. We find that the charm quark fragmentation contribution dominates over the direct production of J/ψ via photongluon fusion at large-pT, while the gluon fragmentation is negligibly small over the whole range of pT. An experimental study of pT distributions of J/ψ at HERA will providea direct probe of the charm quark fragmentation functions