Confronting current NLO parton fragmentation functions with inclusive charged-particle spectra at hadron colliders

AbstractThe inclusive spectra of charged particles measured at high transverse momenta (pT≳2 GeV/c) in proton–proton and proton–antiproton collisions in the range of center-of-mass energies s=200–7000 GeV are compared with next-to-leading order perturbative QCD calculations using seven recent sets of parton-to-hadron fragmentation functions (FFs). Accounting for the uncertainties in the scale choices and in the parton distribution functions, we find that most of the theoretical predictions tend to overpredict the measured LHC and Tevatron cross sections by up to a factor of two. We identify the currently too-hard gluon-to-hadron FFs as the probable source of the problem, and justify the need to refit the FFs using the available LHC and Tevatron data in a region of transverse momenta, pT≳10 GeV/c, which is supposedly free from additional non-perturbative contributions and where the scale uncertainty is only modest