LHC data challenges the contemporary parton-to-hadron fragmentation functions

TL;DR

This paper examines high-pT charged-particle production at the LHC, revealing that current theoretical models with existing fragmentation functions significantly overestimate experimental results, mainly due to overly hard gluon-to-hadron fragmentation functions.

Contribution

It highlights the discrepancy between experimental data and NLO QCD predictions, emphasizing the need to revise gluon-to-hadron fragmentation functions.

Findings

Most theoretical predictions overpredict measured cross sections

The discrepancy is mainly due to too hard gluon-to-hadron fragmentation functions

Scale variations and PDF errors do not resolve the overprediction

Abstract

We discuss the inclusive high-pT charged-particle production in proton-proton collisions at the LHC. The experimental data are compared to the NLO perturbative QCD calculations employing various sets of parton-to-hadron fragmentation functions. Most of the theoretical predictions are found to disastrously overpredict the measured cross sections, even if the scale variations and PDF errors are accounted for. The problem appears to arise from the presently too hard gluon-to-hadron fragmentation functions.