Abstract
We revisit the description of pion production in proton-proton collisions in the light of the very precise data taken at the Large Hadron Collider (LHC) over the past decade. First attempts to include LHC results in next-to-leading order global QCD analyses of parton-to-pion fragmentation functions insinuated some conflict between data sets at different center-of-mass system energies. We show that the data can be well described within their uncertainties by a consistent set of pion fragmentation functions once the theoretical scale dependence is taken into account in the global QCD analysis.
Highlights
Pions are the most copiously produced particles in proton-proton collisions, and their different parton content and distinctive decay modes make them invaluable tools to analyze the breakdown of the colliding protons and the subsequent recombination of their constituents into new hadrons [1]
Fragmentation functions (FFs) play a cardinal role in the perturbative quantum chromodynamics (QCD) description of processes involving identified hadrons in the final state, as they connect the scattering of partons at short distance to the emerging hadrons observed in experiment [3]
We show the outcome of a similar fit with fixed κ 1⁄4 1 and a calculation based on the DSS set of FFs
Summary
Pions are the most copiously produced particles in proton-proton collisions, and their different parton content and distinctive decay modes make them invaluable tools to analyze the breakdown of the colliding protons and the subsequent recombination of their constituents into new hadrons [1]. A very conservative normalization uncertainty, comparable in size to the large factorization scale dependence exhibited by the protonproton cross sections, was introduced This strategy was unable to fully reconcile the pT dependence as predicted by the NLO approximation with the trend of the data. Since both ALICE and the RHIC experiments have delivered additional, remarkably precise PP data on neutral and charged pion production at different c.m.s. energies. Both ALICE and the RHIC experiments have delivered additional, remarkably precise PP data on neutral and charged pion production at different c.m.s. energies They confirmed their previous results and clearly showed that the shortcomings of the FF analysis of Ref. Estimates of the uncertainties inherited by any observable computed with our FFs can be obtained much more than in the Lagrange multipliers approach and without the complications related to choosing a particular tolerance criterion as in the Hessian framework
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
