π0 and η meson production in proton-proton collisions at √s=8 TeV

Abstract

An invariant differential cross section measure- ment of inclusive π 0 and η meson production at mid-rapidity in pp collisions at √s = 8 TeV was carried out by the ALICE experiment at the LHC. The spectra of π0 and η mesons were measured in transverse momentum ranges of 0.3 < pT < 35GeV/cand0.5 < pT < 35GeV/c, respectively. Next-to-leading order perturbative QCD cal- culations using fragmentation functions DSS14 for the π0 and AESSS for the η overestimate the cross sections of both neutral mesons, although such calculations agree with the measured η/π0 ratio within uncertainties. The results were also compared with PYTHIA 8.2 predictions for which the Monash 2013 tune yields the best agreement with the mea- sured neutral meson spectra. The measurements confirm a universal behavior of the η/π 0 ratio seen for NA27, PHENIX and ALICE data for pp collisions from √s = 27.5 GeV to √s = 8 TeV within experimental uncertainties. A rela- tion between the π0 and η production cross sections for pp collisions at √s = 8 TeV is given by m T scaling for pT > 3.5 GeV/c. However, a deviation from this empir- ical scaling rule is observed for transverse momenta below p T < 3.5 GeV/c in the η/π 0 ratio with a significance of 6.2σ .