engleski

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

An invariant differential cross section measurement of inclusive π0 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 < 35 GeV/c and 0.5 < pT < 35 GeV/c, respectively. Next-to-leading order perturbative QCD calculations 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 measured neutral meson spectra. The measurements confirm a universal behavior of the η/π0 ratio seen for NA27, PHENIX and ALICE data for pp collisions from s√=27.5 GeV to s√=8 TeV within experimental uncertainties. A relation between the π0 and η production cross sections for pp collisions at √s=8 TeV is given by mT scaling for pT > 3.5 GeV/c. However, a deviation from this empirical scaling rule is observed for transverse momenta below pT < 3.5 GeV/c in the η/π0 ratio with a significance of 6.2σ.

Pi ; Eta ; Meson ; proton-proton ; 8 TeV

nije evidentirano