Updated measurements of exclusive J/ψ and ψ(2S) production cross-sections in pp collisions at s√=7 TeV

Abstract

The differential cross-section as a function of rapidity has been measured for the exclusive production of J/ψ and ψ(2S) mesons in proton–proton collisions at √s = 7 TeV, using data collected by the LHCb experiment, corresponding to an integrated luminosity of 930 pb−1. The cross-sections times branching fractions to two muons having pseudorapidities between 2.0 and 4.5 are measured to be σpp→J/ψ →μ+μ− (2.0 < ημ± < 4.5) = 291 ± 7 ± 19 pb, σpp→ψ(2S)→μ+μ− (2.0 < ημ± < 4.5) = 6.5 ± 0.9 ± 0.4 pb, where the first uncertainty is statistical and the second is systematic. The measurements agree with next-to-leading order QCD predictions as well as with models that include saturation effects.