Measurement of J/Ψ production in pp collisions at √s=7 TeV

The production of J-1.5pt/-0.45ptψ mesons in proton–proton collisions at √s=7 ~TeV is studied with the LHCb detector at the LHC. The differential cross-section for prompt J-1.5pt/-0.45ptψ production is measured as a function of the J-1.5pt/-0.45ptψ transverse momentum pT and rapidity y in the fiducial region pT∈[0;14]~GeV-2mu/-1mu c and y∈[2.0;4.5]. The differential cross-section and fraction of J-1.5pt/-0.45ptψ from b-hadron decays are also measured in the same pT and y ranges. The analysis is based on a data sample corresponding to an integrated luminosity of 5.2 pb−1. The measured cross-sections integrated over the fiducial region are for prompt J-1.5pt/-0.45ptψ production and for J-1.5pt/-0.45ptψ from b-hadron decays, where the first uncertainty is statistical and the second systematic. The prompt J-1.5pt/-0.45ptψ production cross-section is obtained assuming no J-1.5pt/-0.45ptψ polarisation and the third error indicates the acceptance uncertainty due to this assumption.