Measurement of ψ(2S) meson production in pp collisions at √s=7\ TeV

The differential cross-section for the inclusive production of (2S) mesons in pp collisions at s = 7 TeV has been measured with the LHCb detector. The data sample corresponds to an integrated luminosity of 36 pb -1 . The (2S) mesons are reconstructed in the decay channels (2S) + -and (2S) J / + -, with the J / meson decaying into two muons. Results are presented both for promptly produced (2S) mesons and for those originating from b-hadron decays. In the kinematic range p T ((2S)) 16 GeV/c and 2 < y((2S)) 4.5 we measure prompt (2S) = 1.44 0.01 (stat) 0.12 (syst) +0.20 -0.40 (pol) b, b (2S) = 0.25 0.01 (stat) 0.02 (syst) b, where the last uncertainty on the prompt cross-section is due to the unknown (2S) polarization. Recent QCD calculations are found to be in good agreement with our measurements. Combining the present result with the LHCb J / measurements we determine the inclusive branching fraction