The differential cross-section for the inclusive production of ψ(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 ψ(2S) mesons are reconstructed in the decay channels ψ(2S)→μ +μ - and ψ(2S)→J/ψπ +π -, with the J/ψ meson decaying into two muons. Results are presented both for promptly produced ψ(2S) mesons and for those originating from b-hadron decays. In the kinematic range p T(ψ(2S))≤16 GeV/c and 2<y(ψ(2S))≤4. 5 we measure σ prompt(ψ(2S)) = 1.44±0.01 (stat)±0.12 (syst) -0.40 0.20 (pol) μb, σ b(ψ(2S))= 0.25±0.01 (stat)±0.02 (syst) μb, where the last uncertainty on the prompt cross-section is due to the unknown ψ(2S) polarization. Recent QCD calculations are found to be in good agreement with our measurements. Combining the present result with the LHCb J/ψ measurements we determine the inclusive branching fraction B(b→ψ(2S)X) =(2.73±0.06 (stat)±0.16(syst)±0.24(BF))×10 -3, where the last uncertainty is due to the B(b→J/ψX), B(J/ψ→μ +μ -) and B(ψ(2S)→e +e -) branching fraction uncertainties. © 2012 CERN for the benefit of the LHCb collaboration.
Aaij, R., Abellan Beteta, C., Adeva, B., Adinolfi, M., Adrover, C., Affolder, A., et al. (2012). Measurement of ψ(2S) meson production in pp collisions at √s = 7 TeV. THE EUROPEAN PHYSICAL JOURNAL. C, PARTICLES AND FIELDS, 72(8), 1-12 [10.1140/epjc/s10052-012-2100-4].