Measurement of ψ(2S) meson production in pp collisions at ... formula ...

摘要

The differential cross-section for the inclusive production of ψ(2S) mesons in pp collisions at 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 pT(ψ(2S))≤16 GeV/c and 2<y(ψ(2S))≤4.5 we measure 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 where the last uncertainty is due to the , and branching fraction uncertainties.