Measurement of ψ(2 S) meson production in pp collisions at [Formula: see text]

Eur Phys J C Part Fields. 2012;72(8):2100. doi: 10.1140/epjc/s10052-012-2100-4. Epub 2012 Aug 10.

Abstract

The differential cross-section for the inclusive production of ψ(2S) mesons in pp collisions at [Formula: see text] 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 [Formula: see text] 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 [Formula: see text] where the last uncertainty is due to the [Formula: see text], [Formula: see text] and [Formula: see text] branching fraction uncertainties.