EUROPEAN ORGANIZATION FOR NUCLEAR RESEARCH (CERN) CERN-PH-EP-2014-178

Study of χb meson production in pp collisions at s = 7 and 8 TeV and observation of the decay χb(3P) → Υ(3S)γ The LHCb collaboration† A study of χb meson production at LHCb is performed on proton-proton collision data, corresponding to 3.0 fb−1 of integrated luminosity collected at centre-of-mass energies s = 7 and 8 TeV. The fraction of Υ(nS) mesons originating from χb decays is measured as a function of the Υ transverse momentum in the rapidity range 2.0 < yΥ < 4.5. The radiative transition of the χb(3P) meson to Υ(3S) is observed for the first time. The χb1(3P) mass is determined to be mχb1(3P) = 10 511.3 ± 1.7 ± 2.5 MeV/c2, where the first uncertainty is statistical and the second is systematic. Submitted to Eur. Phys. J. C c © CERN on behalf of the LHCb collaboration, license CC-BY-4.0. †Authors are listed at the end of this paper. a