Measurement of ϒ production in pp collisions at √s = 2.76 TeV

The production of ϒ(1S), ϒ(2S) and ϒ(3S) mesons decaying into the dimuon final state is studied with the LHCb detector using a data sample corresponding to an integrated luminosity of 3.3pb−1 collected in proton–proton collisions at a centre-of-mass energy of √s = 2.76 TeV. The differential production cross-sections times dimuon branching fractions are measured as functions of the ϒ transverse momentum and rapidity, over the ranges pT < 15 GeV/c and 2.0 < y < 4.5. The total cross-sections in this kinematic region, assuming unpolarised production, aremeasured to be σ (pp → ϒ(1S)X) × B (ϒ(1S) → μ+ μ−) = 1.111 ± 0.043 ± 0.044 nb, σ (pp → ϒ(2S)X) × B (ϒ(2S)→μ+ μ−) = 0.264 ± 0.023 ± 0.011 nb, σ (pp → ϒ(3S)X) × B (ϒ(3S) → μ+ μ−) = 0.159 ± 0.020 ± 0.007 nb, where the first uncertainty is statistical and the second systematic. © 2014, CERN for the benefit of the LHCb collaboration.