Measurement of ϒ production in pp collisions at √s =7 TeV

The production of Υ{hooked}(1S), Υ{hooked}(2S) and Υ{hooked}(3S) mesons in proton-proton collisions at the centre-of-mass energy of √ s = 7TeV is studied with the LHCb detector. The analysis is based on a data sample of 25 pb^-1 collected at the Large Hadron Collider. The Υ{hooked} mesons are reconstructed in the decay mode Υ{hooked}→μ⁺μ^- and the signal yields are extracted from a fit to the μ⁺μ^- invariant mass distributions. The differential production cross-sections times dimuon branching fractions are measured as a function of the Υ{hooked} transverse momentum p_T and rapidity y, over the range p_T<15 GeV/c and 2. 0<y<4. 5. The cross-sections times branching fractions, integrated over these kinematic ranges, are measured to be [Equation not available: see fulltext.] where the first uncertainty is statistical, the second systematic and the third is due to the unknown polarisation of the three Υ{hooked} states.