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

The production of (1S), (2S) and (3S) mesons in proton-proton collisions at the centre-of-mass energy of s = 7 TeV 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 mesons are reconstructed in the decay mode + -and the signal yields are extracted from a fit to the + -invariant mass distributions. The differential production cross-sections times dimuon branching fractions are measured as a function of the 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 pp (1S)X B (1S) + - = 2.29 0.01 0.10 +0.19 -0.37 nb, pp (2S)X B (2S) + - = 0.562 0.007 0.023 +0.048 -0.092 nb, pp (3S)X B (3S) + - = 0.283 0.005 0.012 +0.