Measurement of upsilon production in pp collisions at root s=7 TeV

LHCb collaboration

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The production of Gamma (1S), Gamma (2S) and Gamma (3S) mesons in proton-proton collisions at the centre-of-mass energy of root 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 Gamma mesons are reconstructed in the decay mode Gamma -> mu(+)mu(-) and the signal yields are extracted from a fit to the mu(+)mu(-) invariant mass distributions. The differential production cross-sections times dimuon branching fractions are measured as a function of the Gamma 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 besigma(pp -> Gamma (1S) X) x B(Gamma (1S) -> mu(+)mu(-))= 2.29+/-0.01+/-0.10(-0.37)(+0.19) nb,sigma(pp -> Gamma(2S) X x B(Gamma(2S) -> mu(+)mu(-))= 0.562+/-0.007+/-0.023(-0.092)(+0.048) nb,sigma(pp -> Gamma (3S) X) x B(Gamma (3S) -> mu(+)mu(-))= 0.283+/-0.005+/-0.012(-0.048)(+0.025) nb,where the first uncertainty is statistical, the second systematic and the third is due to the unknown polarisation of the three Gamma states.
Original languageEnglish
Article number2025
Number of pages12
JournalEuropean Physical Journal C
Issue number6
Publication statusPublished - 1 Jun 2012
Externally publishedYes


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