Exclusive J/ψ and ψ(2S) production in pp collisions at √s=7 TeV

Exclusive J/psi and psi(2S) vector meson production has been observed in the dimuon channel using the LHCb detector. The cross-section times branching fractions to two muons with pseudorapidities between 2.0 and 4.5 are measured to be sigma(pp -> J/psi(->mu+mu-))(2.0 < eta(mu +/-) < 4.5) = 307 +/- 21 +/- 36 pb, sigma(pp ->psi(2S)(->mu+mu-))(2.0 < eta(mu +/-) < 4.5) = 7.8 +/- 1.3 +/- 1.0 pb, where the first uncertainties are statistical and the second are systematic. The measurements are found to be in good agreement with results from previous experiments and theoretical predictions. The J/psi photoproduction cross-section has been measured as a function of the photon-proton centre-of-mass energy. The results are consistent with measurements obtained at HERA and confirm a similar power law behaviour for the photoproduction cross-section.