The differential cross-section as a function of rapidity has been measured for the exclusive production of $J/psi$ and $psi(2S)$ mesons in proton-proton collisions at $sqrt{s}=7$ TeV, using data collected by the LHCb experiment, corresponding to an integrated luminosity of 930 pb$^{-1}$. The cross-sections times branching fractions to two muons having pseudorapidities between 2.0 and 4.5 are measured to be $$begin{array}{rl} sigma_{pprightarrow J/psirightarrow{mu^+}{mu^-}}(2.0<eta_{mu^pm }<4.5)=&291pm 7pm19 {rm pb}, sigma_{pprightarrowpsi(2S)rightarrow{mu^+}{mu^-}}(2.0<eta_{mu^pm}<4.5)=&6.5pm 0.9pm 0.4 {rm pb},end{array}$$ where the first uncertainty is statistical and the second is systematic. The measurements agree with next-to-leading order QCD predictions as well as with models that include saturation effects.
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