Updated measurements of exclusiveJ/ψ and ψ(2S) production cross-sections inppcollisions at $\sqrt{s}=7$ TeV

The differential cross-section as a function of rapidity has been measured for the exclusive production of J/ψ and ψ(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{equation*} \begin{array}{rl}\sigma _{pp\rightarrow {J /\psi } \rightarrow {\mu ^+}{\mu ^-}}(2.0<\eta _{\mu ^\pm }<4.5)=&291\pm 7\pm 19\ \rm pb,\\ \sigma _{pp\rightarrow \psi {(2{\rm S})} \rightarrow {\mu ^+}{\mu ^-}}(2.0<\eta _{\mu ^\pm }<4.5)=&6.5\pm 0.9\pm 0.4\ \rm pb,\\ \end{array} \end{equation*} 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.