Exclusive<i>J</i>/ψ and ψ(2<i>S</i>) production in<i>pp</i>collisions at $\protect \sqrt{s} = 7$ TeV

Abstract

Exclusive J/ and (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