PT Journal AU LHCb Collaboration (Aaij, Rea Garcia Martin, LM Henry, L Martinez-Vidal, F Oyanguren, A Remon Alepuz, C Ruiz Vidal, J Sanchez Mayordomo, C TI Central exclusive production of J/psi and (2S) mesons in pp collisions at root s=13 TeV SO Journal of High Energy Physics JI J. High Energy Phys. PY 2018 BP 167 EP 27pp VL 10 IS 10 DI 10.1007/JHEP10(2018)167 LA English DE Charm physics; Forward physics; Hadron-Hadron scattering (experiments); Particle and resonance production; Quarkonium AB Measurements are reported of the central exclusive production of J= and ( 2 S) mesons in pp collisions at a centre- of- mass energy of 13 TeV. Backgrounds are signi fi cantly reduced compared to previous measurements made at lower energies through the use of new forward shower counters. The products of the cross- sections and the branching fractions for the decays to dimuons, where both muons are within the pseudorapidity range 2 : 0 < < 4 : 5, are measured to be The fi rst uncertainties are statistical, the second are systematic, and the third are due to the luminosity determination. The cross- sections are also measured di ff erentially for meson rapidities between 2.0 and 4.5. Good agreement is observed with theoretical predictions. Photoproduction cross- sections are derived and compared to previous experiments, and a deviation from a pure power- law extrapolation of lower energy data is observed. ER