Publications by Malcolm John


Central exclusive production of J/ψ and ψ(2S) mesons in pp collisions at s=13$$ \sqrt{s}=13 $$ TeV

Journal of High Energy Physics Springer Nature America, Inc (2018)

C Patrignani, A Pearce, A Pellegrino, G Penso, M Pepe Altarelli, P Perret, K Petridis, A Petrolini, A Petrov, T Tekampe, G Tellarini, F Teubert, E Thomas, J van Tilburg, MJ Tilley, L Tomassetti, DY Tou, E Tournefier, U Uwer, C Vacca, A Vagner, V Vagnoni, TA Verlage, M Vernet, M Vesterinen

© 2018, The Author(s). Measurements are reported of the central exclusive production of J/ψ and ψ(2S) mesons in pp collisions at a centre-of-mass energy of 13 TeV. Backgrounds are significantly 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 < η < 4.5, are measured to be σJ/ψ→μ+μ−=435±18±11±17pbσψ(2S)→μ+μ−=11.1±1.1±0.3±0.4pb. The first uncertainties are statistical, the second are systematic, and the third are due to the luminosity determination. The cross-sections are also measured differentially 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.[Figure not available: see fulltext.]


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