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

• Published in: The journal of high energy physics Vol. 2018; no. 10; pp. 1 - 27
• Main Authors: The LHCb collaboration, R. Aaij, B. Adeva, M. Adinolfi, C. A. Aidala, Z. Ajaltouni, S. Akar, P. Albicocco, J. Albrecht, F. Alessio, M. Alexander, A. Alfonso Albero, S. Ali, G. Alkhazov, P. Alvarez Cartelle, A. A. Alves, S. Amato, S. Amerio, Y. Amhis, L. An, L. Anderlini, G. Andreassi, M. Andreotti, J. E. Andrews, R. B. Appleby, F. Archilli, P. d’Argent, J. Arnau Romeu, A. Artamonov, M. Artuso, K. Arzymatov, E. Aslanides, M. Atzeni, S. Bachmann, J. J. Back, S. Baker, V. Balagura, W. Baldini, A. Baranov, R. J. Barlow, S. Barsuk, W. Barter, F. Baryshnikov, V. Batozskaya, B. Batsukh, V. Battista, A. Bay, J. Beddow, F. Bedeschi, I. Bediaga, A. Beiter, L. J. Bel, N. Beliy, V. Bellee, N. Belloli, K. Belous, I. Belyaev, E. Ben-Haim, G. Bencivenni, S. Benson, S. Beranek, A. Berezhnoy, R. Bernet, D. Berninghoff, E. Bertholet, A. Bertolin, C. Betancourt, F. Betti, M. O. Bettler, M. van Beuzekom, Ia. Bezshyiko, S. Bifani, P. Billoir, A. Birnkraut, A. Bizzeti, M. Bjørn, T. Blake, F. Blanc, S. Blusk, D. Bobulska, V. Bocci, O. Boente Garcia, T. Boettcher, A. Bondar, N. Bondar, S. Borghi, M. Borisyak, M. Borsato, F. Bossu, M. Boubdir, T. J. V. Bowcock, C. Bozzi, S. Braun, M. Brodski, J. Brodzicka, D. Brundu, E. Buchanan, A. Buonaura, C. Burr, A. Bursche
• Format: Journal Article
• Language: English
• Published: SpringerOpen 01.10.2018
• Subjects: Charm physics; Forward physics; Hadron-Hadron scattering (experiments); Particle and resonance production; Quarkonium
• ISSN: 1029-8479
• DOI: 10.1007/JHEP10(2018)167

Abstract 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 σ J / ψ → μ + μ − = 435 ± 18 ± 11 ± 17 p b σ ψ 2 S → μ + μ − = 11.1 ± 1.1 ± 0.3 ± 0.4 p b . $$ \begin{array}{c}\hfill {\sigma}_{J/\psi \to {\mu}^{+}{\mu}^{-}} = 435 \pm 18 \pm 11 \pm 17\ \mathrm{p}\mathrm{b}\hfill \\ {}\hfill {\sigma}_{\psi (2S)\to {\mu}^{+}{\mu}^{-}} = 11.1 \pm 1.1 \pm 0.3 \pm 0.4\ \mathrm{p}\mathrm{b}.\hfill \end{array} $$ 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.