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Gonzalez, J. Suarez; Bansal, S.; Cornelis, T.; De Wolf, E. A.; Keaveney, J.; Van Onsem, G. P.; Gay, A. P. R.; Popov, A.; Santaolalla, J.; Peltola, T.; Bloch, D.; Chierici, R.; Fan, J.; Ille, B.; Perieanu, A.; Olschewski, M.; Choudhury, S.; Pardos, C. Diez; Hempel, M.; Kieseler, J.; Cipriano, P. M. Ribeiro; Steinbrück, G.; Husemann, U.; Ujvari, B.; Sharan, M.; Gurtu, A.; Mohanty, G. B.; Felcini, M.; Iaselli, G.; Brigliadori, L.; Guiducci, L.; Marcellini, S.; Gerosa, R.; Dall’Osso, M.; Margoni, M.; Verdini, P. G.; Vernieri, C.; Maselli, S.; Solano, A.; Park, I. C.; Choi, Y.; Ahmad, A.; Khan, W. A.; Misiura, M.; Gallinaro, M.; Belyaev, A.; Hansen, M.; Schäfer, C.; Donegà, M.; Pauss, F.; Theofilatos, K.; Hinzmann, A.; Lu, Y. J.; Yu, S. S.; Dozen, C.; Hos, I.; Yücel, M.; Petyt, D.; Acosta, M. Vazquez; Khan, A.; Turner, M.; Heister, A.; Ferapontov, A.; Conway, J.; Everaerts, P.; Farrell, C.; Weber, M.; Palmer, C.; Pieri, M.; Welke, C.; Duarte, J.; Wilkinson, R.; Chu, J.; Salvati, E.; Whitmore, J.; Hewamanage, S.; Varelas, N.; Tan, P.; Gritsan, A. V.; Gray, J.; Noonan, D.; Cali, I. A.; Chan, M.; Lee, Y.-J.; Luckey, P. D.; Rusack, R.; Bose, S.; Baumgartel, D.; Mucia, N.; Lynch, S.; Pearson, T.; Winer, B. L.; Radburn-Smith, B. C.; Wang, F.; Garcia-Bellido, A.; Hidas, D.; Schnetzer, S.; Cox, B.; Karchin, P. E.; Dasu, S.
The journal of high energy physics, 09/2014, Letnik: 2014, Številka: 9Journal Article
A bstract Production of prompt J/ ψ meson pairs in proton-proton collisions at s = 7 TeV is measured with the CMS experiment at the LHC in a data sample corresponding to an integrated luminosity of about 4.7 fb −1 . The two J/ ψ mesons are fully reconstructed via their decays into μ + μ − pairs. This observation provides for the first time access to the high-transverse-momentum region of J/ ψ pair production where model predictions are not yet established. The total and differential cross sections are measured in a phase space defined by the individual J/ ψ transverse momentum ( p T J/ ψ ) and rapidity (| y J/ ψ |): | y J/ ψ | < 1.2 for p T J/ ψ > 6.5 GeV/ c ; 1.2 < | y J/ ψ | < 1.43 for a p T threshold that scales linearly with | y J/ ψ | from 6.5 to 4.5 GeV/ c ; and 1.43 < | y J/ ψ | < 2.2 for p T J/ ψ > 4.5 GeV/ c . The total cross section, assuming unpolarized prompt J/ ψ pair production is 1.49 ± 0.07 (stat) ±0.13 (syst) nb. Different assumptions about the J/ ψ polarization imply modifications to the cross section ranging from −31% to +27%.
