Abstract : Pair production of Upsilon(1S) mesons is observed at the LHC in proton-proton collisions at sqrt(s) = 8 TeV by the CMS experiment in a data sample corresponding to an integrated luminosity of 20.7 inverse-femtobarns. Both Upsilon(1S) candidates are fully reconstructed via their decays to mu+ mu-. The fiducial acceptance region is defined by an absolute Upsilon(1S) rapidity smaller than 2.0. The fiducial cross section for the production of Upsilon(1S) pairs, assuming that both mesons decay isotropically, is measured to be 68.8 +/- 12.7 (stat) +/- 7.4 (syst) +/- 2.8 (B) pb, where the third uncertainty comes from the uncertainty in the branching fraction of Upsilon(1S) decays to mu+ mu-. Assuming instead that the Upsilon(1S) mesons are produced with different polarizations leads to variations in the measured cross section in the range from -38% to +36%.
Type de document :
Article dans une revue
Journal of High Energy Physics, Springer Verlag (Germany), 2017, 05, pp.013. 〈10.1007/JHEP05(2017)013〉
http://hal.in2p3.fr/in2p3-01387006
Contributeur : Sylvie Flores
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Soumis le : mardi 25 octobre 2016 - 07:17:56
Dernière modification le : jeudi 12 avril 2018 - 01:50:17
V. Khachatryan, M. Besançon, F. Couderc, M. Dejardin, D. Denegri, et al.. Observation of Upsilon(1S) pair production in proton-proton collisions at sqrt(s) = 8 TeV. Journal of High Energy Physics, Springer Verlag (Germany), 2017, 05, pp.013. 〈10.1007/JHEP05(2017)013〉. 〈in2p3-01387006〉
