Observation of Upsilon(1S) pair production in proton-proton collisions at sqrt(s) = 8 TeV

V. Khachatryan , M. Besançon (1) , F. Couderc (1) , M. Dejardin (1) , D. Denegri (1) , B. Fabbro (1) , J.L. Faure (1) , C. Favaro (1) , F. Ferri (1) , S. Ganjour (1) , S. Ghosh (1) , A. Givernaud (1) , P. Gras (1) , G. Hamel De Monchenault (1) , P. Jarry (1) , I. Kucher (1) , E. Locci (1) , M. Machet (1) , J. Malcles (1) , J. Rander (1) , A. Rosowsky (1) , M. Titov (1) , A. Zghiche (1) , A. Abdulsalam (2) , I. Antropov (2) , S. Baffioni (2) , F. Beaudette (2) , P. Busson (2) , L. Cadamuro (2) , E. Chapon (2) , C. Charlot (2) , O. Davignon (2) , R. Granier De Cassagnac (2) , M. Jo (2) , S. Lisniak (2) , P. Mine (2) , C. Ochando (2) , M. Nguyen (2) , G. Ortona (2) , P. Paganini (2) , P. Pigard (2) , S. Regnard (2) , R. Salerno (2) , Y. Sirois (2) , T. Strebler (2) , Y. Yilmaz (2) , A. Zabi (2) , J.-L. Agram (3) , J. Andrea (3) , A. Aubin (3) , D. Bloch (3) , J.-M. Brom (3) , M. Buttignol (3) , E.C. Chabert (3) , N. Chanon (3) , C. Collard (3) , E. Conte (3) , X. Coubez (3) , J.-C. Fontaine (3) , D. Gele (3) , U. Goerlach (3) , A.-C. Le Bihan (3) , K. Skovpen (3) , P. Van Hove (3) , S. Gadrat (4) , S. Beauceron (5) , C. Bernet (5) , G. Boudoul (5) , E. Bouvier (5) , C.A. Carrillo Montoya (5) , R. Chierici (5) , D. Contardo (5) , B. Courbon (5) , P. Depasse (5) , H. El Mamouni (5) , J. Fan (5) , J. Fay (5) , S. Gascon (5) , M. Gouzevitch (5) , G. Grenier (5) , B. Ille (5) , Fabienne Lagarde (5) , I.B. Laktineh (5) , M. Lethuillier (5) , L. Mirabito (5) , A.L. Pequegnot (5) , S. Perries (5) , A. Popov (5) , D. Sabes (5) , V. Sordini (5) , M. Vander Donckt (5) , P. Verdier (5) , S. Viret (5)

1 IRFU - Institut de Recherches sur les lois Fondamentales de l'Univers
2 LLR - Laboratoire Leprince-Ringuet
3 DRS-IPHC - Département Recherches Subatomiques
4 CC-IN2P3 - Centre de Calcul de l'IN2P3
5 IPNL - Institut de Physique Nucléaire de Lyon

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%.

Domaines: Physique des Hautes Energies - Expérience [hep-ex]

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, 2017, 05, pp.013. ⟨10.1007/JHEP05(2017)013⟩. ⟨in2p3-01387006⟩