Measurement of prompt J/psi pair production in pp collisions at sqrt(s) = 7 TeV

V. Khachatryan , S. Baffioni (1) , F. Beaudette (1) , P. Busson (1) , C. Charlot (1) , T. Dahms (1) , M. Dalchenko (1) , L. Dobrzynski (1) , N. Filipovic (1) , A. Florent (1) , R. Granier de Cassagnac (1) , L. Mastrolorenzo (1) , P. Mine (1) , C. Mironov (1) , I.N. Naranjo (1) , M. Nguyen (1) , C. Ochando (1) , P. Paganini (1) , R. Salerno (1) , J.B. Sauvan (1) , Y. Sirois (1) , C. Veelken (1) , Y. Yilmaz (1) , A. Zabi (1) , J.-L. Agram (2) , J. Andrea (2) , A. Aubin (2) , D. Bloch (2) , J.-M. Brom (2) , E.C. Chabert (2) , C. Collard (2) , E. Conte (2) , J.-C. Fontaine (2) , D. Gele (2) , U. Goerlach (2) , C. Goetzmann (2) , A.-C. Le Bihan (2) , P. van Hove (2) , S. Gadrat (3) , S. Beauceron (4) , N. Beaupere (4) , G. Boudoul (4) , S. Brochet (4) , C.A. Carrillo Montoya (4) , J. Chasserat (4) , R. Chierici (4) , D. Contardo (4) , P. Depasse (4) , H. El Mamouni (4) , J. Fan (4) , J. Fay (4) , S. Gascon (4) , M. Gouzevitch (4) , B. Ille (4) , T. Kurca (4) , M. Lethuillier (4) , L. Mirabito (4) , S. Perries (4) , J.D. Ruiz Alvarez (4) , D. Sabes (1, 4) , L. Sgandurra (4) , V. Sordini (4) , M. Vander Donckt (4) , P. Verdier (4) , S. Viret (4) , H. Xiao (4)

1 LLR - Laboratoire Leprince-Ringuet
2 IPHC - Institut Pluridisciplinaire Hubert Curien
3 CC-IN2P3 - Centre de Calcul de l'IN2P3
4 IPNL - Institut de Physique Nucléaire de Lyon

Production of prompt J/psi meson pairs in proton-proton collisions at sqrt(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 inverse femtobarns. The two J/psi mesons are fully reconstructed via their decays into muon pairs. This observation provides for the first time access to the high-transverse-momentum region of J/psi 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/psi transverse momentum pt[J/psi] and rapidity abs(y[J/psi]): abs(y[J/psi]) < 1.2 for pt[J/psi] > 6.5 GeV; 1.2 < abs(y[J/psi]) < 1.43 for a pt threshold that scales linearly with abs(y[J/psi]) from 6.5 to 4.5 GeV; and 1.43 < abs(y[J/psi]) < 2.2 for pt[J/psi] > 4.5 GeV. The total cross section, assuming unpolarized prompt J/psi pair production is 1.49 +/- 0.07 (stat.) +/- 0.13 (syst.) nb. Different assumptions about the J/psi polarization imply modifications to the cross section ranging from -31% to +27%.

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

V. Khachatryan, S. Baffioni, F. Beaudette, P. Busson, C. Charlot, et al.. Measurement of prompt J/psi pair production in pp collisions at sqrt(s) = 7 TeV. Journal of High Energy Physics, 2014, 09(2014), pp.094. ⟨10.1007/JHEP09(2014)094⟩. ⟨in2p3-00998920⟩