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Journal of High Energy Physics 2012 (2012) 065
Measurement of prompt and non-prompt J/psi production cross sections at mid-rapidity in pp collisions at sqrt(s) = 7 TeV
B. Abelev, L. Aphecetche1, A. Baldisseri2, Guillaume Batigne1, I. Belikov3, A.A.E. Bergognon1, H. Borel2, M. Bregant1, J. Castillo Castellanos2, J.L. Charvet2, c. Cheshkov4, B. Cheynis4, H. Delagrange1, O. Driga1, L. Ducroux4, M. Estienne1, M. Germain1, J.-Y. Grossiord4, M. Guilbaud4, B. Hippolyte3, S. Jangal3, C. Kuhn3, A. Lardeux1, F. Lef'evre1, M. Lenhardt1, L. Luquin1, G. Martınez Garcıa1, A. Mas1, L. Massacrier1, 4, A. Matyja1, S. Pal2, H. Pereira Da Costa2, P. Pillot1, A. Rakotozafindrabe2, C. Roy3, X. Sanchez Castro3, Y. Schutz1, A. Shabetai1, D. Stocco1, R. Tieulent4, A. Uras4, R. Vernet5, R. Wan3, H. Yang2, Y. Zoccarato4, N. Arbor6, G. Conesa Balbastre6, J. Faivre6, C. Furget6, R. Guernane6, S. Kox6, J.S. Real6, C. Silvestre6, Sang Un Ahn7, Y. .W. Baek7, A. Baldit7, V. Barret7, N. Bastid7, P. Crochet7, P. Dupieux7, R. Ichou7, X. Lopez7, F. Manso7, M. Marchisone7, S. Porteboeuf-Houssais7, P. Rosnet7, B. Vulpescu7, X. Zhang7
ALICE Collaboration(s)

The ALICE experiment at the LHC has studied J/psi production at mid-rapidity in pp collisions at {\surd}s = 7 TeV through its electron pair decay on a data sample corresponding to an integrated luminosity L_int = 5.6nb-1. The fraction of J/psi from the decay of long-lived beauty hadrons was determined for J/psi candidates with transverse momentum pt > 1.3 GeV/c and rapidity |y| < 0.9. The cross section for prompt J/psi mesons, i.e. directly produced J/psi and prompt decays of heavier charmonium states such as the Psi(2S) and Csi_c resonances, is sigma_prompt-J/psi(pt > 1.3 GeV/c, |y| < 0.9) = 7.2 +- 0.7(stat.) +- 1.0(syst.)+1.3-1.2 (syst.pol.) mb. The pt-differential cross section for prompt J/psi has also been measured. The cross section for the production of b-hadrons decaying to J/psi with transverse momentum greater than 1.3 GeV/c in the rapidity range |y| < 0.9 is sigma_{J/psi<-h_B} = 1.26 +- 0.33 (stat.) +0.23-0.28 (syst.) mb. The results are compared to QCD model predictions. The shape of the pt and y distributions of b-quarks predicted by perturbative QCD model calculations are used to extrapolate the measured cross section to derive the bb pair total cross section and dsigma/dy at midrapidity.
1 :  SUBATECH - Laboratoire SUBATECH Nantes
2 :  IRFU - Institut de Recherches sur les lois Fondamentales de l'Univers (ex DAPNIA)
3 :  DRS-IPHC - Département Recherches Subatomiques
4 :  IPNL - Institut de Physique Nucléaire de Lyon
5 :  CC IN2P3 - Centre de Calcul de l'inst. national de phy. nucléaire et de phy. des particules
6 :  LPSC - Laboratoire de Physique Subatomique et de Cosmologie
7 :  LPC - Laboratoire de Physique Corpusculaire [Clermont-Ferrand]
Laboratoire de Physique Corpusculaire
Physique/Physique des Hautes Energies - Expérience
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