Measurement of prompt J/ψ and beauty hadron production cross sections at mid-rapidity in pp collisions at $ \sqrt{s}=7 $ TeV

Betty Abelev, Jaroslav Adam, Dagmar Adamova, Andrew Marshall Adare, Madan Aggarwal, Gianluca Aglieri Rinella, Andras Gabor Agocs, Andrea Agostinelli, Saul Aguilar Salazar, Zubayer Ahammed, Arshad Ahmad, Nazeer Ahmad (+981 others)
2012 Journal of High Energy Physics  
The ALICE experiment at the LHC has studied J/psi production at mid-rapidity in pp collisions at sqrts=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 p_t>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
more » ... uch as the Psi(2S) and Csi_c resonances, is sigma_prompt-J/psi(pt > 1.3 GeV/c, |y| < 0.9) = 8.3 +- 0.8(stat.) +- 1.1(syst.) + 1.5 - 1.4(syst. pol.) micro barn. The cross section for the production of b-hadrons decaying to J/psi with p_t>1.3 GeV/c and |y|<0.9 is sigma_J/psi<-h_B = 1.46 +- 0.38(stat.) + 0.26 -0.32(syst.) micro barn. The results are compared to QCD model predictions. The shape of the p_t and y distributions of b-quarks predicted by perturbative QCD model calculations are used to extrapolate the measured cross section to derive the b-bbar pair total cross section and dsigma/dy at mid-rapidity.
doi:10.1007/jhep11(2012)065 fatcat:6izxv2xevnektcusqldvol4xzu