Date of this Version
Physics Letters B 714 (2012) 136–157; http://dx.doi.org/10.1016/j.physletb.2012.05.063
The Λb differential production cross section and the cross section ratio σ(Λ̅b )/σ(Λb) are measured as functions of transverse momentum pΛbT and rapidity |yΛb | in pp collisions at √ s = 7 TeV using data collected by the CMS experiment at the LHC. The measurements are based on Λb decays reconstructed in the exclusive final state J/ψΛ, with the subsequent decays J/ψ →μ+μ− and Λ→pπ, using a data sample corresponding to an integrated luminosity of 1.9 fb−1. The product σ(Λb) × B(Λb →J/ψΛ) versus pΛbT falls faster than that of b mesons. The measured value of σ(Λb) × B(Λb →J/ψΛ) for pΛbT > 10 GeV and |yΛb | < 2.0 is 1.16±0.06±0.12 nb, and the integrated σ(Λ̅b)/σ(Λb) ratio is 1.02±0.07±0.09, where the uncertainties are statistical and systematic, respectively.