Measurement of the Λb cross section and the Λb to Λb ratio with J/ψΛ decays in pp collisions at √s = 7 TeV

Authors

• CMS Collaboration
• Ekaterina Avdeeva, University of Nebraska-LincolnFollow
• Kenneth A. Bloom, University of Nebraska-LincolnFollow
• S. Bose, University of Nebraska-LincolnFollow
• Jamila Butt, University of Nebraska-Lincoln
• Daniel R. Claes, University of Nebraska-LincolnFollow
• Aaron Dominguez, University of Nebraska-LincolnFollow
• Michael Eads, University of Nebraska-LincolnFollow
• P. Jindal, University of Nebraska-Lincoln
• J. Keller, University of Nebraska-LincolnFollow
• Ilya Kravchenko, University of Nebraska-LincolnFollow
• J. Lazo-Flores, University of Nebraska-LincolnFollow
• Helena Malbouisson, University of Nebraska-Lincoln
• Sudhir Malik, University of Nebraska-LincolnFollow
• Gregory Snow, University of Nebraska-LincolnFollow

Document Type

Article

Date of this Version

2012

Citation

Physics Letters B 714 (2012) 136–157; http://dx.doi.org/10.1016/j.physletb.2012.05.063

Abstract

The Λ_b differential production cross section and the cross section ratio σ(Λ̅_b )/σ(Λ_b) are measured as functions of transverse momentum p^Λb_T and rapidity |y^Λb | in pp collisions at √ s = 7 TeV using data collected by the CMS experiment at the LHC. The measurements are based on Λ_b 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(Λ_b) × B(Λ_b →J/ψΛ) versus p^Λb_T falls faster than that of b mesons. The measured value of σ(Λ_b) × B(Λ_b →J/ψΛ) for p^Λb_T > 10 GeV and |y^Λb | < 2.0 is 1.16±0.06±0.12 nb, and the integrated σ(Λ̅_b)/σ(Λ_b) ratio is 1.02±0.07±0.09, where the uncertainties are statistical and systematic, respectively.