Observation of the Λ[0 over b] → J/ψ pπ[superscript −] decay
Author(s)Counts, Ian Thomas Hunt; Ilten, Philip James; Williams, Michael
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The first observation of the Cabibbo-suppressed decay Λ [0 over b] → J/ψpπ [superscript −] is reported using a data sample of proton-proton collisions at 7 and 8 TeV, corresponding to an integrated luminosity of 3 fb[superscript −1]. A prominent signal is observed and the branching fraction relative to the decay mode Λ [0 over b] → J/ψpK [superscript −] is determined to be B(Λ[0 over b] → J/ψpπ[superscript −])/B(Λ[0 over b] → J/ψpK[superscript −]) = 0.0824 ± 0.0025 (stat) ± 0.0042 (syst). A search for direct CP violation is performed. The difference in the CP asymmetries between these two decays is found to be A[subscript CP](Λ[0 over b] → J/ψpπ[superscript −]) − A[subscript CP](Λ[0 over b] → J/ψpK[superscript −]) = (+5.7 ± 2.4 (stat) ± 1.2 (syst))%, which is compatible with CP symmetry at the 2.2σ level.
DepartmentMassachusetts Institute of Technology. Department of Physics; Massachusetts Institute of Technology. Laboratory for Nuclear Science
Journal of High Energy Physics
Aaij, R., B. Adeva, M. Adinolfi, A. Affolder, Z. Ajaltouni, S. Akar, J. Albrecht, et al. “Observation of the Λ[0 over b] → J/ψ pπ[superscript −] decay.” J. High Energ. Phys. 2014, no. 7 (July 2014). © CERN, for the benefit of the LHCb Collaboration
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