Measurement of the parity-violating asymmetry parameter α[subscript b] and the helicity amplitudes for the decay Λ[0 over b] → J/ψΛ[superscript 0] with the ATLAS detector
Author(s)Taylor, Frank E.
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A measurement of the parity-violating decay asymmetry parameter, α[subscript b], and the helicity amplitudes for the decay Λ[0 over b] → J/ψ(μ[superscript +]μ[superscript −])Λ[superscript 0](pπ[superscript −]) is reported. The analysis is based on 1400 Λ[0 over b] and [bar over Λ][0 over b] baryons selected in 4.6 fb[superscript −1] of proton–proton collision data with a center-of-mass energy of 7 TeV recorded by the ATLAS experiment at the LHC. By combining the Λ[0 over b] and [bar over Λ][0 over b] samples under the assumption of CP conservation, the value of α[subscript b] is measured to be 0.30 ± 0.16(stat) ± 0.06(syst). This measurement provides a test of theoretical models based on perturbative QCD or heavy-quark effective theory.
DepartmentMassachusetts Institute of Technology. Department of Physics
Physical Review D
American Physical Society
Aad, G., T. Abajyan, B. Abbott, J. Abdallah, S. Abdel Khalek, O. Abdinov, R. Aben, et al. “Measurement of the Parity-Violating Asymmetry Parameter α[subscript b] and the Helicity Amplitudes for the Decay Λ[0 over b] → J/ψΛ[superscript 0] with the ATLAS Detector.” Phys. Rev. D 89, no. 9 (May 2014). © 2014 CERN, for the ATLAS Collaboration
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