Measurement of the Λb polarization and angular parameters in Λb →j /ψ Λ decays from pp collisions at s =7 and 8 TeV MEASUREMENT of the Λb POLARIZATION ⋯ A. M. SIRUNYAN et al.

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Date
2018-04-01
Authors
Sirunyan, A. M.
Tumasyan, A.
Adam, W.
Ambrogi, F.
Asilar, E.
Bergauer, T.
Brandstetter, J.
Brondolin, E.
Dragicevic, M.
Erö, J.
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Abstract
An analysis of the bottom baryon decay Λb→J/ψ(→μ+μ-)Λ(→pπ-) is performed to measure the Λb polarization and three angular parameters in data from pp collisions at s=7 and 8 TeV, collected by the CMS experiment at the Large Hadron Collider. The Λb polarization is measured to be 0.00±0.06(stat)±0.06(syst) and the parity-violating asymmetry parameter is determined to be 0.14±0.14(stat)±0.10(syst). The measurements are compared to various theoretical predictions, including those from perturbative quantum chromodynamics.
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Physical Review D. v.97(7)