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arXiv · hep-ex/0306047

Measurement of Decay Parameters for $Ξ^{-} \to Λπ^{-}$ Decay

FNAL E756 Collaboration·A. Chakravorty·H. T. Diehl·J. Duryea·G. Guglielmo·K. Heller·P. M. Ho·C. James·K. Johns·D. M Kaplan·M. J. Longo·K. B. Luk·R. Rameika·H. A. Rubin·S. Teige·G. B. Thomson·Y. Zou
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Abstract

Based on 1.35 million polarized $Ξ^{-}$ events, we measure the parameter $ϕ_Ξ$ to be $-1.61^{\circ} \pm 2.66^{\circ} \pm 0.37^{\circ}$ for $Ξ^{-} \to Λπ^{-}$ decay. New results for the parameters $β_Ξ$ and $γ_Ξ$ are also presented. Assuming that the CP-violating phase-shift difference is negligible, we deduce the strong phase-shift difference between the P-wave and S-wave amplitudes of the $Λπ$ final state to be $3.17^{\circ} \pm 5.28^{\circ} \pm 0.73^{\circ}$. This strong phase-shift difference reduces the theoretical uncertainty in estimating the level of CP violation in $Ξ$-hyperon decay.

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FNAL E756 Collaboration, A. Chakravorty, H. T. Diehl, J. Duryea, G. Guglielmo, K. Heller, P. M. Ho, C. James, K. Johns, D. M Kaplan, M. J. Longo, K. B. Luk, R. Rameika, H. A. Rubin, S. Teige, G. B. Thomson, Y. Zou. 2003-06-24. Measurement of Decay Parameters for $Ξ^{-} \to Λπ^{-}$ Decay. https://doi.org/10.1103/physrevlett.91.031601

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