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Search for CP Violation in the decays D+ -> K_S pi+ and D+ -> K_S K+

The FOCUS Collaboration
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Abstract

A high statistics sample of photo-produced charm from the FOCUS(E831) experiment at Fermilab has been used to search for direct CP violation in the decays D+->K_S pi+ and D+ -> K_S K+. We have measured the following asymmetry parameters relative to D+->K-pi+pi+: A_CP(K_S pi+) = (-1.6 +/- 1.5 +/- 0.9)%, A_CP(K_S K+) = (+6.9 +/- 6.0 +/- 1.5)% and A_CP(K_S K+) = (+7.1 +/- 6.1 +/- 1.2)% relative to D+->K_S pi+. The first errors quoted are statistical and the second are systematic. We also measure the relative branching ratios: Γ(D+->\bar{K0}pi+)/Γ(D+->K-pi+pi+) = (30.60 +/- 0.46 +/- 0.32)%, Γ(D+->\bar{K0}K+)/Γ(D+->K-pi+pi+) = (6.04 +/- 0.35 +/- 0.30)% and Γ(D+->\bar{K0}K+)/Γ(D+->\bar{K0}pi+) = (19.96 +/- 1.19 +/- 0.96)%.

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The FOCUS Collaboration. 2001-09-17. Search for CP Violation in the decays D+ -> K_S pi+ and D+ -> K_S K+. https://doi.org/10.1103/physrevlett.88.041602

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