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arXiv · hep-ex/9905060

Observation of Direct CP Violation in K_{S,L} to ππDecays

KTeV Collaboration
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Abstract

We have compared the decay rates of K_L and K_S to π^+ π^- and π^0 π^0 final states using a subset of the data from the KTeV experiment (E832) at Fermilab. We find that the direct-CP-violation parameter Re(ε'/ε) is equal to (28.0 \pm 3.0 (stat) \pm 2.8 (syst)) \times 10^{-4}. This result definitively establishes the existence of CP violation in a decay process.

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KTeV Collaboration. 1999-06-08. Observation of Direct CP Violation in K_{S,L} to ππDecays. https://doi.org/10.1103/physrevlett.83.22

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