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arXiv · hep-ex/9908020

Observation of CP Violation in K(L)->pi+pi-e+e- Decays

KTeV Collaboration
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Abstract

We report the first observation of a manifestly CP violating effect in the K(L)->pi+pi-e+e- decay mode. A large asymmetry was observed in the distribution of these decays in the CP-odd and T-odd angle phi between the decay planes of the e+e- and pi+pi- pairs in the K(L) center of mass system. After acceptance corrections, the overall asymmetry is found to be 13.6+-2.5 (stat) +-1.2 (syst)%. This is the largest CP-violating effect yet observed integrating over the entire phase space of a mode and the first such effect observed in an angular variable.

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KTeV Collaboration. 1999-08-05. Observation of CP Violation in K(L)->pi+pi-e+e- Decays. https://doi.org/10.1103/physrevlett.84.408

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