Observation of cp violation in KL → π+πe+e decays

KTeV Collaboration

Research output: Contribution to journalArticlepeer-review

85 Scopus citations


We report the first observation of a manifestly CP violating effect in the KL → π+πe+e decay mode. A large asymmetry was observed in the distribution of these decays in the CP-odd and T-odd angle φ between the decay planes of the e+e and π+π pairs in the KL 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 when integrating over the entire phase space of a mode and the first such effect observed in an angular variable.

Original languageEnglish (US)
Pages (from-to)408-411
Number of pages4
JournalPhysical review letters
Issue number3
StatePublished - 2000

ASJC Scopus subject areas

  • General Physics and Astronomy


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