Measurement of the cp-violation parameter η+-γ in neutral kaon decays

E. J. Ramberg, G. J. Bock, R. Coleman, J. Enagonio, Y. B. Hsiung, K. Stanfield, R. Tschirhart, T. Yamanaka, E. C. Swallow, G. Blair, G. D. Gollin, M. Karlsson, J. K. Okamitsu, P. Debu, B. Peyaud, R. Turlay, B. Vallage

Research output: Contribution to journalArticlepeer-review


Interference between KS and KL decays into the final state π+π-γ has been observed in experiment 731 at Fermilab. By fitting the distribution of decays downstream of a regenerator, a new CP-violation parameterη+-γ, analogous to η+-, has been measured, with its magnitude equal to(2.15±0.26±0.20)×10-3, and φ+-γ, the associated phase angle, equal to(72±23±17)°. Assuming that any difference between this fit value for η+-γ and the previously measured value forη+- can be attributed to direct CP violation in this decay, a limit of|ε+-γ′|/ε<0.3 at the 90% confidence level has been made.

Original languageEnglish (US)
Pages (from-to)2529-2532
Number of pages4
JournalPhysical review letters
Issue number17
StatePublished - 1993
Externally publishedYes

ASJC Scopus subject areas

  • Physics and Astronomy(all)


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