Search for CP and P violating pseudoscalar decays into ππ

Abstract

Using a sample of (225.2±2.8)×106 J/ψ events collected with the Beijing Spectrometer at the Beijing Electron-Positron Collider, CP and P violating decays of η, η ′, and η c into π +π - and π0π0 are searched for in J/ψ radiative decays. No significant η, η ′, or η c signal is observed, and 90% confidence level upper limits of B(η→π +π -)<3.9×10 -4, B(η ′→π +π -)<5. 5×10 -5, B(η c→π +π -)<1.3×10 -4, B(η→π0π0)<6. 9×10 -4, B(η ′→π0π0)<4. 5×10 -4, and B(η c→π0π0)<4. 2×10 -5 are obtained. © 2011 American Physical Society.