Search for CP and $P$ violating pseudoscalar decays into $\pi \pi$

The BESIII Collaboration, M. Ablikim

Using a sample of $(225.2\pm 2.8)\times 10^6$ $J/\psi$ events collected with the Beijing Spectrometer (BESIII) at the Beijing Electron-Positron Collider, CP and $P$ violating decays o…