The rare decay KL0→π0π0νν̄ was studied with the E391a detector at the KEK 12-GeV proton synchrotron. Based on 9.4×109 KL0 decays, an upper limit of 8.1×10-7 was obtained for the branching fraction at 90% confidence level. We also set a limit on the KL0→π0π0X (X→invisible particles) process; the limit on the branching fraction varied from 7.0×10-7 to 4.0×10 -5 for the mass of X ranging from 50MeV/c2 to 200MeV/c2.
|Journal||Physical Review D - Particles, Fields, Gravitation and Cosmology|
|Publication status||Published - Sep 21 2011|
ASJC Scopus subject areas
- Nuclear and High Energy Physics
- Physics and Astronomy (miscellaneous)