The branching ratio of the rare decay π0→e+e- has been measured precisely, using the complete data set from the KTeV E799-II experiment at Fermilab. We observe 794 candidate π0→e+e- events using KL→3π0 as a source of tagged π0s. The expected background is 52.7±11.2 events, predominantly from high e+e- mass π0→e+e-γ decays. We have measured B(π0→e+e-,(me+e-/mπ0)2>0.95)=(6.44±0. 25stat±0.22syst)×10-8, which is above the unitary bound from π0→γγ and within the range of theoretical expectations from the standard model.
|Original language||English (US)|
|Journal||Physical Review D - Particles, Fields, Gravitation and Cosmology|
|State||Published - 2007|
ASJC Scopus subject areas
- Nuclear and High Energy Physics
- Physics and Astronomy (miscellaneous)