Measurement of the branching ratio of pi0 ---> e+ e- using K(L) ---> 3 pi0 decays in flight
Journal
Physical Review Letters
Journal Volume
83
Pages
922-925
Date Issued
1999-03
Author(s)
Alavi-Harati, A. et al.
Abstract
The branching ratio of the rare decay π0 → e+e- has been measured in E799-II, a rare kaon decay experiment using the KTeV detector at Fermilab. We observed 275 candidate π0 → e+e- events, with an expected background of 21.4 ± 6.2 events which includes the contribution from Dalitz decays. We measured B[π0 → e+e-,(me+e-/mπ0)2 > 0.95] = (6.09 ± 0.40 ± 0.24) × 10-8, where the first error is statistical and the second systematic. This result is the first significant observation of the excess rate for this decay above the unitarity lower bound. © 1999 The American Physical Society.
Type
journal article