The Fermilab E799 Collaboration has carried out a search for the rare decay 0e+e- using 0s produced from KL'000 decays in flight. We observe a signal of nine events with an e+e- mass close to the 0 mass where only one event is predicted from other known processes. From this, we measure B(0e+e-,(mee/m0)20. 95) =[7.6-2.8+3.9(stat)0.5(syst)]×10-8, over and above the contribution from 0 Dalitz decays. Correcting for radiative effects, we find this result consistent with theoretical expectations from standard-model processes.
ASJC Scopus subject areas
- Physics and Astronomy(all)