2023-05-302023-05-302019ABOUZAID, E. et al. Measurement of the branching ratio of Dalitz decay using decays. Physical Review D, Washington, v. 100, n. 3, e032003, 2019. DOI: 10.1103/PhysRevD.100.032003. Disponível em: https://journals.aps.org/prd/abstract/10.1103/PhysRevD.100.032003. Acesso em: 16 maio 2023.e- 2470-00292470-0010http://repositorio.bc.ufg.br/handle/ri/22638We present a measurement of Bðπ0 → eþe−γÞ=Bðπ0 → γγÞ, the Dalitz branching ratio, using data taken in 1999 by the E832 KTeV experiment at Fermi National Accelerator Laboratory. We use neutral pions from fully reconstructed KL decays in flight; the measurement is based on ∼60 thousand KL → π0π0π0 → γγγγeþe−γ decays. We normalize to KL → π0π0π0 → 6γ decays. We find Bðπ0 → eþe−γÞ=Bðπ0 → γγÞ ðmeþe− > 15 MeV=c2Þ¼½3.920 0.016ðstatÞ 0.036ðsystÞ × 10−3. Using the Mikaelian and Smith prediction for the eþe− mass spectrum, we correct the result to the full eþe− mass range. The corrected result is Bðπ0 → eþe−γÞ=Bðπ0 → γγÞ¼½1.1559 0.0047ðstatÞ 0.0106ðsystÞ %. This result is consistent with previous measurements, and the uncertainty is a factor of 3 smaller than any previous measurement.engAcesso AbertoArtigo10.1103/PhysRevD.100.032003