New Measurement of the <span class="aps-inline-formula"><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>π</mi><mo>→</mo><mi>e</mi><mi>ν</mi></math></span> Branching Ratio

D. A. Bryman; R. Dubois; T. Numao; B. Olaniyi; A. Olin; M. S. Dixit; D. Berghofer; J. -M. Poutissou; J. A. Macdonald; B. C. Robertson

doi:10.1103/PhysRevLett.50.7

New Measurement of the $π \to e ν$ Branching Ratio

D. A. Bryman, R. Dubois, T. Numao, B. Olaniyi, A. Olin, M. S. Dixit, D. Berghofer, J. -M. Poutissou, J. A. Macdonald, and B. C. Robertson

Phys. Rev. Lett. 50, 7 – Published 3 January 1983

Abstract

A new measurement of the $π \to e ν$ branching ratio yields $\frac{Γ (π \to e ν + π \to e ν γ)}{Γ (π \to μ ν + π \to μ ν γ)} = (1.218 \pm 0.014) \times 10^{- 4}$ . The measured value is in good agreement with the standard-model prediction incorporating electron-muon universality.