Measurement of the ${\mathrm{\pi }}^{+}$→${\mathit{e}}^{+}$ν branching ratio

A new measurement of the ${\mathrm{\pi }}^{+}$→${\mathit{e}}^{+}$ν branching ratio gives ${\mathit{R}}_{\mathrm{\pi }\mathit{e}\nu }$=Γ(π→eν+π→eνγ)/Γ (π→μν+π→μνγ) =[1.2265±0.0034(stat)±0.0044(sys)]×${10}^{\mathrm{-}4}$. This result is in agreement with standard model calculations and confirms the hypothesis of electron-muon universality at the 0.2% level.