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arXiv · 1809.01153

Precise determination of the branching ratio of the neutral-pion Dalitz decay

Tomáš Husek·Evgueni Goudzovski·Karol Kampf
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Abstract

We provide a new value for the ratio $R={Γ(π^0\to e^+e^-γ(γ))}/{Γ(π^0\toγγ)}=11.978(6)\times10^{-3}$, which is by two orders of magnitude more precise than the current Particle Data Group average. It is obtained using the complete set of the next-to-leading-order radiative corrections in the QED sector, and incorporates up-to-date values of the $π^0$-transition-form-factor slope. The ratio $R$ translates into the branching ratios of the two main $π^0$ decay modes: $\mathcal{B}(π^0\toγγ)=98.8131(6)\,\%$ and $\mathcal{B}(π^0\to e^+e^-γ(γ))=1.1836(6)\,\%$.

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Tomáš Husek, Evgueni Goudzovski, Karol Kampf. 2019-01-07. Precise determination of the branching ratio of the neutral-pion Dalitz decay. https://doi.org/10.1103/physrevlett.122.022003

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