6533b7dafe1ef96bd126eaea

RESEARCH PRODUCT

Radiative corrections for Dalitz decays of π0, η(′) and Σ0

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Abstract We briefly summarize current experimental and theoretical results on the π 0 Dalitz decay, and provide a new value for the ratio R = Γ ( π 0 → e + e − γ ( γ ) ) / Γ ( π 0 → γ γ ) = 11.978 ( 6 ) × 10 − 3 , which is by two orders of magnitude more precise than the current PDG average. This value 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. Furthermore, we present the complete set of radiative corrections for the Dalitz decays η ( ′ ) → l + l − γ beyond the soft-photon approximation. The corrections inevitably depend on the η ( ′ ) → γ ⁎ γ ( ⁎ ) transition form factors. Finally, we discuss radiative corrections for the Σ 0 → Λ e + e − decay.