QED radiative corrections to the decay pi^0 to e^+e^-

TL;DR

This paper reevaluates QED radiative corrections to the decay of neutral pions into electron-positron pairs, highlighting two types of corrections with different origins and quantifying their overall impact.

Contribution

It provides a detailed analysis of QED radiative corrections, including their origins and effects on decay widths, improving precision in theoretical predictions.

Findings

Total radiative correction for pi^0 decay is approximately 3.2%.

Total radiative correction for eta decay is approximately 4.3%.

Identifies two distinct types of radiative corrections with different physical origins.

Abstract

We reconsider QED radiative corrections (RC) to the $\pi^{0}\to e^{+}e^{-}$ decay width. One kind of RC investigated earlier has a renormalization group origin and can be associated with the final state interaction of electron and positron. It determines the distribution of lepton pair invariant masses in the whole kinematic region. The other type of RC has a double-logarithmic character and is related to almost on-mass-shell behavior of the lepton form factors. The total effect of RC for the $\pi^{0}\to e^{+}e^{-}$ decay is estimated to be 3.2% and for the decay $\eta \to e^{+}e^{-}$ is 4.3%.