English

Improved Standard-Model prediction for $\pi^0\to e^+e^-$

High Energy Physics - Phenomenology 2022-05-02 v2 High Energy Physics - Experiment High Energy Physics - Lattice Nuclear Theory

Abstract

We present an improved Standard-Model (SM) prediction for the dilepton decay of the neutral pion. The loop amplitude is determined by the pion transition form factor for π0γγ\pi^0\to\gamma^*\gamma^*, for which we employ a dispersive representation that incorporates both space-like and time-like data as well as short-distance constraints. The resulting SM branching fraction, BR[π0e+e]=6.25(3)×108\text{BR}[\pi^0\to e^+e^-]=6.25(3)\times 10^{-8} , sharpens constraints on physics beyond the SM, including pseudoscalar and axial-vector mediators.

Keywords

Cite

@article{arxiv.2105.04563,
  title  = {Improved Standard-Model prediction for $\pi^0\to e^+e^-$},
  author = {Martin Hoferichter and Bai-Long Hoid and Bastian Kubis and Jan Lüdtke},
  journal= {arXiv preprint arXiv:2105.04563},
  year   = {2022}
}

Comments

9 pages, 3 figures; journal version

R2 v1 2026-06-24T01:57:33.943Z