English

Parapositronium decay into three photons and implications for the neutral pion

High Energy Physics - Phenomenology 2026-02-17 v1

Abstract

We complete the determination of the parapositronium decay into three photons by evaluating amplitudes mediated by the ZZ boson. We show that, contrary to the expectation that the extra mass scale mem_e may bring an enhancement to the overall scaling, the amplitude turns out to start at 1/mZ61/m_Z^6 order, similarly to the WW boson mediated amplitude. The decay rate with both WW and ZZ boson contributions is found to be 1.110801.1\cdot 10^{-80} eV, about 47 orders of magnitude smaller than previously estimated. We also discuss its implication for the π03γ\pi^0\to3\gamma amplitude.

Keywords

Cite

@article{arxiv.2602.14899,
  title  = {Parapositronium decay into three photons and implications for the neutral pion},
  author = {Andrzej Czarnecki and Divyesh Dagia and Ting Gao and Ripanjeet Toor},
  journal= {arXiv preprint arXiv:2602.14899},
  year   = {2026}
}