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Standard Model estimate of $K^{+} \to π^{+} 4 e$ branching ratio

Department of Astronomy and Theoretical Physics, Lund University, Sölvegatan 14A, SE 223-62 Lund, Sweden

^*tomas.husek@thep.lu.se

Phys. Rev. D 106, L071301 – Published 10 October, 2022

DOI: https://doi.org/10.1103/PhysRevD.106.L071301

Abstract

The branching ratio of the $K^{+} \to π^{+} e^{+} e^{-} e^{+} e^{-}$ ( $K^{+} \to π^{+} 4 e$ ) decay is calculated at leading order in the Standard Model. The dominance of the neutral-pion pole determines the overall branching ratio to be $B (K^{+} \to π^{+} 4 e) = B (K^{+} \to π^{+} π^{0}) B (π^{0} \to 4 e) \approx 7.0 (3) \times 10^{- 6}$ . The significance of this contribution is very much concentrated in the context of the whole available phase space, throughout most of which the one-photon-exchange topology is prevalent in turn. It is thus interesting to present branching ratios for only parts of the allowed kinematical region. We find, for instance, $B (K^{+} \to π^{+} 4 e, m_{4 e} > 150 MeV) = 6.0 (6) \times 10^{- 11}$ .

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Phys. Rev. D 106, L071301– Published 10 October, 2022

Vol. 106, Iss. 7 — 1 October 2022

Received 22 July 2022
Accepted 25 August 2022

DOI: https://doi.org/10.1103/PhysRevD.106.L071301

Published by the American Physical Society under the terms of the Creative Commons Attribution 4.0 International license. Further distribution of this work must maintain attribution to the author(s) and the published article’s title, journal citation, and DOI. Funded by SCOAP³.

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Standard Model estimate of $K^{+} \to π^{+} 4 e$ branching ratio

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Standard Model estimate of K+→π+4e branching ratio

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Standard Model estimate of $K^{+} \to π^{+} 4 e$ branching ratio