Abstract— <p>The OKA Collaboration has obtained a new upper limit on the <i>K</i><sup>+</sup> → π<sup>0</sup>π<sup>0</sup>π<sup>0</sup><i>e</i><sup>+</sup>ν decay probability which is 65 times lower than the one currently listed by PDG. However it is still about 10<sup>4</sup>&#xa0;times worse than the theoretical prediction. It was suggested that production of pionium <i>A</i><sub>2π</sub> in the final state of the semileptonic <i>K</i><sup>+</sup> decay with subsequent <i>A</i><sub>2π</sub> → π<sup>0</sup>π<sup>0</sup> decay will increase the value of theoretical branching ratio due to the absence of five-particle phase space suppression. We demonstrate that despite the gain in the phase space the decay <i>K</i><sup>+</sup> → <i>A</i><sub>2π</sub>π<sup>0</sup><i>e</i><sup>+</sup>ν appears to be strongly suppressed because of the smallness of the pionium wave function at zero π mesons separation.</p>

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On the K+ → π0π0π0e+ν Decay

  • E. K. Karkaryan,
  • K. V. Kiselev,
  • V. F. Obraztsov,
  • I. V. Surkov,
  • M. I. Vysotsky

摘要

Abstract—

The OKA Collaboration has obtained a new upper limit on the K+ → π0π0π0e+ν decay probability which is 65 times lower than the one currently listed by PDG. However it is still about 104 times worse than the theoretical prediction. It was suggested that production of pionium A in the final state of the semileptonic K+ decay with subsequent A → π0π0 decay will increase the value of theoretical branching ratio due to the absence of five-particle phase space suppression. We demonstrate that despite the gain in the phase space the decay K+Aπ0e+ν appears to be strongly suppressed because of the smallness of the pionium wave function at zero π mesons separation.