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Upper Limit on the Branching Ratio for the Decay $π^0 \to ν\barν$

E949 Collaboration·A. V. Artamonov
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Abstract

A sample of kinematically identified $K^+ \to π^+ π^0$ decays obtained with the E949 detector was used to search for the helicity-suppressed decay $π^0 \to ν\barν$ resulting in an upper limit of $2.7\times10^{-7}$ at 90% confidence level.The upper limit is also applicable to $π^0$ decays into unknown weakly interacting particles.

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E949 Collaboration, A. V. Artamonov. 2005-10-26. Upper Limit on the Branching Ratio for the Decay $π^0 \to ν\barν$. https://doi.org/10.1103/physrevd.72.091102

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