Measurement of the branching ratio of the $K^{+}\rightarrow\pi^{+}\nu\bar{\nu}$ decay

NA62 Collaboration

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arXiv · 2607.16413

Measurement of the branching ratio of the $K^{+}\rightarrow\pi^{+}\nu\bar{\nu}$ decay

NA62 Collaboration

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Abstract

The NA62 experiment has measured the branching ratio of the rare decay $K^+\to\pi^+\nu\bar{\nu}$ using data collected in 2023 and 2024 at the CERN SPS, obtaining ${\rm B}_{\rm 2023-2024}(K^+\to\pi^+\nu\bar{\nu}) = \left(7.2^{+2.3}_{-2.1}\right)\times10^{-11}$. With results from data collected between 2016 and 2022, the analysis gives ${\rm B}_{\rm 2016-2024}(K^+\to\pi^+\nu\bar{\nu}) = \left(9.6^{+1.9}_{-1.8}\right)\times10^{-11}$, corresponding to a relative precision of $20\%$. This value is consistent with Standard Model predictions.

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NA62 Collaboration. 2026-07-17. Measurement of the branching ratio of the $K^{+}\rightarrow\pi^{+}\nu\bar{\nu}$ decay. https://arxiv.org/abs/2607.16413

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