First search for $K^+\rightarrow\pi^+\nu\bar{\nu}$ using the decay-in-flight technique

NA62 collaboration

doi:10.1016/j.physletb.2019.01.067

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arXiv · 1811.08508

First search for $K^+\rightarrow\pi^+\nu\bar{\nu}$ using the decay-in-flight technique

NA62 collaboration

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Abstract

The NA62 experiment at the CERN SPS reports the first search for $K^+ \rightarrow \pi^+ \nu \bar{\nu}$ using the decay-in-flight technique, based on a sample of $1.21\times10^{11}$ $K^+$ decays collected in 2016. The single event sensitivity is $3.15\times 10^{-10}$, corresponding to 0.267 Standard Model events. One signal candidate is observed while the expected background is 0.152 events. This leads to an upper limit of $14 \times 10^{-10}$ on the $K^+ \rightarrow \pi^+ \nu \bar{\nu}$ branching ratio at 95\% CL.

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NA62 collaboration. 2018-11-20. First search for $K^+\rightarrow\pi^+\nu\bar{\nu}$ using the decay-in-flight technique. https://doi.org/10.1016/j.physletb.2019.01.067

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