$K^+ \to \pi^+ \nu \overline{\nu}$ - NA62 First Result

The CERN NA62 experiment uses a novel "kaon decay-in-flight" technique to observe $K^+ \to \pi^+ \nu \overline{\nu}$. The preliminary result based on the analysis of the full 2016 dataset will be presented. In agreement with the Standard Model prediction, one candidate was observed. Under the background hypothesis, an upper limit of $14 \times 10^{-10}$ at 95 % C.L. was placed on the branching ratio.