Abstract: The $K^+ \rightarrow \pi^+ \nu \bar{\nu}$ decay is a golden mode for flavour physics. Its branching ratio is predicted with a high precision by the Standard Model to be less than $\mathcal{O}(10^{-10})$. This decay mode is highly sensitive to indirect effects of new physics up to the highest mass scales. The NA62 experiment at the CERN SPS is designed to study the $K^+ \rightarrow \pi^+ \nu \bar{\nu}$ decay, and provided the world’s most precise investigation of this decay using 2016-18 data. Building on this success, the first results from a significantly improved analysis of new data, taken in 2021-22 after beam-line and detector upgrades, are presented, as well as the combination with the 2016-18 results.
