Search for $K^{+}$ decays to a muon and invisible particles

NA62 collaboration

The NA62 experiment at CERN reports searches for $K^{+}\to {\mu }^{+}N$ and $K^{+}\to {\mu }^{+}\nu X$ decays, where $N$ and $X$ are massive invisible particles, using the 2016-2018 data set. The $N$ par…