NA48/62 latest results

The NA62 experiment at the CERN SPS recorded in 2007 a large sample of $K^+ \rightarrow \mu^+ \nu_\mu $ decays. A peak search in the missing mass spectrum of this decay is performed. In the absence of observed signal, the limits obtained on $\mathcal{B}(K^+ \rightarrow \mu^+ \nu_h )$ and on the mixing matrix element $|U_{\mu4}|$ are reported. The upgraded NA62 experiment started data taking in 2015. About 5$\times 10^{11} K^+$ decays have been recorded so far to measure the branching ratio of the $K^+ \rightarrow \pi^+ \nu\overline{\nu}$ decay. Preliminary results from the $K^+ \rightarrow \pi^+ \nu\overline{\nu}$ analysis based on about 5$\%$ of the 2016 statistics are reported.