Study of the rare decay $K^{\pm} \rightarrow \pi^{\pm}\gamma\gamma$ and high precision measurement of the form factors of the semileptonic decays $K^{\pm} \rightarrow \pi^{0}\ell^{\pm}\nu$

The NA48/2 experiment presents preliminary measurements of the form factors of the charged kaon semileptonic decays. The Ke3 and Kμ3 results are in good agreement allowing for a combined result which matches the precision of the current world average on the vector and scalar form factors. Recent study of the rare decay K± → π±γγ from the NA48/2 and NA62 data samples is also reported.