STUDY OF THE RARE DECAY K± → π±γγ AND HIGH PRECISION MEASUREMENT OF THE FORM FACTORS OF THE SEMILEPTONIC DECAYS K± → π0ℓ±ν

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.