Recent results on Kaon decays from NA48/2

The first observation of the K^± → π^±π⁰e⁺e⁻ rare decay by the NA48/2 experiment at CERN SPS is reported, based on ∼ 2 ×10¹¹ K^± decays recorded in 2003-2004. From a sample of 4919 candidates with 4.9% background the branching ratio in the full kinematic region is measured to be BR(K^± → π^±π⁰e⁺e⁻) = (4.24 ±0.14) ×10^{− 6}. The study of the kinematic space shows evidence for a structure dependent contribution in agreement with predictions based on Chiral Perturbation Theory. The CP-violating asymmetry between K⁺ → π⁺π⁰e⁺e⁻ and K⁻ → π⁻π⁰e⁺e⁻ decay rates has been measured, providing an upper limit |A_CP| < 4.82 ×10^{− 2} at 90% CL. The NA48/2 combined measurement of the charged kaon semileptonic form factors, based on 4.4 million K^± → π⁰e^±ν_e and 2.3 million K^± → π⁰µ^±ν_µ events collected in 2004, is presented. This result represents the most precise form factor measurement from a combined K_l ^± ₃ analysis.