NEW NA48/2 RESULTS ON RARE KAON DECAYS

NA48/2 results related to ChPT testing are presented. The most precise measurement of the charged kaon semileptonic form factors has been obtained from 4.4 x 10(6) the K-+/- -> pi(0)e(+/-)nu(e) (K-e3(+/-)) and 2.91 x 106 the K-+/- -> pi(0)mu(+/-)nu(mu) (K-mu 3(+/-)) events collected in 2004. In addition, the branching ratio of the K-+/- -> pi(+/-)pi(0)e(+)e(-) decay, that has not been observed so far, has been obtained from a sample of 4919 decay candidates with 4:9% background. The branching ratio in the full kinematic region is measured to be (4.24 +/- 0.15) x 10(-6), which is in agreement with ChPT predictions.