QCD Tests at the NA48/2 experiment at CERN Original Research Article

Very large statistics of charged kaon decays have been accumulated in 2003-2004 by the NA48/2 experiment at the CERN SPS. The analyses of K±→π0π0π±(K3π) and K±→π+π−e±ν(Ke4) decays give complementary approaches to the study of low energy ππ scattering. From data samples of ∼60 millions K3π and ∼1 million Ke4 decays, precise values of a0 and a2, the isospin 0 and 2 S-wave ππ scattering lengths, can be extracted with an unprecedented experimental precision of few percents, allowing accurate tests of Chiral Perturbation Theory predictions.