QCD Tests at the NA48/2 experiment at CERN

Abstract

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 ± → π 0 π 0 π ± ( K 3 π ) and K ± → π + π − e ± ν ( K e 4 ) decays give complementary approaches to the study of low energy ππ scattering. From data samples of ∼60 millions K 3 π and ∼1 million K e 4 decays, precise values of a 0 and a 2 , 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.