QCD tests at NA48

The main goal of the NA48/2 experiment was to measure the CP violating asymmetry in the charged kaon decay in three pions. Thanks to the very high statistics achieved both in K+ and K− decays, many other interesting measurements has been performed with unprecedented precision. The analysis of the strong interaction dynamics at low energy is one of the main issues studied using kaon decays. In particular, in this paper, the results obtained in p −p scattering lengths measurement will be presented using two different approaches, and the Branching Ratio measurements of K+ →p+gg and K+ →p+e+e−g that are sensitive tests of Chiral Perturbation Theory (ChPT).