CP Violation results from the NA48 experiments

Abstract

The main goal of the NA48 experiments at the CERN SPS has been the search for direct CP violation (CPV) in neutral and charged kaon decays. In this paper selected results on CPV from the NA48 and NA48/2 experiments are presented. The direct CPV parameter Re(ε′/ε) has been measured by NA48 from the decay rates of neutral kaons into two pions. In the charged kaon sector, NA48/2 has measured the asymmetry Ag of the linear slope parameter g in the Dalitz plot of K± → 3π decays. Thanks to the high statistics collected in 2003 and 2004, further CPV studies were performed in several kaon decays. Results on CPV studies in K± → π±π0γ K± → π±e+e− and K± → π±μ+μ− decays will be presented, as well as in the KS → π+π−e+e− decay.