Latest results from NA48 and NA48/1.

Abstract

The first observations of the rare decays KS ! 0e+e− and KS ! 0μ+μ− have been made by the NA48/1 collaboration at the CERN SPS accelerator. From high intensity KS data collected during the 2002 run, clean signals of 7 KS ! 0e+e− events and 6 KS ! 0μ+μ− events were observed, giving branching ratio measurements of BR(KS ! 0e+e−) = 5.8+2.9 −2.4 × 10−9 and BR(KS ! 0μ+μ−) = 2.9+1.5 −1.2 × 10−9. These results constrain the indirect CP violating component of the corresponding KL decays. Other recent results from NA48 are also presented.