A new measurement of Re(ε′/ε) by the NA48 experiment at CERN and future plans

Abstract

The NA48 experiment at CERN detects concurrently the four decay modes into two pions of the long and short lived neutral kaons. During 1998 and 1999 data taking, statistics in each mode was increased by a factor eight, with respect to the 1997 published data. A new measurement of the double ratio of the four modes has been obtained from these data. This new result on the direct CP violation parameter Re(ε′/ε) is (15.0 ± 2.7) × 10 −4 which, combined with the previous NA48 published result gives Re(ε′/ε) = (15.3 ± 2.6) × 10 −4