New measurement of direct CP violation parameter Re(ε[sup ʹ]/ε) by the NA48 experiment at CERN

Abstract

The NA48 experiment at CERN detects concurrently the four decay modes of the long and short lived neutral kaons. During 1998 data taking, statistics in each mode was increased by at least a factor two, with respect to the 1997 published data. A new measurement of the double ratio of the four modes has been obtained from these data. The new preliminary result on the direct CP violation parameter Re(e′/e) is (12.2±4.9)×10−4 which, combined with the NA48 published result gives Re(e′/e)=(14.0±4.3)×10−4.