High precision study of CP-violating charge asymmetry in K+- --> 3pi+- decays

Abstract

A precise measurement of the direct CP violating charge asymmetry parameter $A_g$ in $K^\pm\toπ^\pmπ^+π^-$ decays by the NA48/2 experiment at CERN SPS is presented. The experiment has been designed not to be limited by systematic uncertainties in the asymmetry measurement. A preliminary result for the charge asymmetry $A_g=(-1.3\pm2.3)\times 10^{-4}$ has been obtained with a sample of $3.11\times 10^9$ selected events corresponding to the full collected statistics. The precision of the result is limited by the statistics used.