Search for CP violation in the decay of tagged and K0 to π0π0π0

The CPLEAR experiment measured the eigentime-dependent asymmetry in the rates of initially tagged K 0 and K 0 decaying to π 0 π 0 π 0 in order to study the interference between the CP-violating K S and the CP-conserving K L decay amplitudes. Without assuming CPT invariance, we obtain for the CP-violation parameter η 000 the values Re( η 000 )=0.18±0.14 stat. ±0.06 syst. and Im( η 000 )=0.15±0.20 stat. ±0.03 syst. . Requiring Re( η 000 ) to be equal to Re(ϵ) we obtain Im( η 000 )=−0.05±0.12 stat. ±0.05 syst. . The corresponding upper limit for the branching ratio of the K S →π 0 π 0 π 0 decay is deduced to be B K S →π 0 π 0 π 0 −5 at the 90% confidence level.