Latest results on the direct CP violation measurements - var-epsilon '/var-epsilon

Preliminary results, based on the full data sample from Fermilab-E731 and the combined data sample from CERN-NA31, on the 'direct' CP-violation measurements var-epsilon '/var-epsilon in neutral kaon decay have been reviewed. The E731's result is Re(var-epsilon '/var-epsilon) = (6.0 ± 5.8(stat) ± 3.2(syst) ± 1.8(MC)) x 10-4, which provides no evidence for 'direct' CP-violation, thus supporting the Superweak model; while the NA31's combined result ('86+'88+'89 data) is Re(var-epsilon '/var-epsilon) = (23 ± 3.4(stat) ± 6.5(syst) )x 10-4, three standard deviations from zero, which provides evidence for the 'direct' CP-violation in the Standard Model. Comparisons of the two experiments are made. The Fermilab-E731 group has also fit for the other parameters of the neutral kaon system in their 2π data sample, such as: the KS life time τS; the KL-KS mass difference Δm; the phase difference between η00 and η±, Δφ = (- 0.6 ± 1.6)degrees, which is a test of CPT invariance; the Superweak phase φSW = (43.37 ± 0.22)degrees, and the phase of η±, φ± = (43.2 ± 1.6)degrees, which is predicted by CPT invariance to equal φSW. 18 refs., 26 figs., 9 tabs