Limits on variances from symmetry in neutral kaon decays

An analysis is made of the limits on the possible departures from CP-, T-, and TCP- invariance, both in the structure of K/sub L/ and K/sub S / states and in the decay amplitudes to pi pi and pi l nu channels. A small violation of the requirements of CP- and T-invariance on the structure of K/sub L/ and K/sub S/ states can be deduced under quite plausible assumptions, but there is no evidence of any other departure from the requirements of CP-, or T-, or TCP-invariance. However, the present limit for one measure delta of TCP-noninvariance is several times larger than the estimated value of the corresponding CP- and T- noninvariance parameter sigma =Re(K/sub L/ mod K/sub s/). Taking a conservative view of the experimental data, symmetry-violating parts of 2 pi decay amplitudes are limited to better than 1% for the I=0 channel and to within a small percentage for the I=2 channel, in relative magnitude. The corresponding limits which can be deduced for leptonic decay amplitudes are somewhat larger but there are indications that symmetry-violating amplitudes are unlikely to exceed a small percentage in relative magnitude. (31 refs).