CPViolation in NonleptonicK0Decays

The nonleptonic $K^0$ decays are examined on the basis of the $\mathrm{CPT}$ theorem and unitary symmetry without the requirement of $\mathrm{CP}$ invariance. It is shown that the present model (based on the $\mathrm{CPT}$ theorem and unitary symmetry) is consistent with the various experimental branching ratios of $K\to 2\pi$ modes, if $\mathrm{CP}$ invariance is almost maximally violated. Further, the decays $K_1^{}{}_{}{}^0\to 3{\pi }^0$ and $K_2^{}{}_{}{}^0\to 3{\pi }^0$ are forbidden by unitary symmetry in the framework of the boson pole model, even if $\mathrm{CP}$ invariance is violated.