K−3πDecay andK20−K10Mass Difference on Current-Current Picture

Some consequences of the current-current picture are considered in connection with $K-3\mathrm{}\pi$ decay and the ${K_2}^0-{K_1}^0$ mass difference. It is shown that this picture in boson pole approximation can explain both the decay rates and spectra for the $3\pi$ decay modes of $K$. The ${K_2}^0-{K_1}^0$ mass difference is considered in terms of a boson pole approximation and a two-pion intermediate state. The relevant weak-coupling constants are estimated on the current-current picture. It is shown that the sign of the mass difference ($\delta m=\delta {m_{K2\mathrm{}}}^0-\delta {m_{K1\mathrm{}}}^0$) is positive, which is in agreement with recent experimental indications. The magnitude is somewhat small but it is not excluded by the present experimental situation.