Interactions of NeutralKMesons in Hydrogen

The reaction ${\pi }^{-}+p\to \Lambda +K^0$ in the 72-in. hydrogen chamber was used to produce 7220 $K^0$ mesons associated with a visible decay $\Lambda \to p+{\pi }^{-}$. The time dependence and absolute yield of the subsequent strong interactions of $K^0$ and $K^0$ in hydrogen were used to determine all the parameters of the neutral $K$ system, without the assumption of $\mathrm{CPT}$ invariance or other assumptions about the weak interactions of neutral $K$'s. From the time distribution of 59 events of the type ${\overline{K}}^0+p\to \mathrm{hyperon}$, we find the magnitude of the $K_S^0-K_L^0$ mass difference. We then determine the mixing parameters $p$, $q$, $p^{\prime }$, $q^{\prime }$ of the neutral $K$ system by means of the time dependence and absolute yield of 11 charge-exchange events, $K^0+p\to K^{+}+n$, and the absolute yield of 49 two-body interactions, ${\overline{K}}^0+p\to \mathrm{hyperon}+\mathrm{pion}$. The results are consistent with $\mathrm{CPT}$ invariance and with values of the mixing parameters determined by means of weak interactions. We find the Biswas ratio $R\equiv \frac{\sigma (K_{L}p\to K_{S}p)}{\sigma (K_{L}p\to \mathrm{hyperon})}$ to be $R=0.41\mathrm{}\pm 0.13$ averaged over $K_L$ momenta from about 200 to 600 $\frac{\mathrm{MeV}}{c}$. This agrees with solution I of Kim and with the results of Kadyk et al. Our absolute yields for ${\overline{K}}^0+p\to \mathrm{hyperon}+\mathrm{pion}$ are in good agreement with the predictions of charge independence and the measured rates for $K^{-}+p\to \mathrm{hyperon}+\mathrm{pion}$. For the front-back asymmetry of the $\Lambda$ in ${\overline{K}}^0+p\to \Lambda +{\pi }^{+}$, we find $\frac{\mathrm{}(F-B)\mathrm{}}{\mathrm{}(F+B)=-0.48\mathrm{}\pm 0.18}$, indicating that the $P$ wave cannot be neglected relative to the $S$ wave in our momentum range.