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Interactions of NeutralKMesons in Hydrogen

Physical review. D. Particles, fields, gravitation, and cosmology/Physical review. D. Particles and fields1971Vol. 3(11), pp. 2553–2560

Gerald W. Meisner, Frank S. Crawford

Abstract

The reaction ${\ensuremath{\pi}}^{\ensuremath{-}}+p\ensuremath{\rightarrow}\ensuremath{\Lambda}+{K}^{0}$ in the 72-in. hydrogen chamber was used to produce 7220 ${K}^{0}$ mesons associated with a visible decay $\ensuremath{\Lambda}\ensuremath{\rightarrow}p+{\ensuremath{\pi}}^{\ensuremath{-}}$. 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 ${\overline{K}}^{0}+p\ensuremath{\rightarrow}\mathrm{hyperon}$, we find the magnitude of the ${K}_{S}^{0}\ensuremath{-}{K}_{L}^{0}$ mass difference. We then determine the mixing parameters $p$, $q$, ${p}^{\ensuremath{'}}$, ${q}^{\ensuremath{'}}$ of the neutral $K$ system by means of the time dependence and absolute yield of 11 charge-exchange events, ${K}^{0}+p\ensuremath{\rightarrow}{K}^{+}+n$, and the absolute yield of 49 two-body interactions, ${\overline{K}}^{0}+p\ensuremath{\rightarrow}\mathrm{hyperon}+\mathrm{pion}$. 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 $R\ensuremath{\equiv}\frac{\ensuremath{\sigma}({K}_{L}p\ensuremath{\rightarrow}{K}_{S}p)}{\ensuremath{\sigma}({K}_{L}p\ensuremath{\rightarrow}\mathrm{hyperon})}$ to be $R=0.41\ifmmode\pm\else\textpm\fi{}0.13$ 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 ${\overline{K}}^{0}+p\ensuremath{\rightarrow}\mathrm{hyperon}+\mathrm{pion}$ are in good agreement with the predictions of charge independence and the measured rates for ${K}^{\ensuremath{-}}+p\ensuremath{\rightarrow}\mathrm{hyperon}+\mathrm{pion}$. For the front-back asymmetry of the $\ensuremath{\Lambda}$ in ${\overline{K}}^{0}+p\ensuremath{\rightarrow}\ensuremath{\Lambda}+{\ensuremath{\pi}}^{+}$, we find $\frac{(F\ensuremath{-}B)}{(F+B)=\ensuremath{-}0.48\ifmmode\pm\else\textpm\fi{}0.18}$, indicating that the $P$ wave cannot be neglected relative to the $S$ wave in our momentum range.

Abstract

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