The A - dependence of $K^{0}$ and $Λ$ neutrinoproduction on nuclei

Abstract

For the first time, the A- dependence of the production of $K^0$, $Λ$ and, for comparison, $π^-$ mesons is investigated in neutrinonuclear reactions, using the data obtained with SKAT bubble chamber. An exponential parametrization ($\sim A^β$) of the particle yields results in $β_{V^0} = 0.20 \pm 0.05$ for $V^0$ particles (combined $K^0$ and $Λ$), while for $π^-$ mesons the A- dependence is much weaker, $β_{π^-} = 0.068 \pm 0.007$. A nuclear enhancement of the ratio $K^0/π^-$ is found; this ratio increases from $0.055 \pm 0.013$ for $νN$- interactions up to $0.070 \pm 0.011$ at $A \approx 21$ and $0.099 \pm 0.011$ at $A \approx 45$. It is observed, that the multiplicity rise of $V^0$'s occures predominantely in the backward hemisphere of the hadronic c.m.s. It is shown, that the A- dependence of the nuclear enhancement of the $Λ^0$ and $π^-$ yields can be reproduced in the framework of a model, incorporating the secondary intranuclear interactions of pions originating from the primary $νN$- interactions, while only (29$\pm$9)% of that for $K^0$ at $A \approx 45$ can be attributed to intranuclear interactions.