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

TL;DR

This study investigates how the production of $K^0$, $b4$, and $b1^-$ mesons depends on the atomic mass number in neutrinonuclear reactions, revealing nuclear enhancement effects and the role of intranuclear interactions.

Contribution

First measurement of the A-dependence of $K^0$, $b4$, and $b1^-$ production in neutrinonuclear reactions using SKAT data, with a model explaining the nuclear effects.

Findings

A-dependence parameter for $V^0$ particles is 0.20 b1 0.05.

The $K^0/\pi^-$ ratio increases with A, reaching 0.099 b1 0.011 at A b1 45.

Intranuclear interactions account for about 29% of the $K^0$ yield increase at A b1 45.

Abstract

For the first time, the A- dependence of the production of $K^0$, $\Lambda$ and, for comparison, $\pi^-$ mesons is investigated in neutrinonuclear reactions, using the data obtained with SKAT bubble chamber. An exponential parametrization ($\sim A^{\beta}$) of the particle yields results in ${\beta}_{V^0} = 0.20 \pm 0.05$ for $V^0$ particles (combined $K^0$ and $\Lambda$), while for $\pi^-$ mesons the A- dependence is much weaker, ${\beta}_{\pi^-} = 0.068 \pm 0.007$. A nuclear enhancement of the ratio $K^0/\pi^-$ is found; this ratio increases from $0.055 \pm 0.013$ for $\nu N$- 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 ${\Lambda}^0$ and $\pi^-$ yields can be reproduced in the framework of a model, incorporating the secondary intranuclear interactions of pions originating from the primary $\nu N$- interactions, while only (29$\pm$9)% of that for $K^0$ at $A \approx 45$ can be attributed to intranuclear interactions.