Factorization Contributions and the Breaking of the $\Delta I=1/2$ Rule in Weak $\Lambda N\rho$ and $\Sigma N\rho$ Couplings

Abstract

We compute the modified factorization contributions to the $\Lambda\rightarrow N\rho$ and $\Sigma\rightarrow N\rho$ couplings and demonstrate that these contributions naturally include $\Delta I=3/2$ terms which are comparable ($\simeq 0.4$ to $-0.8$ times) in magnitude to the corresponding $\Delta I=1/2$ terms. As a consequence, we conclude that models which treat vector meson exchange contributions to the weak conversion process $\Lambda N\rightarrow NN$ assuming such weak couplings to satisfy the $\Delta I=1/2$ rule are unlikely to be reliable.