  We study the reactions $J/\psi\to\bar{\Lambda}K^-p$ and
$J/\psi\to\bar{\Lambda}\pi^+\pi^-\Lambda$ with a unitary chiral approach. We
predict the ratio of the invariant mass distributions of these two reactions at
the $\Lambda(1520)$ peak position, which is free of the unknown production
mechanism and reflects only the properties of the $\Lambda(1520)$. An
experimental measurement of this ratio will provide the couplings of the
$\Lambda(1520)$ to its decay channels, allowing to test the predictions of the
chiral unitary approach on this resonance, which appears as dynamically
generated in that approach.
