Unitary coupled channel analysis of the $\Lambda(1520)$ resonance

Abstract

We study the $\Lambda(1520)$ resonance in a coupled channel approach involving the $\pi\Sigma(1385)$, $K\Xi(1530)$, $\bar{K}N$ and $\pi\Sigma$ channels. Implementing unitarity in coupled channels, we make an analysis of the relative importance of the different mechanisms which contribute to the dynamical structure of this resonance. From experimental information on some partial wave amplitudes and constraints imposed by unitarity, we get a comprehensive description of the amplitudes and hence the couplings to the different channels. We test these amplitudes in different reactions like $K^-p\to\Lambda\pi\pi$, $\gamma p\to K^+K^-p$, $\gamma p\to K^+\pi^0\pi^0\Lambda$ and $\pi^- p\to K^0 K^-p$ and find a fair agreement with the experimental data.