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Compositeness of the strange, charm and beauty odd parity $Λ$ states

We study the dependence on the quark mass of the compositeness of the lowest-lying odd parity hyperon states. Thus, we pay attention to $Λ-$like states in the strange, charm and beauty, sectors which are dynamically generated using a unitarized meson-baryon model. In the strange sector we use an SU(6) extension of the Weinberg-Tomozawa meson-baryon interaction, and we further implement the heavy-quark spin symmetry to construct the meson-baryon interaction when charmed or beauty hadrons are involved. In the three examined flavor sectors, we obtain two $J^P=1/2^-$ and one $J^P=3/2^-$ $Λ$ states. We find that the $Λ$ states which are bound states (the three $Λ_b$) or narrow resonances (one $Λ(1405)$ and one $Λ_c(2595)$) are well described as molecular states composed of $s$-wave meson-baryon pairs. The $\frac{1}{2}^-$ wide $Λ(1405)$ and $Λ_c(2595)$ as well as the $\frac{3}{2}^-$ $Λ(1520)$ and $Λ_c(2625)$ states display smaller compositeness and so they would require new mechanisms, such as $d$-wave interactions.