Roles of $a_0(980)$, $Λ(1670)$, and $Σ(1385)$ in the $Λ_c^+ \to ηΛπ^+$ decay

Abstract

Recently, the Belle Collaboration has measured the $Λ_c^+ \to ηΛπ^+$ decay and reported the $ηΛ$ and $Λπ^+ $ invariant mass distributions, which show the clear signals of the resonances $Λ(1670)$ and $Σ(1385)$, respectively. Based on our previous works [Eur. Phys. J. C 76 (2016) 496 and Phys. Rev. D 95 (2017) 074024], we re-analyze this process by considering the $S$-wave $ηΛ$ and $ηπ^+$ final state interactions within the chiral unitary approach, which dynamically generate the $Λ(1670)$ and $a_0(980)$, respectively. Our results are in good agreement with the Belle measurements, which supports the molecular nature of the $Λ(1670)$ and $a_0(980)$. In addition, the $ηπ^+$ invariant mass distributions are also computed and a cusp structure of $a_0(980)$ is cleary shown around the $K\bar{K}$ mass threshold.