Roles of a0(980) , Λ(1670) , and Σ(1385) in the Λc+→ηΛπ+ decay

Abstract

Recently, the Belle Collaboration has measured the ${\mathrm{\ensuremath{\Lambda}}}_{c}^{+}\ensuremath{\rightarrow}\ensuremath{\eta}\mathrm{\ensuremath{\Lambda}}{\ensuremath{\pi}}^{+}$ decay and reported the $\ensuremath{\eta}\mathrm{\ensuremath{\Lambda}}$ and $\mathrm{\ensuremath{\Lambda}}{\ensuremath{\pi}}^{+}$ invariant mass distributions, which show the clear signals of the resonances $\mathrm{\ensuremath{\Lambda}}(1670)$ and $\mathrm{\ensuremath{\Sigma}}(1385)$, respectively. Based on our previous works [Eur. Phys. J. C 76, 496 (2016) and Phys. Rev. D 95, 074024 (2017)], we reanalyze this process by considering the $S$-wave $\ensuremath{\eta}\mathrm{\ensuremath{\Lambda}}$ and $\ensuremath{\eta}{\ensuremath{\pi}}^{+}$ final state interactions within the chiral unitary approach, which dynamically generate the $\mathrm{\ensuremath{\Lambda}}(1670)$ and ${a}_{0}(980)$, respectively. Our results are in agreement with the Belle measurements of the $\ensuremath{\eta}\mathrm{\ensuremath{\Lambda}}$ and ${\ensuremath{\pi}}^{+}\mathrm{\ensuremath{\Lambda}}$ invariant mass distributions. In addition, the ${\ensuremath{\pi}}^{+}\ensuremath{\eta}$ invariant mass distribution is also calculated and a cusp structure of ${a}_{0}(980)$ is clearly shown around the $K\overline{K}$ mass threshold.