Measurement of the absolute branching fractions of ${\Lambda }_{c}^{+}\to \Lambda \eta {\pi }^{+}$ and $\Sigma \left(1385{\right)}^{+}\eta $

We study the decays ${\Lambda }_{c}^{+}\to \Lambda \eta {\pi }^{+}$ and $\Sigma \left(1385{\right)}^{+}\eta $ based on ${\Lambda }_{c}^{+}{\overline{\Lambda }}_{c}^{-}$ pairs produced in ${e}^{+}{e}^{-}$ collisions at a center-of-mass energy of $\sqrt{s}=4.6\text{}\text{}\mathrm{GeV}$, corresponding to an integrated luminosity of $567\text{}\text{}{\mathrm{pb}}^{-1}$. The data sample was accumulated with the BESIII detector at the BEPCII collider. The branching fractions are measured to be $B\left({\Lambda }_{c}^{+}\to \Lambda \eta {\pi }^{+}\right)=\left(1.84±0.21\left(\text{stat}\right)±0.15\left(\text{syst}\right)\right)%$ and $B\left({\Lambda }_{c}^{+}\to \Sigma \left(1385{\right)}^{+}\eta \right)=\phantom{\rule{0ex}{0ex}}\left(0.91±0.18\left(\text{stat}\right)±0.09\left(\text{syst}\right)\right)%$, constituting the most precise measurements to date.