Improved measurement of the absolute branching fraction of inclusive semileptonic ${\Lambda }_{c}^{+}$ decay

Using $4.5\text{}\text{}{\mathrm{fb}}^{-1}$ of ${e}^{+}{e}^{-}$ annihilation data samples collected at center-of-mass energies ranging from 4.600 to 4.698 GeV with the BESIII detector at the BEPCII collider, we measured the absolute branching fraction for the inclusive semileptonic decay ${\Lambda }_{c}^{+}\to X{e}^{+}{\nu }_{e}$, where $X$ refers to any possible particle system. The branching fraction of the decay is determined to be $B\left({\Lambda }_{c}^{+}\to X{e}^{+}{\nu }_{e}\right)=\left(4.06±0.1{0}_{\mathrm{stat}}±0.0{9}_{\mathrm{syst}}\right)%$. Our result improves the precision of previous measurements of $B\left({\Lambda }_{c}^{+}\to X{e}^{+}{\nu }_{e}\right)$ by more than threefold. Using the known ${\Lambda }_{c}^{+}$ lifetime and the charge-averaged semileptonic decay width of nonstrange charmed mesons, we measure the ratio of inclusive semileptonic decay widths $\Gamma \left({\Lambda }_{c}^{+}\to X{e}^{+}{\nu }_{e}\right)/\overline{\Gamma }\left(D\to X{e}^{+}{\nu }_{e}\right)=1.28±0.05$, where statistical and systematic uncertainties are combined.