Measurement of the absolute branching fraction of the inclusive semileptonic ${\mathrm{\Lambda }}_c^{+}$ decay

Using a data sample corresponding to an integrated luminosity of 567 pb${}^{-1}$ collected at a center-of-mass energy of $\sqrt{s}=4.6$ GeV with the BESIII detector, we measure the absolute branching fraction of the inclusive semileptonic ${\mathrm{\Lambda }}_c^{+}$ decay with a double-tag method. We obtain $\mathcal{B}({\mathrm{\Lambda }}_c^{+}\to X{e}^{+}{\nu }_e)=(3.95\pm 0.34\pm 0.09)\mathrm{\%}$, where the first uncertainty is statistical and the second systematic. Using the known ${\mathrm{\Lambda }}_c^{+}$ lifetime and the charge-averaged semileptonic decay width of nonstrange charmed measons ($D^0$ and $D^{+}$), we obtain the ratio of the inclusive semileptonic decay widths $\Gamma(\Lambda_c^+ \rightarrow X e^+ \nu_e)/\bar{\Gamma}(D\rightarrow X e^+ \nu_e)= 1.26\pm0.12$.