Measurement of the absolute branching fraction of the inclusive semileptonic $\hat{I}{›}_c^{+}$ decay

Abstract

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 $\hat{I}{›}_c^{+}$ decay with a double-tag method. We obtain $\mathcal{B}(\hat{I}{›}_c^{+}\to X{e}^{+}\hat{I}{½}_e)=(3.95\pm 0.34\pm 0.09)\%$, where the first uncertainty is statistical and the second systematic. Using the known $\hat{I}{›}_c^{+}$ 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 $\hat{I}“(\hat{I}{›}_c^{+}\to X{e}^{+}\hat{I}{½}_e)/\bar{\hat{I}}“(D\to X{e}^{+}\hat{I}{½}_e)=1.26\pm 0.12$.

7 pages, 3 figures