Improved measurement of the branching fractions of the inclusive decays $D^{+}\to K_S^{0}X$ and $D^0\to K_S^{0}X$

By analyzing 2.93 fb${}^{-1}$ of $e^{+}{e}^{-}$ collision data taken at the center-of-mass energy of 3.773 GeV with the BESIII detector, the branching fractions of the inclusive decays $D^{+}\to K_S^{0}X$ and $D^0\to K_S^{0}X$ are measured to be $(32.78\pm 0.13\pm 0.27)\mathrm{\%}$ and $(20.54\pm 0.12\pm 0.18)\mathrm{\%}$, respectively, where the first uncertainties are statistical and the second are systematic. These results are consistent with the world averages of previous measurements, but with improved precision.