SpringerOpen, The European Physical Journal C, 10(80), 2020
DOI: 10.1140/epjc/s10052-020-08447-0
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AbstractWe report the first measurement of the absolute branching fraction of the inclusive decay$Λ _c^+ → K_S^0X$Λc+→KS0X. The analysis is performed using an$e^+e^-$e+e-collision data sample corresponding to an integrated luminosity of 567 $\hbox {pb}^{-1}$pb-1taken at$\sqrt{s}$s= 4.6 GeV with the BESIII detector. Using eleven Cabibbo-favored${\bar{\Lambda }}_c^-$Λ¯c-decay modes and the double-tag technique, this absolute branching fraction is measured to be${\mathcal {B}}(Λ _c^+ → K_S^0X)=(9.9± 0.6± 0.4)\%$B(Λc+→KS0X)=(9.9±0.6±0.4)%, where the first uncertainty is statistical and the second systematic. The relative deviation between the branching fractions for the inclusive decay and the observed exclusive decays is$(18.7± 8.3)\%$(18.7±8.3)%, which indicates that there may be some unobserved decay modes with a neutron or excited baryons in the final state.