Measurement of B(Λc+→pK-π+)

The ${\Lambda }_c^{+}\to {\mathrm{pK}}^{-}{\pi }^{+}$ yield has been measured in a sample of two-jet continuum events containing both a charm tag $\left(“\overline{D}”\right)$ as well as an antiproton ${(e}^{+}{e}^{-}\to \overline{D}\overline{p}\mathrm{X}),$ with the antiproton in the hemisphere opposite the $\overline{D}$ (measurement of charge conjugate modes is implicit throughout). Under the hypothesis that such selection criteria tag $e^{+}{e}^{-}\to \overline{D}\overline{p}{\Lambda }_c^{+}\mathrm{X}$ events, the ${\Lambda }_c^{+}\to {\mathrm{pK}}^{-}{\pi }^{+}$ branching fraction can be determined by measuring the ${\mathrm{pK}}^{-}{\pi }^{+}$ yield in the same hemisphere as the antiprotons in our $\overline{D}\overline{p}\mathrm{X}$ sample. Three types of $\overline{D}$ charm tags are used, ${\pi }_{\mathrm{soft}}^{-}$ (from $D^{*-}\to D^0{\pi }_{\mathrm{soft}}^{-}),$ electrons (from $\overline{D}\to {\mathrm{Xe}}^{-}\nu ),$ and fully reconstructed $D^0\to K^{+}{\pi }^{-}$ or $D^{-}\to K^{+}{\pi }^{-}{\pi }^{-}$ or $D_{\mathrm{s}}^{-}\to \phi {\pi }^{-}.$ Combining our results obtained from the three independent charm tags, we obtain $\mathcal{B}({\Lambda }_c^{+}\to {\mathrm{pK}}^{-}{\pi }^{+})=(5.0\mathrm{}\pm 0.5\pm 1.2)\%.$