Correlated ${\Lambda }_c^{+}{\overline{\Lambda }}_c^{-}$ production in $e^{+}{e}^{-}$ annihilations at $\sqrt{s}\sim 10.5\hspace{0.5em}\mathrm{GeV}$

Using 13.6 ${\mathrm{fb}}^{-1}$ of continuum two-jet $e^{+}{e}^{-}\to c\overline{c}$ events collected with the CLEO detector, we have searched for baryon number correlations at the primary quark level. We have measured the likelihood for a ${\Lambda }_c^{+}$ charmed baryon to be produced in the hemisphere opposite a ${\overline{\Lambda }}_c^{-}$ relative to the likelihood for a ${\Lambda }_c^{+}$ charmed baryon to be produced opposite an anticharmed meson $\overline{D};$ in all cases, the reconstructed hadrons must have momentum greater than 2.3 $\mathrm{GeV}/c.\mathrm{}$ We find that, given a ${\overline{\Lambda }}_c^{-}$ (reconstructed in five different decay modes), a ${\Lambda }_c^{+}$ is observed in the opposite hemisphere $(0.72\mathrm{}\pm 0.11)\%$ of the time (not corrected for efficiency). By contrast, given a $\overline{D}$ in one hemisphere, a ${\Lambda }_c^{+}$ is observed in the opposite hemisphere only $(0.21\mathrm{}\pm 0.02)\%$ of the time. Normalized to the total number of either ${\overline{\Lambda }}_c^{-}$ or $\overline{D}$ “tags,” it is therefore $3.52\pm 0.45\pm 0.42$ times more likely to find a ${\Lambda }_c^{+}$ opposite a ${\overline{\Lambda }}_c^{-}$ than a $\overline{D}$ meson. This enhancement is not observed in the JETSET 7.3 $e^{+}{e}^{-}\to c\overline{c}$ Monte Carlo simulation.