We report measurements from the CLEO detector of the rate of $\Xi$ and $\Lambda$ production in $e^{+}{e}^{-}$ interactions in the upsilon region. Hyperon production from the decay of the $\Upsilon \mathrm{}\left(1s\right)\mathrm{}$ is compared with continuum $e^{+}{e}^{-}$ data. The ratio of the production rates of $\Lambda$ (and $\bar{\Lambda }$) to $K^0$ (and ${\bar{K}}^0$) on the $\Upsilon \mathrm{}\left(1s\right)\mathrm{}$ is 0.21 ± 0.03, much larger than in the continuum, 0.07 ± 0.01. The ratios of the production rates of the $\Xi$ and $\Lambda$ are comparable, $0.10\pm 0.02 \left[\Upsilon \mathrm{}\right(1S\left)\right]$ and 0.07 ± 0.02 (continuum). We discuss some implications of the data for gluon and quark fragmentation models.

• Received 12 April 1984

DOI:https://doi.org/10.1103/PhysRevLett.53.24