Inclusive ${\eta }^{\prime }$ production from the ${\rm Y}\mathrm{}\left(1S\right)\mathrm{}$

Using the CLEO II detector at CESR, we measure the ${\eta }^{\prime }$ energy spectra in ${\rm Y}\mathrm{}\left(1S\right)\mathrm{}$ decays that we compare with models of the ${\eta }^{\prime }{g}^{*}g$ form factor. This form factor, especially at large ${\eta }^{\prime }$ energies, may provide an explanation of the large rate for $\overrightarrow{B}{X}_s{\eta }^{\prime }.$ Our data do not support a large anomalous coupling at higher $q^2$ and thus the large ${\eta }^{\prime }$ rate remains a mystery, possibly requiring a non-standard-model explanation.