Observation or the $B_s$ Meson at the $\Upsilon(5S)$

Using the CLEO detector at the Cornell Electron Storage Ring, we have observed the $B_s$ meson in $e^+ e^-$ annihilation at the $\Upsilon(5S)$ resonance. We have established that at the energy of the $\Upsilon(5S)$ resonance $B_s$ production proceeds predominantly through the creation of $B_s^{*} \bar{B}_s^{*}$ pairs. We find $\sigma(e^+e^- \rightarrow B_s^*\bar{B}_s^*) = [0.11^{+0.04}_{-0.03}{\rm (stat.)} \pm 0.02 {\rm (syst.)}] \; {\rm nb}$. The mass of the $B_s^*$ meson is measured to be $M_{B_s^*} = [ 5.414 \pm 0.001{\rm (stat.)}\pm 0.003{\rm (syst.)}]$~GeV/$c^2$.