Evidence for $B_s^{(*)}{\overline{B}}_s^{(*)}$ Production at the ${\rm Y}(5S)$ Resonance

We use data collected by the CLEO III detector at the Cornell Electron Storage Ring to measure the inclusive yields of $D_s$ mesons as $\mathcal{B}\mathbf{(}{\rm Y}(5S)\to D_{s}X\mathbf{)}=(44.7\pm 4.2\pm 9.9)\%$ and $\mathcal{B}\mathbf{(}{\rm Y}(4S)\to D_{s}X\mathbf{)}=(18.1\pm 0.5\pm 2.8)\%$. From these measurements, we make a model dependent estimate of the ratio of $B_s^{(*)}{\overline{B}}_s^{(*)}$ to the total $b\overline{b}$ quark pair production of $(16.0\pm 2.6\pm 5.8)\%$ at the ${\rm Y}(5S)$ energy.

Figure 1

The invariant mass distributions of the $D_s$ candidates with $x<0.5$ from: (a) the ${\rm Y}(4S)$ on-resonance data, (b) the continuum below the ${\rm Y}(4S)$ resonance data, and (c) the ${\rm Y}(5S)$ on-resonance data.

Figure 2

Branching rate as a function of $x$ from ${\rm Y}(5S)$ decays (solid circles) and from ${\rm Y}(4S)$ decays (open circles).

Figure 3

Dominant decay diagrams for a $B$ meson into $D_s$ mesons ($q$ is either a $u$ or $d$ quark).

Figure 4

Dominant decay diagrams for a $B_s$ meson into $D_s$ mesons.