On the determination of the relative probability of ${\rm Y}(5S)\to B_s^{(\ast )}{\bar{B}}_s^{(\ast )}$ decays

Semileptonic decays of the $B\bar{B}$ pairs produced in the ${\rm Y}(5S)$ can be used to find the relative probability of ${\rm Y}(5S)\to B_s{\bar{B}}_s$ decays. This could be achieved by the study of time dependence of $B$-meson decays to the leptons of equal and opposite signs.