Search for the decay $\overrightarrow{B}{D}_{s1\mathrm{}}^{+}\mathrm{}\left(2536\right)X$

We have searched for the decay $\overrightarrow{B}{D}_{s1\mathrm{}}^{+}\mathrm{}\left(2536\right)X$ and measured an upper limit for the inclusive branching fraction of $\mathcal{B}\left(\overrightarrow{B}{D}_{s1\mathrm{}}^{+}X\right)<\mathrm{}0.96\%$ at the 90% confidence level. This limit is small compared with the total expected $\overrightarrow{B}{D}^{\left(*\right)}{D}^{\left(*\right)}\mathrm{KX}$ rate. Assuming factorization, the $D_{s1\mathrm{}}^{+}$ decay constant is constrained to be $f_{D_{s1\mathrm{}}^{+}}$<114 MeV at the 90% confidence level, at least 2.5 times smaller than that of $D_s^{+}$.