We propose that some puzzles in the semileptonic decays of $B$ mesons to the broad ${\overline{D}}^{**}$ states could be clarified by studying at LHCb the corresponding decays with strange mesons $B_s^0\to D_{s0}^{-}$. In particular, we point out that the nonleptonic decay $B_s^0\to D_{s0}^{-}{\pi }^{+}$ and the like, being Class I decays (where factorization is expected to hold), could be a first step in this direction. The interpretation of results in both semileptonic and nonleptonic decays will presumably be easier due to the narrowness of the $D_{s0}^{-}$ state. On the other hand, we make a careful and detailed study of the experimental and theoretical situation in the case of the wide nonstrange ${\overline{D}}^{**}$ case, and we update previous analyses.

• Received 24 October 2012

DOI:https://doi.org/10.1103/PhysRevD.87.054007