The role of $D^{\star \star }$ in $B^{-}\to D_s^{+}{K}^{-}{\pi }^{-}$

Abstract

The BaBar collaboration has recently reported the observation of the decay mode $B^{-}\to D_s^{+}{K}^{-}{\pi }^{-}$. We investigate the role played by the $D^{\star \star }$ resonances in this decay mode using HQET. Although these resonances cannot appear as physical intermediate states in this reaction, their mass is very close to the $D_s^{+}{K}^{-}$ production threshold and may, therefore, play a prominent role. We pursue this possibility to extract information on the properties of the strong $D^{\star \star }DM$ couplings. As a byproduct of this analysis we point out that future super-$B$ factories may be able to measure the $D_0^0{D}^{\star }\gamma$ radiative coupling through the reaction $B^{-}\to D^{\star }\gamma {\pi }^{-}$.

Comments: Version to appear in Physics Letters B