What can we learn from $B^{+}\to D^{(*)-}_{s} K^{+} \pi^{+}$, $B_{d}\to D_{s}^{(*)-} K^{0} \pi^{+}$ and $B_{d}\to D_{s}^{(*)-} K^{*+}$ decays?

Abstract

We study the nonresonant three-body decays of $B^{+}\to D^{(*)-}_{s} K^{+} \pi^{+}$ and $B_{d}\to D_{s}^{(*)-} K^{0} \pi^{+}$. We find that these decays can provide the information on the time-like form factors of $D^{(*)}_{s} K$. We also explicitly investigate $B_{d}\to D_{s}^{(*)-} K^{*+}$ decays by discriminating the nonresonant contributions with the unknown $D^{(*)}_{s}$ wave functions being fixed by the measured mode of $B_{d}\to D_{s}^{-} K^{+}$.