The $a_1$ factorisation coefficient in ${\overline{B}}^0\to D^{(\ast )+}{M}^{-}$ and ${\overline{B}}^0\to D^{(\ast )+}{D}_s^{(\ast )-}$ decays: measurements versus theory

A. Le Yaouanc, J. -P. Leroy, P. Roudeau

Using recent measurements of exclusive B-meson decays we extract the $a_1$ factorization parameter in ${\overline{B}}_d^0\to D^{(\ast {)}^{+}}{K}^{-}/\ddot{I}{€}^{-}$ decay channels. { The values o…