Systematics of Large Axial Vector Meson Production in Heavy Flavor Weak Decays

Branching ratios observed for $D$ and B decays to final states $a_1(1260)^{\pm} X$ are comparable to those for corresponding decays to $\pi^{\pm} X$ and $\rho^{\pm} X$ and much larger than those for all other decays. Implications are discussed of a "vector-dominance model" in which a $W$ is produced and immediately turns into an axial vector, vector or pseudoscalar meson. Data for decays to all such final states are shown to have large branching ratios and satisfy universality relations. Upper limits on small strong phase differences between amplitudes relevant to CP violation models are obtained from analysis of the predicted and observed suppression of $B^o$ decays into neutral final states $\pi^o X^o$, $\rho^oX^o$ and $a_1^o X^o$. . Branching ratios of $\approx 1%$ are predicted for the as yet unobserved presence of the $D_{s1}(2536)$ charmed-strange axial vector in B decays.