we observed in $\overline{B}\to D^{*}\omega\pi^-$ decays.

Angular Distributions in $D\omega\pi^-$ {#sec:Dangular}
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We can determine the spin and parity of the $A^-$ particle by studying the angular distributions characterizing its decay products. The decay chain that we are considering is $B\rightarrow A\ D$; $A\rightarrow
\omega \pi$ and $\omega \rightarrow \pi ^+ \pi ^- \pi ^o$. The helicity formalism [@helicity] is generally used in the analysis of these sequential decays. This formalism is well suited to relativistic problems involving particles with spin $\vec{S}$ and momentum $\vec{p}$ because the helicity operator $h=\vec{S}\cdot \vec{p}$ is invariant under both rotations and boosts along $\hat{p}$.

=3.5in

There are two relevant reference frames. The first one, that we will define $x_Ay_Az_A$ is the rest frame of the $A$ particle, with the $\hat{z_A}$ axis pointing in the $A$ direction of motion in the $B$ rest frame. The second one, $x_{\omega}y_{\omega}z_{\omega}$, is related to $x_Ay_Az_A$ by the rotation through 3 Euler angles $\phi _A,\theta _A,-\phi _A$, as shown in Fig. \[eul-angles\]. The angle $\phi _A$ defines the orientation of the plane containing the $\omega$ direction in the A rest frame and the $\hat{z_A}$ axis with respect to the $\hat{x_A}-\hat{z_A}$ plane. The $\hat{x_A}$ direction is arbitrary. The angles $\theta 