Acceptance and efficiency corrected angular distribution of the decay products in the rest frame of the \Dstar mesons with respect to the helicity (upper panels) and production (bottom panels) frame. The left panels show the angular distribution for the charm-enhanced \Dstar sample, and the right panel shows the same but for the beauty-enhanced \Dstar sample. The distributions are obtained in $3\pt5~\GeVc$ and are fitted with Eq.~\ref{eq:rzz} to extract the value of spin density matrix element $\rzz^\mathrm{obs}$.