those in the $\Delta E$ sideband separately.

First we view the plots in the canonical 50 MeV bins. Both background distributions give a consistent if somewhat different estimates of the background shape. (Each background distribution has been normalized to the absolute number of background events as determined by the fit to the $M_B$ distribution.) In any case no prominent narrow structures appear in the histograms for the 10 MeV binning.

The $\overline{B}^o\to D^{*+}\omega\pi^-$ Reaction {#sec:Dspomegapi}
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To investigate the composition of the $(4\pi)^-$ final state, we now investigate the $\pi^+\pi^-\pi^o$ mass spectrum for the events in the $B$ peak. All three $D^o$ decay modes are used. We show the $\pi^+\pi^-\pi^o$ invariant mass distribution for events in the $B$ mass peak in Fig. \[m3pi\_c\_all\] (there are two combinations per event). A clear signal is visible at the $\omega$. The histograms on the figure are for events either in the lower $M_B$ range, from 5.203 GeV to 5.257 GeV, or in the previously defined $\Delta E$ sidebands; no $\omega$ signal is visible.

The purity of the $\omega$ sample can be further improved by restricting candidates to certain regions of the Dalitz plot of the decay products. We define a cut on the 