errors. We select candidate events requiring that $\chi^2_b$ is $<$ 12 for the $K\pi$ mode and $<$6 for the $K\pi\pi$.

$B^-\to D^o\omega\pi^-$ Signal
------------------------------

We start with the $D^o\to K^-\pi^+$ decay mode, for events in the $\omega$ peak. We show the candidate $B$ mass distribution, $M_B$, for $\Delta E$ in the side-bands from -7.0 to -3.0$\sigma$ and 7.0 to 3.0$\sigma$ on Fig. \[bm\_omega\_D0\](a). The $\Delta E$ resolution is 18 MeV ($\sigma).$ This gives a good representation of the background in the signal region. We fit this distribution with a shape given as $$\label{eq:background} 
back(r)=p_1 r\sqrt{1-r^2}e^{-p_2(1-r^2)}~~~,$$ where $r=M_B/5.2895$, and the $p_i$ are parameters given by the fit.

We next view the $M_B$ distribution for events having $\Delta E$ within 2$\sigma$ around zero in Fig. \[bm\_omega\_D0\](b). This distribution is fit with a Gaussian signal function of width 2.7 MeV and the background function found above whose normalization is allowed to vary. We find 88$\pm$14 events in the signal peak.

We repeat this procedure for events in the $\omega$ sidebands. We use for our $\chi^2_b$ definition pseudo-$\omega$ masses in the sideband intervals. We show the $M_B$ distribution for events in the $\Delta E$ sideband, defined above, and those having $\Delta E$ within 2$\sigma$ 