Figure 1

Invariant mass distributions of $\Dzero$ candidates and charge conjugates in four selected $\pt$ intervals considered for the analysis. The topological and kinematical selections applied to obtain these distributions are described in the paper. The fit functions showed in the figure consist of a sum of a Gaussian and an exponential to describe the signal and the background respectively. The values of the signal (S) and background counts (B) integrated in $\pm 3 \sigma$ region around the centroid of the Gaussian are reported.