Invariant mass distributions for $\Dzero$ candidates and their charge conjugates with $3< \pt< 4$ GeV/$c$ for $9.5\times10^6$ Pb-Pb collisions in the 30-50% centrality class. The distributions are shown separately for the in-plane (open symbols) and out-of-plane (closed symbols) intervals of azimuthal angle. The curves show the fit functions as described in the text.