# Figure 1

 Invariant-mass (mass-difference) distributions of $\Dzero$, $\Dplus$, ($\Dstar$) and $\Ds$candidates and charge conjugates in three $\pt$ intervals for a sample of pp collisions at $\sqrt s=7~\tev$with $L_{\rm int}=6.0~{\rm nb}^{-1}$. The curves show the fit functions as described in the text The contribution of reflections for the $\Dzero$ meson is included The values of mean ($\mu$) and width ($\sigma$) of the signal peak arereported together with the signal counts ($S$) in the mass interval ($\mu$- 3$\sigma,\mu + 3\sigma$).