Invariant-mass spectrum of $\Dzero+\overline{\Dzero}$ (left) and $\Dplus$ + D$^-$ (centre) candidates, and invariant-mass difference, $\Delta m = m_{K \pi \pi} - m_{K \pi}$, for $\Dstar$ + D$^{*-}$ candidates (right) in pp collisions at $\sqrts=2.76 $TeV.