The $D^0 - \bar D^0$ mass difference from a dispersion relation
  We study the Standard Model prediction for the mass difference between the two neutral D meson mass eigenstates, $\Delta m$. We derive a dispersion relation based on heavy quark effective theory that relates $\Delta m$ to an integral of the width difference of heavy mesons, $\Delta\Gamma$, over varying values of the heavy meson mass. Modeling the $m_D$-dependence of certain D decay partial widths, we investigate the effects of SU(3) breaking from phase space on the mass difference. We find that $\Delta m$ may be comparable in magnitude to $\Delta\Gamma$ in the Standard Model. 
Adam F. Falk, Yuval Grossman, Zoltan Ligeti, Yosef Nir, Alexey A.   Petrov