How large can the SM contribution to CP violation in \( {D_0} - {\overline D_0} \) mixing be?

We reconsider the leading HQE contributions to the absorptive part of the mixing amplitude of neutral D mesons by taking also α s corrections and subleading 1/m c corrections into account. We show that these contributions to Γ12 do not vanish in the exact SU(3) F limit and they also can have a large phase. Moreover, we give an example of a new physics model that can enhance these leading HQE terms to Γ12, which are orders of magnitude lower than the current experimental expectation, by one to two orders of magnitude.