2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/228543We 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 $Γ_{12}$ 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 $Γ_{12}$, which are orders of magnitude lower than the current experimental expectation, by a factor in the upper double-digit range.4 pages, 3 figuresHigh Energy Physics - Phenomenologytext