D 0 − D ¯ 0 mixing in the Dyson-Schwinger approach

In view of difficulty to reproduce observables in the D 0 − D ¯ 0 mixing via the operator product expansion, we discuss the Dyson-Schwinger approach to this process. Formulated by the parametrization of quark propagators, SU(3) breaking relevant to charm mixing is evaluated in such a way that properly takes account of dynamical chiral symmetry breaking. The D ¯ 0 → D 0 transition is discussed in the vacuum-insertion approximation with locality of the light valence-quark field, represented by the decay constant of D 0 meson as well as relevant momentum integrals. It is found that dimensionless mass-difference observable in this approach leads to | x | = ( 1.3 – 2.9 ) × 10 − 3 , the order of magnitude comparable to the HFLAV data, and thereby offering a certain improvement as a theoretical framework.