Lessons from CLEO and FOCUS measurements of D0–D0 mixing parameters

If the true values of the D0–D0 mixing parameters lie within the one sigma ranges of recent measurements, then there is strong evidence for a large width difference, y≳0.01, and large SU(3) breaking effects in strong phases, δ≳π/4. These constraints are model independent, and would become stronger if |M12/Γ12|≪1 in the D0–D0 system. The interesting fact that the FOCUS result cannot be explained by a large mass difference is not trivial and depends on the small D0/D0 production asymmetry in FOCUS and the bounds on CP violating effects from CLEO. The large value of δ might help explain why y∼sin2θc.