Lessons from CLEO and FOCUS measurements of D0-(D0)over-bar mixing parameters

If the true values of the D degrees-<(D degrees)over bar> mixing parameters lie within the one sigma ranges of recent measurements, then there is strong evidence for a large width difference, y greater than or similar to 0.01, and large SU(3) breaking effects in strong phases, delta greater than or similar to pi/4. These constraints are model independent, and would become stronger if /M-12/Gamma(12)/ much less than 1 in the D degrees-<(D degrees)over bar> system. The interesting fact that the FOCUS result cannot be explained by a large mass difference is not trivial and depends on the small D degrees/<(D degrees)over bar> production asymmetry in FOCUS and the bounds on CP violating effects from CLEO, The large value of delta might help explain why y similar to sin(2)theta(c). (C) 2000 Elsevier Science B.V. All rights reserved.