Lessons from BaBar and Belle measurements of D-Dbar mixing parameters

Abstract

The BaBar and Belle experiments have recently presented evidence for D-Dbar mixing. We explain the following points: (i) The measurements imply width difference $y \sim 0.01$. In the limit of small CP violation, the CP-odd state is longer-lived; (ii) $y\sim0.01$ is consistent with the Standard Model. It suggests that SU(3) breaking from phase space effects is likely to play a major role; (iii) There is no evidence for either large mass splitting or CP violation. Consequently, there is no hint for new physics; (iv) The stronger bounds on the mass splitting and on CP violation imply that, if squarks are observed at the LHC, it is unlikely that they will be non-degenerate.