We compute the hadronic matrix elements of the complete set of local four-quark operators relevant for neutral B-meson mixing in the Standard Model and beyond as well as for the the shortdistance contributions to D 0 mixing. In addition we calculate the leptonic decay constants for the Band D-meson systems on the same sets of gauge-field ensembles. Both mixing matrix elements and decay constants are computed with asqtad-improved light quarks and clover heavy quarks in the Fermilab

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... . We use the MILC three-flavor asqtad ensembles at four lattice spacings between appoximately 0.11 fm and 0.043 fm. We present nearly final values for the mixing matrix elements, and find for the SU(3) breaking ratio ξ = 1.203(17)(6) sea c . The second error accounts for the omission of charm quarks in the sea while the first error includes all other sources of uncertainty. Our result for ξ when combined with the experimentally measured frequencies gives |V td | |V ts | = 0.2047(4) exp (29) th (10) sea c . Finally, we report on our progress towards finalizing our decay constant and bag parameter analyses.