We present a study of D° mixing using events of the type D* + -* K + D°y with D°-+K + K~ and D°-» K + K~7t + 7t~. The decay time is used to separate mixing from doubly Cabibbo-suppressed decays. We observe no evidence for mixing in either mode. Combining the results from the two decay modes, we find r M =0.0005 ± 0.0020 or r M < 0.0037 at the 90% confidence level, where r M is the ratio of wrongsign decays from mixing to right-sign decays. We also present limits on doubly Cabibbo-suppressed decays and consider the effect of possible interference.

Using the Tagged Photon Spectrometer and a high-energy photon beam, we have searched for excited states of charm in Fermilab experiment E691. We have found evidence for a state of mass 2459 ± 3 (stat.) ±2 (syst.) MeV/c 2 and width 20 ± 10 ± 5 MeV/c 2 which decays to D + 7t~. The fraction of D + coming from Z)**°(2459) is 0.07 ± 0.02 ± 0.02. We also confirm the Z)**°(2420)-+ D* + K~ decay observed previously in e + e ~ experiments and present evidence for its charged counterpart. PACS numbers: 14.40.Jz, 13.25.+m While the S-wave charmed mesons, the D, Z)*(2010),