OBSERVATION OF THE DECAYS DS--]PHI-E-NU-BAR AND D--]K-STAR0E-NU-BAR

Using the ARGUS detector at the e+e- storage ring DORIS II at DESY, we have studied semileptonic charmed meson decays through phi- and K*0 -electron correlations in continuum production. Evidence for the decay D(s-) --> phi-e-nu-BAR has been observed, with a branching ratio relative to the channel D(s-) --> phi-pi- determined to be 0.57 +/- 0.15. The decay D- --> K*0e--nu-BAR was also seen, with a value of 0.55 +/- 0.08 +/- 0.10 extracted for the branching ratio relative to the channel D- --> K+ pi--pi-. The ratio of the two measurements, after application of SU(3) corrections, implies a branching ratio for D(s-) --> phi-pi- of (2.4 +/- 1.0)%.