Measurement of the decay fractions of D* mesons

Using the ARGUS detector at the DORIS II electron-positron storage ring at DESY, we have measured BR(D*+ → D0π+) = (68.8 ± 2.4 ± 1.3)%, BR(D*+ → D+π0) = (31.2 ± 1.1 ± 0.8)%, BR(D*+ → D+γ) < 5.2% (90%CL), BR(D*0 → D0π0) = (59.6 ± 3.5 ± 2.8)%, and BR(D*0 → D0γ) = (40.4 ± 3.5 ± 2.8)%, and the mass difference Δm0 = m(D*0) - m(D0) = (142.2 ± 0.3 ± 0.2) MeV/c2. (orig.)