Measurement of the D^{*}(2010)^{+} Meson Width and the D^{*}(2010)^{+}-D^{0} Mass Difference

We measure the mass difference Δm0 between the D^*(2010)^+ and the D^0 and the natural linewidth Γ of the transition D^*(2010)^+→D^0π^+. The data were recorded with the BABAR detector at center-of-mass energies at and near the Υ(4S) resonance, and correspond to an integrated luminosity of approximately 477  fb^(-1). The D0 is reconstructed in the decay modes D^0→K^-π^+ and D^0→K^-π^+π^-π^+. For the decay mode D^0→K^-π^+ we obtain Γ=(83.4±1.7±1.5)  keV and Δm_0=(145425.6±0.6±1.8)  keV, where the quoted errors are statistical and systematic, respectively. For the D^0→K^-π^+π^-π^+ mode we obtain Γ=(83.2±1.5±2.6)  keV and Δm_0=(145426.6±0.5±2.0)  keV. The combined measurements yield Γ=(83.3±1.2±1.4)  keV and Δm_0=(145425.9±0.4±1.7)  keV; the width is a factor of approximately 12 times more precise than the previous value, while the mass difference is a factor of approximately 6 times more precise.