Measurement of the D*(2010)+ natural line width and the D*(2010)+ - D0 mass difference

We measure the mass difference, \Delta m_0, between the D*(2010)+ and the D0 and the natural line width, \Gamma, of the transition D*(2010)+ -> D0 pi+. The data were recorded with the BABAR detector at center-of-mass energies at and near the Upsilon(4S) resonance, and correspond to an integrated luminosity of approximately 477 1/fb. The D0 is reconstructed in the decay modes D0 -> K- pi+ and D0 -> K- pi+ pi- pi+. For the decay mode D0 -> K- pi+ we obtain Gamma = (83.4 +- 1.7 +- 1.5) keV and \Delta m_0 = (145 425.6 +- 0.6 +- 1.8) keV, where the quoted errors are statistical and systematic, respectively. For the D0 -> K- pi+ pi- pi+ mode we obtain \Gamma = (83.2 +- 1.5 +- 2.6) keV and \Delta m_0 = (145 426.6 +- 0.5 +- 2.0) keV. The combined measurements yield \Gamma = (83.3 +- 1.2 +- 1.4) keV and \Delta m_0 = (145 425.9 +- 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.