First measurement of Γ(D*+) and precision measurement of mD*+-mD0 -: art. no. 032003

We present the first measurement of the D*+ width using 9/fb of e(+) e(-) data collected near the Y(4S) resonance by the CLEO II.V detector. Our method uses advanced tracking techniques and a reconstruction method that takes advantage of the small vertical size of the CESR beam spot to measure the energy release distribution from the D*+ --> D-0 pi(+) decay. We find Gamma(D*+) = 96+/-4 (statistical) +/- 22 (systematic) keV. We also measure the energy release in the decay and compute Deltam = m(D*+) - m(D0) = 145.412+/-0.002 (statistical) +/-0.012 (systematic) MeV/c(2).