First Measurement of $Γ(D^{*+})$

Abstract

We have made the first measurement of the D*+ width using 9/fb of e+e- data collected near the Upsilon(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*+ -> D0 pi+ decay. Our preliminary result is Gamma(D*+) = 96 +- 4 (Statistical) +- 22 (Systematic) keV.