Abstract
Using data taken with the CLEO III detector at the Cornell Electron Storage Ring, we have investigated the direct photon spectrum in the decays , , . The latter two of these are first measurements. Our analysis procedures differ from previous ones in the following ways: (a) background estimates (primarily from decays) are based on isospin symmetry rather than a determination of the spectrum, which permits measurement of the and direct photon spectra without explicit corrections for backgrounds from, e.g., states, (b) we estimate the branching fractions with a parametrized functional form (exponential) used for the background, and c) we use the high-statistics sample of to obtain a tagged sample of events, for which there are no QED backgrounds. We determine values for the ratio of the inclusive direct photon decay rate to that of the dominant three-gluon decay to be , , and , where the errors shown are statistical, systematic, and theoretical model dependent, respectively. Given a value of , one can estimate a value for the strong coupling constant from .
16 More- Received 25 December 2005
DOI:https://doi.org/10.1103/PhysRevD.74.012003
©2006 American Physical Society