Direct measurement of the branching fraction for the decay of D+ - K-e(0)+v(e) and determination of Gamma(D-0 - K(-)e(+)v(e))/Gamma(D+ - K(0)e(+)v(e))

摘要

The absolute branching fraction for the decay D+ --> (K) over bar (0)e(+)nu(e) is determined using 5321 +/- 149 +/- 160 singly tagged D- event sample from the data collected around 3.773 GeV with the BES-II detector at the BEPC collider. In the system recoiling against the singly tagged D- mesons, 34.4 +/- 6.1 events for D+ --> (K) over bar (0)e(+)nu(e) are observed. Those yield the absolute branching fraction to be BF(D+ --> (K) over bar (0)e(+)nu(e)) = (8.95 +/- 1.59 +/- 0.67)%. The ratio of the two partial widths for the decays of D-0 --> (K) over bar (0)e(+)nu(e) and D+ --> (K) over bar (0)e(+)nu(e) is determined to be Gamma(D-0 --> K(-)e(+)nu(e))/Gamma(D+ --> (K) over bar (0)e(+)nu(e)) = 1.08 +/- 0.22 +/- 0.07. (C) 2004 Elsevier B.V. All rights reserved.