Abstract
We present a measurement of the Cabibbo-Kobayashi-Maskawa matrix element , based on of data collected by the Belle detector at the KEKB asymmetric collider. Events are tagged by fully reconstructing one of the mesons, produced in pairs from . The signal for semileptonic decay is distinguished from the background using the hadronic mass , the leptonic invariant mass squared and the variable . The results are obtained for events with , in three kinematic regions (1) , (2) combined with , and by (3) . The matrix element is found to be , where the errors are statistical, systematic including Monte Carlo modeling, theoretical, and from shape function parameter determination, respectively.
- Received 27 May 2005
DOI:https://doi.org/10.1103/PhysRevLett.95.241801
©2005 American Physical Society