A Determination of the Cabibbo-Kobayashi-Maskawa Parameter | V_(us)| Using K_L Decays

摘要

We present a determination of the Cabibbo-Kobayashi-Maskawa parameter |V_(us)| based on new measurements of the six largest K_L branching fractions and semileptonic form factors by the KTeV (E832) experiment at Fermilab. We find |V_(us)| = 0.2252 +- 0.0008_(KTeV)+- 0.0021_(ext), where the errors are from KTeV measurements and from external sources. We also use the measured branching fractions to determine the CP violation parameter |η_(+-)| = (2.228 +- 0.005_(KTeV) +- 0.009_(ext)) x 10~(-3).