We present a new measurement of the branching ratio R of the decay K L→ pi;±e∓ν, denoted as Ke3, relative to all charged KL decays with two tracks, based on data taken with the NA48 detector at the CERN SPS. We measure R=0.4978±0. 0035. From this we derive the Ke3 branching fraction and the weak coupling parameter |Vus| in the CKM matrix. We obtain |Vus|f+(0)=0. 2146±0.0016, where f+(0) is the vector form factor in the Ke3 decay.
|Original language||English (US)|
|Number of pages||11|
|Journal||Physics Letters, Section B: Nuclear, Elementary Particle and High-Energy Physics|
|State||Published - Nov 18 2004|
ASJC Scopus subject areas
- Nuclear and High Energy Physics