We present the first observation of the decay KS → π+π-e+e- based upon the data collected in 1998 by the NA48 experiment at CERN. We have identified a clean sample of 56 events with negligible background contamination. Using KL → π+π-πD/0 decays as normalization sample, the branching ratio is measured to be BR(KS → π+π-e+e-) = [4,5 ± 0.7 (stat) ± 0.4(syst)] × 10-5. This result is in good agreement with the theoretical expectations from the mechanism of inner bremsstrahlung.
|Original language||English (US)|
|Number of pages||8|
|Journal||Physics Letters, Section B: Nuclear, Elementary Particle and High-Energy Physics|
|State||Published - Dec 28 2000|
ASJC Scopus subject areas
- Nuclear and High Energy Physics