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arXiv · hep-ex/0309075

Observation of the rare decay Ks->pi0e+e-

1 Collaboration
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Abstract

A search for the decay Ks->pi0e+e- has been made by the NA48/1 experiment at the CERN SPS accelerator. Using data collected during 89 days in 2002 with a high-intensity Ks beam, 7 events were found with a background of 0.15 events. The branching fraction BR(Ks->pi0e+e-, m(ee) > 0.165 GeV/c^2) = (3.0^{+1.5}_{-1.2}(stat) +/-0.2 (syst)) x 10^{-9} has been measured. Using a vector matrix element and a form factor equal to one, the measurement gives BR(Ks->pi0e+e-) = (5.8^{+2.9}_{-2.4}) x 10^{-9}.

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1 Collaboration. 2003-09-26. Observation of the rare decay Ks->pi0e+e-. https://doi.org/10.1016/j.physletb.2003.10.001

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