A search for the decay K_S --> pi0 e+ 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(K_S --> pi0 e+ e-, m_{ee}>0.165 GeV/c^2)=(3.0+1.5−1.2(stat)±0.2(syst))×10−9 has been measured. Using a vector matrix element and a form factor equal to one, the measurement gives BR(K_S --> pi0 e+ e-)=(5.8+2.9−2.4)×10−9.
Observation of the rare decay K_S --> pi0 e+ e-
BALDINI, Wander;DALPIAZ, Pietro;GIANOLI, Alberto;MARTINI, Mara;PETRUCCI, Ferruccio Carlo;SCARPA, MARCELLA;SAVRIE', Mauro;
2003
Abstract
A search for the decay K_S --> pi0 e+ 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(K_S --> pi0 e+ e-, m_{ee}>0.165 GeV/c^2)=(3.0+1.5−1.2(stat)±0.2(syst))×10−9 has been measured. Using a vector matrix element and a form factor equal to one, the measurement gives BR(K_S --> pi0 e+ e-)=(5.8+2.9−2.4)×10−9.File in questo prodotto:
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