The K_S --> gamma gamma decay rate has been measured with the NA48 detector using a high intensity short neutral beam from the CERN SPS. The measured branching ratio BR(K_S --> gamma gamma)=(2.78±0.06stat±0.04syst)×10−6, obtained from 7461±172 K_S --> gamma gamma, is significantly higher than the O(p4) prediction of chiral perturbation theory. Using a KL beam the ratio Gamma(K_L --> gamma gamma)/ Gamma(K_L --> pi0 pi0 pi0) = (2.81 +- 0.01stat +- 0.02syst) has been measured.
Precise measurements of the K_S --> gamma gamma and K_L --> gamma gamma decay rates
CONTALBRIGO, Marco;DALPIAZ, Pietro;GIANOLI, Alberto;MARTINI, Mara;PETRUCCI, Ferruccio Carlo;SAVRIE', Mauro;
2003
Abstract
The K_S --> gamma gamma decay rate has been measured with the NA48 detector using a high intensity short neutral beam from the CERN SPS. The measured branching ratio BR(K_S --> gamma gamma)=(2.78±0.06stat±0.04syst)×10−6, obtained from 7461±172 K_S --> gamma gamma, is significantly higher than the O(p4) prediction of chiral perturbation theory. Using a KL beam the ratio Gamma(K_L --> gamma gamma)/ Gamma(K_L --> pi0 pi0 pi0) = (2.81 +- 0.01stat +- 0.02syst) has been measured.File in questo prodotto:
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