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arXiv · hep-ex/9902029

Measurement of the Decay KL -> Pi0 Gamma Gamma

A. Alavi-Harati et. al·the KTeV Collaboration
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Abstract

We report on a new measurement of the decay KL -> pi0 gamma gamma by the KTeV experiment at Fermilab. We determine the KL -> pi0 gamma gamma branching ratio to be (1.68 +/- 0.07 +/- 0.08)x10**-6. Our data shows the first evidence for a low-mass gamma gamma signal as predicted by recent O(p**6) chiral perturbation calculations that include vector meson exchange contributions. From our data, we extract a value for the effective vector coupling aV = -0.72 +/- 0.05 +/- 0.06.

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A. Alavi-Harati et. al, the KTeV Collaboration. 1999-02-22. Measurement of the Decay KL -> Pi0 Gamma Gamma. https://doi.org/10.1103/physrevlett.83.917

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