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arXiv · hep-ex/0011093

First Observation of the decay KL -> pi0 e e gamma

The KTeV Collaboration
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Abstract

We report on the first observation of the decay KL -> pi0 ee gamma by the KTeV E799 experiment at Fermilab. Based upon a sample of 48 events with an estimated background of 3.6 +/- 1.1 events, we measure the KL -> pi0 ee gamma branching ratio to be (2.34 +/- 0.35 +/- 0.13)x10^{-8}. Our data agree with recent O(p^6) calculations in chiral perturbation theory that include contributions from vector meson exchange through the parameter a_V. A fit was made to the KL -> pi0 ee gamma data for a_V with the result -0.67 +/- 0.21 +/- 0.12, which is consistent with previous results from KTeV.

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The KTeV Collaboration. 2000-11-28. First Observation of the decay KL -> pi0 e e gamma. https://doi.org/10.1103/physrevlett.87.021801

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