First Observation of the Rare Decay Mode $K_{L}^{0} \to e^{+} e^{-}$

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16 November 1998

journal article
research article
Published by American Physical Society (APS) in Physical Review Letters

Vol. 81 (20) , 4309-4312
https://doi.org/10.1103/physrevlett.81.4309

Abstract

In an experiment designed to search for and study very rare two-body decay modes of the

K_{L}^{0}

, we have observed four examples of the decay

K_{L}^{0} \to e^{+} e^{-}

, where the expected background is

0.17 \pm 0.10

events. This observation translates into a branching fraction of

{8.7}_{- 4.1}^{+ 5.7} \times 10^{- 12}

, consistent with recent theoretical predictions. This result represents by far the smallest branching fraction yet measured in particle physics.

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Version 1, 1998-10-01, ArXiv

This publication has 18 references indexed in Scilit:

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