First Observation of the Rare Decay Mode K-long -> e+ e-

Preprint

1 October 1998

preprint
Published by arXiv in arXiv

https://doi.org/10.48550/arXiv.hep-ex/9810007

Abstract

In an experiment designed to search for and study very rare two-body decay modes of the K-long, we have observed four examples of the decay K-long -> e+ e-, where the expected background is 0.17+-0.10 events. This observation translates into a branching fraction of 8.7^{+5.7}_{-4.1} X 10^{-12}, consistent with recent theoretical predictions. This result represents by far the smallest branching fraction yet measured in particle physics.

Keywords

OBSERVATION TRANSLATES
EXPECTED BACKGROUND
EXPERIMENT DESIGNED
BRANCHING FRACTION
SMALLEST BRANCHING
MODE K LONG
RARE DECAY
DECAY MODE

All Related Versions

Version 1, 1998-10-01, ArXiv
Published version: Physical Review Letters, 81 (20), 4309.

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