# Search for CP violation in positronium decay.

@article{Yamazaki2010SearchFC,
title={Search for CP violation in positronium decay.},
author={Tomohiro Yamazaki and Toshio Namba and Shoji Asai and Takeshi Kobayashi},
journal={Physical review letters},
year={2010},
volume={104 8},
pages={
083401
}
}
CP violation in the quark sector has been well established over the last decade, but has not been observed in the lepton sector. We search for CP violating decay processes in positronium, using the angular correlation of (S x k{1})(S x k{1}x k{2}), where S is the positronium spin and k{1}, k{2} are the directions of the positronium decay photons. To a sensitivity of 2.2x10{-3}, no CP violation has been found, which is at the level of the CP violation amplitude in the K meson. A 90% confidence…

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