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arXiv · 0909.2486

Precision measurements of rare kaon decays

Evelina Marinova
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Abstract

We report the recent results on rare kaon decays from the NA48/2 experiment. The precise measurement of direct photon emission (DE) in the decay K+- -> pi+- pi0 gamma and its interference (INT), with the INT amplitude being observed for the first time, has been finalized. This study is based on the full NA48/2 data set with about 600k reconstructed K+- -> pi+- pi0 gamma decays which is factor of 30 larger than for previous experiments. Samples of about 7200 reconstructed K+- -> pi+- e+ e-, and more than 3000 K+- -> pi+- mu+ mu- events, with very small background contamination, have been collected. The latter is exceeding the total existing statistics by a factor of five. A precise measurement of the branching fractions and the form factors of the rare decays K+- -> pi+- l+ l- has been performed using different theoretical models. The CP violating asymmetry between K+ and K- in this channel is also measured.

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Evelina Marinova. 2009-09-14. Precision measurements of rare kaon decays. https://arxiv.org/abs/0909.2486

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