6533b7d5fe1ef96bd126460d

RESEARCH PRODUCT

ε′/ε in the standard model

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We overview the detailed analysis of e ' /e within the Standard Model, pre- sented in ref. (1). When all sources of large logarithms are considered, both at short and long distances, it is possible to perform a reliable Standard Model estimate of e ' /e. The strong S-wave rescattering of the final pions has an important impact on this observ- able (1, 2). The Standard Model prediction is found to be (1) Re(e ' /e) = (1.7 ±0.9) � 10 −3 , in good agreement with the most recent experimental measurements. A better estimate of the strange quark mass would reduce the uncertainty to about 30%.