Direct CP violation in KL → π0e+e- beyond leading logarithms

Andrzej J. Buras, Markus E. Lautenbacher, Mikołaj Misiak, Manfred Münz

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86 Scopus citations

Abstract

We analyze the direct CP violation in the rare decay KL → π0e+e- with QCD effects taken into account consistently in the next-to-leading order. We calculate the two-loop mixing between the four-quark ΔS = 1 operators and the operator Q7V = (sd)V - A(ee)V in the NDR and HV renormalization schemes. Using the known two-loop anomalous dimension matrix of the four-quark operators, we find that the coefficient C7V(μ) depends only very weakly on μ, renormalization scheme and ΓMS. The next-to-leading QCD corrections enhance the direct CP violating contribution over its leading order estimate so that it remains dominant in spite of the recent decrease of |Vub/Vcb | and |Vcb|. We expect typically BR(KL → π0e+e-)dir ≈ 6 × 10-12, although values as high as 10-11 are not yet excluded.

Original languageEnglish
Pages (from-to)349-383
Number of pages35
JournalNuclear Physics, Section B
Volume423
Issue number2-3
DOIs
StatePublished - 25 Jul 1994

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