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arXiv · 1203.6659

A consistent picture for large penguins in D -> pi+ pi-, K+ K-

Joachim Brod·Yuval Grossman·Alexander L. Kagan·Jure Zupan
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Abstract

A long-standing puzzle in charm physics is the large difference between the D0 -> K+ K- and D0 -> pi+ pi- decay rates. Recently, the LHCb and CDF collaborations reported a surprisingly large difference between the direct CP asymmetries, Delta A_CP, in these two modes. We show that the two puzzles are naturally related in the Standard Model via s- and d-quark "penguin contractions". Their sum gives rise to Delta A_CP, while their difference contributes to the two branching ratios with opposite sign. Assuming nominal SU(3) breaking, a U-spin fit to the D0 -> K+ pi-, pi+ K-, pi+ pi-, K+ K- decay rates yields large penguin contractions that naturally explain Delta A_CP. Expectations for the individual CP asymmetries are also discussed.

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Joachim Brod, Yuval Grossman, Alexander L. Kagan, Jure Zupan. 2012-03-29. A consistent picture for large penguins in D -> pi+ pi-, K+ K-. https://doi.org/10.1007/jhep10(2012)161

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