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arXiv · 1111.5000

Size of direct CP violation in singly Cabibbo-suppressed D decays

Joachim Brod·Alexander L. Kagan·Jure Zupan
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Abstract

The first experimental evidence for direct CP violation in charm-quark decays has recently been presented by the LHCb collaboration in the difference between the D -> K+ K- and D -> pi+ pi- time-integrated CP asymmetries. We estimate the size of the effects that can be expected within the Standard Model and find that at leading order in 1/mc they are an order of magnitude smaller. However, tree-level annihilation type amplitudes are known to be large experimentally. This implies that certain formally 1/mc-suppressed penguin amplitudes could plausibly account for the LHCb measurement. Simultaneously, the flavor-breaking parts of these amplitudes could explain the large difference between the D -> K+ K- and D -> pi+ pi- decay rates.

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Joachim Brod, Alexander L. Kagan, Jure Zupan. 2015-09-16. Size of direct CP violation in singly Cabibbo-suppressed D decays. https://doi.org/10.1103/physrevd.86.014023

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