A consistent picture for large penguins in D -> pi+ pi-, K+ K-
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.
Keywords
Cite
@article{arxiv.1203.6659,
title = {A consistent picture for large penguins in D -> pi+ pi-, K+ K-},
author = {Joachim Brod and Yuval Grossman and Alexander L. Kagan and Jure Zupan},
journal= {arXiv preprint arXiv:1203.6659},
year = {2015}
}
Comments
24 pages, 8 figures