Size of direct CP violation in singly Cabibbo-suppressed D decays
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.
Keywords
Cite
@article{arxiv.1111.5000,
title = {Size of direct CP violation in singly Cabibbo-suppressed D decays},
author = {Joachim Brod and Alexander L. Kagan and Jure Zupan},
journal= {arXiv preprint arXiv:1111.5000},
year = {2015}
}
Comments
5 pages, 2 figures. Corrected numerical error; our estimated range for Delta A_CP is reduced by a factor of two