Direct CP violation in two-body hadronic charmed meson decays
Journal
Physical Review
Journal Volume
D85
Pages
034036
Date Issued
2012-01
Author(s)
Chiang, Cheng-Wei
Abstract
Motivated by the recent observation of CP violation in the charm sector by LHCb, we study direct CP asymmetries in the standard model (SM) for the singly Cabibbo-suppressed two-body hadronic decays of charmed mesons using the topological-diagram approach. In this approach, the magnitude and the phase of topological weak annihilation amplitudes, which arise mainly from final-state rescattering, can be extracted from the data. Consequently, direct CP asymmetry adir(tree) at tree level can be reliably estimated. In general, it lies in the range 10 -4 < adir(tree) < 10 -3. Short-distance QCD penguins and penguin annihilation are calculated using QCD factorization. Their effects are generally small, especially for D→VP modes. Since weak penguin annihilation receives long-distance contributions from the color-allowed tree amplitude followed by final-state rescattering, it is expected to give the dominant contribution to the direct CP violation in the decays D0→K +K - and D0→π +π-, in which adir(tree) is absent. The maximal ΔaCPdir, the direct CP asymmetry difference between the above-mentioned two modes, allowed in the SM is around -0.25%, more than 2σ away from the current world average of -(0.645±0.180)%. © 2012 American Physical Society.
Type
journal article