Branching Fractions and CP-Violating Asymmetries in D => PP Decays

Abstract

We update an $SU(3{)}_F$ analysis of $D\to PP$ decays ($P\equiv \pi ,K$) in which the dominant $SU(3{)}_F$-breaking effects are modeled through final-state interactions. The new fit improves the description relative to the previous parameter set, although significant global tension remains, mainly in charged-$D$ modes. Within the adopted rescattering model, the direct CP asymmetries in $D^0\to {\pi }^{+}{\pi }^{-}$, $K^{+}{K}^{-}$, ${\pi }^0{\pi }^0$, and $K_S^0{K}_S^0$ depend on two additional reduced amplitudes. Using the $D^0\to {\pi }^{+}{\pi }^{-}$ and $D^0\to K^{+}{K}^{-}$ asymmetries as inputs, we derive conditional predictions for the two neutral modes. The OZI-motivated benchmark ${\Delta }_4=0$ is mildly disfavored by the charged-mode asymmetries and leads to substantially smaller asymmetries in the neutral modes, which can be tested with more precise $K_S^0{K}_S^0$ and ${\pi }^0{\pi }^0$ measurements.

arXiv comment13 pages, 1 figure