Direct CP Violation in B Decays

Abstract

We discuss several aspects of direct CP asymmetries in B decays, which are very useful in spite of hadronic uncertainties in asymmetry calculations. 1) Asymmetries in decays to $D^{(\ast )}{K}^{(\ast )}$, ${\pi }^{+}{\pi }^{-},{\rho }^{+}{\rho }^{-}$, providing precision tests for the CKM phase $\gamma$. 2) Null tests in $B^{+}\to J/\psi K^{+},{\pi }^{+}{\pi }^0$, where a nonzero asymmetry provides evidence for New Physics. 3) Isospin and broken flavor SU(3) relations among CP asymmetries in $B\to K\pi ,\pi \pi$ predicting $A_{CP}(B^0\to K^0{\pi }^0)$ and $A_{CP}(B^0\to {\pi }^0{\pi }^0)$. 4) The significance of $A_{CP}(B^0\to K^{+}{\pi }^{-})\ne A_{CP}(B^{+}\to K^{+}{\pi }^0)$. 5) A potentially stringent constraint on $\gamma$ from $A_{CP}(B^{+}\to K^{+}{\pi }^0)$ and $R_c\equiv 2\Gamma (B^{+}\to K^{+}{\pi }^0)/\Gamma (B^{+}\to K^0{\pi }^{+})$. 6) The role of direct CP asymmetries in $b\to s\bar{q}q$ decays for studying the origin of potential New Physics.

Comments: corrected typo and added references