Implications on the first observation of charm CPV at LHCb

Abstract

Very recently, the LHCb Collaboration observed the $CP$ violation (CPV) in the charm sector for the first time, with $\hat{I}”A_{CP}^{\mathrm{dir}}\equiv A_{CP}(D^0\to K^{+}{K}^{-})-A_{CP}(D^0\to \ddot{I}{€}^{+}\ddot{I}{€}^{-})=(-1.54\pm 0.29)\times 10^{-3}$. This result is consistent with our prediction of $\hat{I}”A_{CP}^{\mathrm{SM}}=(-0.57\sim -1.87)\times 10^{-3}$ obtained in the factorization-assisted topological-amplitude (FAT) approach in [PRD86,036012(2012)]. It implies that the current understanding of the penguin dynamics in charm decays in the Standard Model is reasonable. Motivated by the success of the FAT approach, we further suggest to measure the $D^{+}\to K^{+}{K}^{-}\ddot{I}{€}^{+}$ decay, which is the next potential mode to reveal the CPV of the same order as $10^{-3}$.

10 pages