Enhanced Charm CP Asymmetries from Final State Interactions

We show that final state interactions (FSI) within a CPT invariant two-channel framework can enhance the charge-parity (CP) violation difference between D^{0}→π^{-}π^{+} and D^{0}→K^{-}K^{+} decays up to the current experimental value. This result relies upon (i) the dominant tree level diagram, (ii) the well-known experimental values for the D^{0}→π^{-}π^{+} and D^{0}→K^{-}K^{+} branching ratios, and (iii) the ππ→ππ and ππ→KK scattering data to extract the strong phase difference and inelasticity. Based on well-grounded theoretical properties, we find the sign and bulk value of the ΔA_{CP} and A_{CP}(D^{0}→π^{-}π^{+}) recently observed by the LHCb Collaboration.