Charm CP: $\Delta A_{CP}$ and Radiative decays

Abstract

Motivated by the very important discovery of CP violation in charm-decays for the first time, by the LHCb collaboration, the role of nearby resonances such as the scalar $f_0(1710)$ in accounting for the observed CP is discussed. It is suggested that the influence of such a resonance may also explain the long-standing puzzle of such a large breaking of SU(3) seen in its decays. It is also explained that intervention of such resonance(s) will render first principles calculations of $\Delta A_{CP}$ rather difficult. Instead, it is proposed that searches for CP violation in simple radiative final states, such as $D^0 \to \gamma \phi [\to K^+ K^-]$, $D^0 \to l^+ l^- \pi$ etc. has much better chance of theoretical precision studies and therefore theoretical and experimental investigations therein are strongly urged.