2019/20 Lessons from $\tau ({\Omega }_c^0)$ \& $\tau ({\Xi }_c^0)$ and {\bf CP} asymmetry in charm decays

Abstract

Our 2003 "Cicerone" had discussed charm dynamics with different directions and levels \cite{CICERONE}. Here we focus on two items, where the `landscape' has changed sizably. (A) The lifetimes \& semi-leptonic decays of charm hadrons show the impact of non-perturbative QCD and to which degree one can apply Heavy Quark Expansion (HQE) for charm hadrons. It is more complex as we have learnt from 2019/20 data. (B) {\bf CP} asymmetry has been established in 2019 \cite{LHCbGuy}: $\Delta A_{\mathbf{CP}}\equiv A_{\mathbf{CP}}(D^0\to K^{+}{K}^{-})-A_{\mathbf{CP}}(D^0\to {\pi }^{+}{\pi }^{-})$=$-(1.54\pm 0.29)\cdot 10^{-3}$ is quite an achievement by the LHCb collaboration! Our community is at the beginning of a long travel for fundamental dynamics. Can the SM account for these? We discuss the assumptions that were made up to 2018 data and new conclusions from 2019/20 ones. We need more data; however, one has to discuss correlations between different transitions. We give an {\bf Appendix} what we have learnt for large {\bf CP} asymmetry in $K_L\to {\pi }^{+}{\pi }^{-}{e}^{+}{e}^{-}$.

Comments: 30 pages, 4 figures