No Pain, No Gain -- On the Challenges and Promises of Charm Studies

Abstract

The observation of $D^0 - \bar D^0$ oscillations has left us in a tantalizing quandary concerning the theoretical interpretation: are they still compatible with the SM or might they require new dynamics (NP)? A comprehensive search for CP violation in $D$ decays should resolve the issue. Finding it should provide compelling evidence for the intervention of New Physics. While the absolute size of CP asymmetries will presumably be modest at best, the ratio of `signal' to `noise' -- i.e. NP over SM contributions -- might well be larger for $D$ than $B$ transitions. A list of promising channels is provided, most of which should be observable in a hadronic environment. Yet to saturate the discovery potential for NP, we need a Superflavour Factory. Valuable lessons can be obtained by analyzing three- and four-body final states.