Standard model predictions and new physics sensitivity in B → D D decays
An extensive model-independent analysis of $B\ensuremath{\rightarrow}DD$ decays is carried out employing $SU(3)$ flavor symmetry, including symmetry-breaking corrections. Several theoretically clean observables are identified which allow for testing the standard model. These include the known time-dependent $CP$ asymmetries, the penguin pollution of which can be controlled in this framework, but notably also quasi-isospin relations which are experimentally well accessible and unaffected by symmetry-breaking corrections. Theoretical assumptions can be kept to a minimum and controlled by additional sum rules. Available data are used in global fits to predict the branching ratio for the ${B}^{0}\ensuremath{\rightarrow}{D}_{s}^{+}{D}_{s}^{\ensuremath{-}}$ decay as well as several $CP$ asymmetries which have not been measured so far, and future prospects are analyzed.