The LHCb combined measurements of $\Delta a_{\rm CP} = a_{\rm CP} (D\to K^+K^-)- a_{\rm CP} (D\to \pi^+\pi^-)$ and $a_{\rm CP} (D\to K^+K^-)$ are in tension with predictions employing the Standard Model and U-spin symmetry of QCD. I discuss explanations in terms of new physics and propose test of these explanations in other $D$ decay modes.
Rare charm decays provide unique and complementary insights on flavor and BSM physics. We discuss status and progress in null test searches from theory on decays of charm mesons and baryons into invisibles, photons and leptons and where flavor experiments are currently pushing this frontier. We also discuss CP-violation together with sizable U-spin violation seen in hadronic 2-body decays.
In this talk I review vector-like quarks in leptons in flavour physics and EW precision observables in light of the W mass and the Cabibbo angle anomaly.
We emphasize the analogy between Vector-Like Quarks (VLQ) and Right Handed Neutrinos, illustrating how VLQ lead to naturally supressed FCNC and naturally small violations of 3x3 unitarity in the CKM matrix. VLQ provide a simple solution to the puzzle of eventual lack of unitarity in the first line of the CKM matrix and also provide a framework to have a realistic model with spontaneous CP...
