Ludovico Vittorio, "Semileptonic heavy-to-heavy B decays in the Standard Model"

jeudi 1 déc. 2022, 16:00 → 17:00 Europe/Paris

210/1-114 - Salle des Séminaires (IJCLab)

Semileptonic heavy-to-heavy $B$ decays are very intriguing transitions because of the long-standing tension between the inclusive and the exclusive determinations of the Cabibbo-Kobayashi-Maskawa matrix element $|V_{cb}|$. Another discrepancy exists between the Standard Model (SM) expectations and the measurements of the ratios $R(D^{(\ast )})$, which are a test of Lepton Flavour Universality. In both cases, a central role is played by the hadronic Form Factors (FFs) describing these decays. My goal is to review the $b\to c$ quark transitions through the novel Dispersive Matrix approach, which is based on the non-perturbative determination of the dispersive bounds. I will describe how to obtain new values for $|V_{cb}|$ and $R(D^{(\ast )})$ from semileptonic $B\to D^{(\ast )}$ and $B_s\to D_s^{(\ast )}$ decays. Particular attention will be devoted to the semileptonic $B\to D^{\ast }$ channel, which is the main source of the aforementioned tensions. A critical comparison with the results from the Unitarity Triangle Analysis and the ones from HFLAV SM predictions will be then discussed. Finally, I will discuss in detail the state-of-the-art of the computations of the FFs on the lattice and their comparison with experimental measurements.