Challenges in Semileptonic B decays

→ Europe/Berlin
02.430 (Mainz Institute for Theoretical Physics<br>Johannes Gutenberg University)

02.430

Mainz Institute for Theoretical Physics<br>Johannes Gutenberg University

Staudingerweg 9 / 2<sup>nd</sup> floor 55128 Mainz
Description
Two of the elements of the Cabibbo-Kobayasha-Maskawa (CKM) quark mixing matrix, Vub and Vcb, are extracted from semi-leptonic B decays. The results of the B factories, analysed in the light of the most recent theoretical calculations, are puzzling. For both |Vcb| and |Vub| the exclusive determination is about 3σ below the inclusive one. This discrepancy has survived several independent checks and could be an indication for New Physics. Fortunately, the upcoming experiment Belle-II has the potential to resolve the issue in the first few years of operation after its start in 2015.

The goal of the proposed workshop is to help developing a medium term strategy of analyses and calculations aimed at the resolution of the puzzle. We plan to have lattice and continuum theorists working together with experimentalists to discuss how to reshape the semi-leptonic analyses in view of the much larger luminosity expected at Belle-II, searching for ways to systematically validate the theoretical predictions in both exclusive and inclusive B decays. We will also discuss the challenges and opportunities theoretical and experimental — of semileptonic Bs, Bc, and Λ b decays, motivated especially be the large samples already available at LHCb.
Dates of Participants
Execetive Summary