Flavor physics in lattice QCD as a window into BSM physics: |Vcb| and the B -> D* l nu semileptonic decay

Flavor physics provides a rich variety of phenomena that can be used to probe the SM without requiring the high energies present only in particle accelerators. Among the quantities that could be employed to
perform precision test of the SM, the CKM matrix elements takes up a prominent place. This lecture deals with the |V_{cb}| CKM matrix element, whose determinations through inclusive and exclusive decays
currently display a 2\sigma discrepancy, and show how lattice QCD methods can reduce the uncertainty in the theoretical estimates and rule out (or not) the existence of unknown physics at play.