Lepton Universality tests in semitauonic $B$ decays at LHCb.

Betti F.
  Martedì 12/09   09:00 - 13:00   Aula A208   I - Fisica nucleare e subnucleare
The observation of a violation of Lepton Universality would be unambiguously a signal of physics beyond the Standard Model. Semileptonic decays of beauty hadrons involving the third-generation leptons are particularly interesting, since a deviation from the Standard Model expectation has been found. The most recent measurement of the observable related to semitauonic $B$ decays, $R(D^{*}) = B(B^{0}\rightarrow D^{*-}\tau^{+}\nu_{\tau})/B(B^{0}\rightarrow D^{*-}\mu^{+}\nu_{\mu})$, using the hadronic $\tau$ decay channel, performed by LHCb with data collected during Run 1 will be presented. The prospective measurements for other observables related to $b\rightarrow c\tau\nu$ transition, as $R(D^+), R(J/\psi)$ and $R(\Lambda_{c})$, will also be reported.