On the recently observed tensions in B decays

In the LHC era, the discovery of New Physics signals is the major ambition of the high-energy physics community and flavor physics can provide access to new heavy particles (Kaluza-Klein modes, supersymmetric particles . . . ) in complementary way with respect to direct searches. Signals of possible deviations with respect to the Standard Model have been recently claimed both by BABAR and LHCb through the analyses of specific semileptonic B-meson decays. First, I’ll focus on semileptonic b → c decay with a τ lepton in the final states for which new BABAR measurements are available, showing a deviation from the Standard Model at 3.4 σ level. I study the effects of a new tensor operator in the effective weak Hamiltonian on a set of observables, in semileptonic B → D(∗) modes as well as in semileptonic B and Bs decays to excited charmed mesons. Moreover, I discuss the phenomenology of the mode B → K∗� +� −, in the framework of a warped extradimensional model. Since a complete set of form factor independent observables have been recently measured by the LHCb Collaboration, with few sizable deviations with respect to the Standard Model in some of them, it would be interesting to put constraints on such a scenario from the FCNC transition b → s�+�−