Vincenzo Maria Vagnoni (INFN Bologna)
The family of decays mediated by b –> s l^+ l^- transitions provides a rich laboratory to search for effects of physics beyond the Standard Model. In recent years LHCb has found hints of deviations from theoretical predictions both in the rates and angular distributions of such processes. In addition, hints of lepton flavour non-universality have been seen when comparing B^+ –> K^+ mu^+ mu^- and B^+ –> K^+e^+e^-$ decay rates, with the so-called R_K ratio. Similar observables in different decays, such as R_K^* = BR(B^0 –> K^*0 mu^+ mu^-) / BR(B^0 –> K^*0 e^+ e^- and others, can also be measured by LHCb, thus providing further avenues to test the effectiveness of lepton flavour universality. Very recently, a measurement of R_K^* has been reported at an LHCb CERN seminar. Status and prospects of LHCb measurements in this sector will be presented. Furthermore, related measurements involving semitauonic B decays will be also discussed.