In this talk I will present a parameterisation of the interference terms between S- and P-wave contributions to the angular distribution of the decay $B\to K^{*}(K\pi)\ell\ell$ that allows us to define new observables. The presence of these extra d.o.f. leads to the identification of new dependence relations among the observables by means of the symmetries of the system. On top of that, we define optimized versions of the new observables in such a way that they exhibit a reduced sensitivity to hadronic uncertainties and we explore their sensitivity to possible contributions of New Physics (NP). Finally, we show experimental prospects of measuring the new observables at LHCb.
Cosimo Nigro, César Jesús-Valls, Jan Ollé