Exploiting the symmetries of P and S wave for B →K^∗μ ⁺μ⁻

© 2015, The Author(s). Abstract: After summarizing the current theoretical status of the four-body decay B → K∗(→ Kπ)μ+μ−, we apply the formalism of spin-symmetries to the full angular distribution, including the S-wave part involving a broad scalar resonance K0∗. While we recover in the P-wave sector the known relation between the angular observables Pi(′), we find in the S-wave sector two new relations connecting the coefficients of the S-wave angular distribution and reducing the number of independent S-wave observables from six to four. Included in the experimental data analysis, these relations can help to reduce the background from S-wave pollution. We further point out the discriminative power of the maximum of the angular observable P2 as a charm-loop insensitive probe of right-handed currents. Moreover, we show that in absence of right-handed currents the angular observables P4′ and P5′ fulfill the relation P4′ = βP5′ at the position where P2 reaches its maximum.