Exploring b to s electroweak penguin decays at LHCb
The angular distribution of B → K∗0μ+μ− was studied using 1.0 fb−1 of pp collisions recorded at the LHCb detector at the LHC. Angular observables are measured in five independent bins of the di-muon invariant mass squared, q, and the theoretically interesting region from 1 < q < 6GeV/c4. The results are in good agreement with Standard Model predictions. The contribution from a Kπ S-wave is included in the angular distribution of B → K+π− + −. The Kπ S-wave is shown to have an overall dilution effect on measurements of the B0→ K+π− + − angular observables. For an S-wave contribution of 7% between a Kπ invariant mass squared of 0.64 < p < 1.0GeV/c4, there is a significant bias on the angular observables for dataset of over 500 events. It is possible to remove this bias by incorporating the S-wave into the angular distribution and by fitting the Kπ mass spectrum. The fraction of the S-wave in B → K∗0μ+μ−, FS, was analysed in seven bins of q using 1.0 fb−1 of data from LHCb. The value of FS in the region from 1 < q < 6GeV/c4 and from 0.64 < p < 1.0GeV/c4 was found to be FS = 0.083 +0.057 −0.048(stat.) +0.018 −0.050(syst.). In the regions where no S-wave is found, 95% confidence limits are given. These measurements show that the Kπ S-wave will be a vital consideration for future measurements of B0→ K∗0 + −.