Measurement of angular parameters from the decay B⁰  → K$^{⁎0}$ μ⁺ μ⁻ in proton–proton collisions at √s 8 TeV

Angular distributions of the decay B⁰  → K$^{⁎0}$ μ⁺ μ⁻ are studied using a sample of proton–proton collisions at
√s=8TeV collected with the CMS detector at the LHC, corresponding to an integrated luminosity of
20.5fb⁻¹ . An angular analysis is performed to determine the P₁ and P$^{'}$₅ parameters, where the P$^{'}$₅ parameter is of particular interest because of recent measurements that indicate a potential discrepancy with the standard model predictions. Based on a sample of 1397 signal events, the P₁ and P$^{'}$₅ parameters are determined as a function of the dimuon invariant mass squared. The measurements are in agreement with predictions based on the standard model.