Angular analysis of charged and neutral B → Kµ+µ- decays

Abstract

The angular distributions of the rare decays B → K+µ+µ- and B0 → K0aSμ+μ- are studied with data corresponding to 3 fb-1 of integrated luminosity, collected in proton-proton collisions at 7 and 8TeV centre-of-mass energies with the LHCb detector. The angular distribution is described by two parameters, FH and the forward-backward asymmetry of the dimuon system AFB, which are determined in bins of the dimuon mass squared. The parameter FH is a measure of the contribution from (pseudo)scalar and tensor amplitudes to the decay width. The measurements of AFB and FH reported here are the most precise to date and are compatible with predictions from the Standard Model.