  The angular distribution of the flavor-changing neutral current decay B$^+$
$\to$ K$^+\mu^+\mu^-$ is studied in proton-proton collisions at a
center-of-mass energy of 8 TeV. The analysis is based on data collected with
the CMS detector at the LHC, corresponding to an integrated luminosity of 20.5
fb$^{-1}$. The forward-backward asymmetry $A_{\mathrm{FB}}$ of the dimuon
system and the contribution $F_{\mathrm{H}}$ from the pseudoscalar, scalar, and
tensor amplitudes to the decay width are measured as a function of the dimuon
mass squared. The measurements are consistent with the standard model
expectations.
