High-Energy Muon-Proton Scattering: Muon-Electron Universality

Measurements of the $\mu -p$ elastic cross section in the range $0.15<\mathrm{}{q}^2<0.85\mathrm{}$ ${(\mathrm{G}\mathrm{e}\mathrm{V}/\mathit{c})}^2$ are compared with similar $e-p$ data. We find an apparent disagreement between the muon and electron experiments which can possibly be accounted for by a combination of systematic normalization errors.