Hadron Form Factors, Deep-Inelastic Electroproduction, and Massive-Lepton Pair Production: Kinematics or Dynamics?

A theoretical model for the hadrons as extended objects is discussed. The size and shape of hadrons are taken into account by means of an algebraic harmonic-oscillator formalism. This model can explain, with essentially the same parameters, (a) the magnetic form factor of the proton, (b) deep-inelastic electroproduction, and (c) ${\mu }^{+}{\mu }^{-}$ pair production at high energy. The model is also consistent with the known experimental data on the spacelike and timelike pion form factor.