Pion Helicity Structure And Its Consequence For The Hard Scattering Form Factor

In a study of the elastic pion form factor for large momentum transfers based on a modified perturbative QCD (PQCD) approach we have included helicity components that are customarily neglected. Along with the inclusion of transverse momentum, this gives a large suppression of the form factor from the prediction of the original hard scattering model based on PQCD in the $Q^{2}$ domain where experimental data are available. We conclude that nonperturbative contributions will dominate in this region.