Pion Electromagnetic Form Factor at Spacelike Momenta

A novel method is employed to compute the pion electromagnetic form factor, F-pi(Q(2)), on the entire domain of spacelike momentum transfer using the Dyson-Schwinger equation (DSE) framework in QCD. The DSE architecture unifies this prediction with that of the pion's valence-quark parton distribution amplitude (PDA). Using this PDA, the leading-order, leading-twist perturbative QCD result for Q(2)F(pi)(Q(2)) underestimates the full computation by just 15% on Q(2) greater than or similar to 8 GeV2, in stark contrast to the result obtained using the asymptotic PDA. The analysis shows that hard contributions to the pion form factor dominate for Q(2) greater than or similar to 8 GeV2, but, even so, the magnitude of Q(2)F(pi)(Q(2)) reflects the scale of dynamical chiral symmetry breaking, a pivotal emergent phenomenon in the standard model.