Null-plane phenomenology for the pion decay constant and radius

The pion decay constant and the electromagnetic form factor are computed by using quark diagrams and projecting the bound-state wave function on the null plane. We show that the resulting formulas are the same as those of the Hamiltonian front-form scheme. The connection between the radius (r_π) and the pion decay constant (f_π) is studied using different models of confinement.