Nonperturbative relativistic approach to pion form factor: predictions for future JLab experiments

Abstract

Some predictions concerning possible results of the future JLab experiments on the pion form factor F_pi(Q^2) are made. The calculations exploit the method proposed previously by the authors and based on the instant-form Poincare invariant approach to pion considered as a quark-antiquark system. Long ago, this model has predicted with surprising accuracy the values of F_pi(Q^2) measured later in JLab experiment. The results are almost independent from the form of wave function. The pion mean square radius <r^2_pi> and the decay constant f_pi also agree with experimental values. The model gives power-like asymptotic behavior of F_pi(Q^2) at high momentum transfer in agreement with QCD predictions.