Asymptotic behavior of the pion electromagnetic form factors in Bethe-Salpeter model

Abstract

Asymptotic behavior of the pion form factors has been discussed treating pion as a bound state of the elementary nucleon and antinucleon system. The matrix-element of the electromagnetic current is written in terms of the Bethe-Salpeter amplitude for the nucleon-antinucleon bound system. Using suitable approximations the Bethe-Salpeter equation for nucleon-antinucleon bound state with nucleons as Dirac spinors has been solved and the corresponding off-shell pion form factors are determined. The form factors are strongly interaction dependent. For coupling g²/16π² = 15/4 the form factors vanish asymptotically like t^-1 and for 14/4 < g²/16π² < 15/4 the form factors still vanish but less rapidly than t^-1.