PION LOOP CONTRIBUTION TO THE ELECTROMAGNETIC PION CHARGE RADIUS

A phenomenological Dyson-Schwinger equation approach to QCD, formalized in terms of a QCD-based model field theory, is used to calculate the electromagnetic charge radius of the pion. The contributions from the core of dressed quarks and the pion loop are identified and compared. It is shown explicitly that the divergence of the charge radius in the chiral limit is due to the pion loop but that at m(pi) = 0.14 GeV this loop contributes less than 15% to (r(pi)(2)), i.e. the dressed quark core is the dominant determining characteristic for the pion.