Charge Radii of the Proton and Valence Quarks in the Quasipotential Model

Abstract

The mean square radius of the proton charge distribution was studied in the framework of the relativistic quasipotential quark model in assumption of the SU(6)-symmetry. It was shown that the proton charge radius is represented as function f(m/\gamma)/M^2 for point quarks (m is a quark mass, \gamma is the scale of the coupling energy, M is the nucleon mass, f is undimentional function, which does not depended on M). It was shown, that in the ultra relativistic region the mean square radius of the bound system can have negative value. To describe simultaneously nucleon magnetic moments and proton radius in the oscillator model it is need to suppose that quark has the negative mean square radius <r^2_{1q}> = -1.875/m^2.