Electromagnetic Polarizabilities and Charge Radii of the Nucleons in the Diquark-model

Abstract

The diquark model is used to calculate the electromagnetic polarizabilities and charge radii of the nucleons for three different potentials. Making the scalar diquark lower in mass introduces a mixing angle $\theta$ between the $|56⟩$ and $|70⟩$ states ,which allows an improvement in value of all 6 properties. Generalizing the Gamov-Teller matrix and the magnetic moment operator to the diquark model gives constraints on this mixing. We obtain for the Richardson potential $\theta =23.2^{\circ },$ ${\overline{\alpha }}_p=7.9_{-0.9}^{+1.0}\times 10^{-4}f{m}^3,$ ${\overline{\alpha }}_n=7.7_{-0.6}^{+0.3}\times 10^{-4}f{m}^3,$ ${\overline{\beta }}_p=5.4_{-0.4}^{+1.6}\times 10^{-4}f{m}^3,$ $\overline{\beta }$ ${⟨r^2⟩}_p=0.37_{-0.03}^{+0.02}f{m}^2,$ ${⟨r^2⟩}_n=-0.07_{-0.02}^{+0.03}f{m}^2.$ Additional pion cloud contributions could improve on all six results.

Comments: 15 Pages, Latex, Figs on request, to be published Phys.Lett.B. Minor errors corrected and eqn 5,6,8,9 corrected