Elastic electromagnetic form factors ofLi6from three-body models

Within the context of three-body (alpha particle plus two nucleons) models of ${}_{}{}^6{}_{}{}^{}\mathrm{Li}$, the ground-state longitudinal (C0,C2) and transverse (M1) electromagnetic form factors of the ${}_{}{}^6{}_{}{}^{}\mathrm{Li}$ nucleus are calculated. In the zero-momentum-transfer limit of the C0 and M1 form factors, the charge radius and the magnetic moment of ${}_{}{}^6{}_{}{}^{}\mathrm{Li}$ are extracted, respectively. An attempt is made to extract the ${}_{}{}^6{}_{}{}^{}\mathrm{Li}$ electric-quadrupole moment from the threshold behavior of the C2 form factor. By projecting the alpha-deuteron component from the three-body wave function, the contribution and role of this part of the wave function is ascertained for the elastic form factors. The Pauli exclusion principle between the alpha particle and either nucleon is found to be responsible for the minima in the form factors. With the exception of the quadrupole (only for high q values) form factor, the particular representation of the Pauli repulsion between the alpha-particle and nucleon in the $S_{1/2}$ partial wave of the interaction is unimportant. The presence of the nucleon-nucleon tensor force suppresses the values of the form factors at high q.