Form Factors for StrongM1Transitions in Light Nuclei

Strong peaks corresponding to magnetic-dipole excitation of the nucleus were observed in the energy spectrum of electrons scattered at 180° from targets of ${\mathrm{Li}}^6$, C, Mg, and Si. The momentum transfer dependence of the excitation of these peaks was investigated by using primary electrons of 40, 55, and 70 MeV. From the measured cross sections and the Born approximation theory the inelastic form factors can be obtained. The radiative transition probability from the excited state to the ground state gives the first point on the curve of form factor as a function of momentum transfer. In the case of ${\mathrm{C}}^{12}$ a shell-model theory of the magnetic-dipole transition gives a form-factor curve in fair agreement with the experimental results.