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The unique high-resolution and high-energy features of the electron-scattering facility at the MIT-Bates Accelerator were used to locate a dominant narrow resonance at 15.045 ± 0.035 MeV in 24 Mg. A spin-parity assignment of 6" and an isospin T =1 assignment were made 0 The M6 form factor was measured and compared to the prediction of a theoretical calculation which uses the open-shell random-phase approximation on a shell-model ground state for 24 Mg.Electron scattering experiments in the past, while demonstrating the potential of the electron as a probe of nuclear structure, have been seriously handicapped by inadequate resolution and low intensities. With the new accelerators, this situation has dramatically changed. Thus with a 400-MeV electron beam, we are now able to achieve a 0.015% momentum resolution on a 24 Mg target of thickness ~ 10 mg/cm 2 . With momentum transfers of up to ~ 800 MeV/c, we are able to enhance high-multipolarity magnetic and elec-tric transitions and observe high-spin states in 24 Mg of up to J = 10. In this respect, electron scattering is therefore becoming comparable to heavy-ion transfer reactions which have been used, for example, to demonstrate the existence of narrow high-spin states of excitation energies of 10-20 MeV in 24 Mg with large many-particlemany-hole configuration amplitudes. 1 However, quite unlike the heavy-ion reactions, the inelastic electron scattering cross section is dominated by resonances with a large one-particle-one-00 3 z> o o EXCITATION ENERGY (MeV) FIG. 1. 24 Mg(e 9 e') data taken at 0 = 160 deg and q •• = 2.13 fm" 750

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