Elastic electron scattering has been used to determine the transverse form factor of the ${}_{}{}^{17}{}_{}{}^{}\mathrm{O}$ ground state in the effective momentum-transfer range $0.55<~q_{\epsilon }<~2.8$ ${\mathrm{fm}}^{-1\mathrm{}}$. The data show considerable deviation from single-particle predictions; in particular, a sizable suppression of the $M3\mathrm{}$ and an enhancement of the high-$q$ side of the $M5\mathrm{}$. Recent shell-model, core-polarization, and meson-exchange calculations are not adequate to explain these effects.

• Received 30 May 1978

DOI:https://doi.org/10.1103/PhysRevLett.42.1444