Values of the form factor for the 10.32 MeV transition in ${}_{}{}^{40}{}_{}{}^{}\mathrm{Ca}$ have been measured at six different low momentum transfers corresponding to incident electron energies between 31 and 65 MeV and scattering angles of 127.8° and 162.4°. Analysis of the data shows that the transition is transverse and $M1\mathrm{}$. Our data in conjunction with that of earlier workers yield a value of ${\Gamma }_0\mathrm{}\left(M1\mathrm{}\right)=4.82\mathrm{}\pm 0.26$ eV for the ground state transition width. It is shown that in the low momentum transfer range covered in this work, $q<\mathrm{}0.55\mathrm{}$ ${\mathrm{fm}}^{-1\mathrm{}}$, this result is essentially model independent. Results for the transition at 9.86 MeV state are also discussed.

NUCLEAR REACTIONS ${}_{}{}^{40}{}_{}{}^{}\mathrm{Ca}$($e$,$e^{\prime }$), $E_0=31-65\mathrm{}$ MeV; measured $\frac{d\sigma }{d\Omega }$ at $\theta =127.8\mathrm{}°, 162.4°$; deduced mulipolarity and transition width, ${\Gamma }_0$.

• Received 22 December 1981

DOI:https://doi.org/10.1103/PhysRevC.25.2805