Note on Electron-Neutron Interaction

Assuming a possible short-range interaction between electrons and neutrons of the form $V=K\delta ({\mathrm{r}}_N-{\mathrm{r}}_e)$ where $\delta$ is the Dirac delta function and ${\mathrm{r}}_N$ and ${\mathrm{r}}_e$ are the vector positions of electron and neutron, respectively, it is shown that probably $\mathrm{}\left|K\right|<30m{c}^2{\left(\frac{e^2}{m{c}^2}\right)}^3$ from consideration of the effect of the interaction on slow neutron scattering cross sections. If $K$ is positive and a little less than this upper limit this interaction could be responsible for the observed isotope displacement of spectral energy levels.