Comments to the problem of experimental determination of the neutron-electron scattering length and its theoretical interpretation

Abstract

We discuss the experimental data on the n,e-scattering length bne and the values of mean square charge radius of the neutron <r^2> obtained from them. It is shown that the accumulated during the last 50 years most significant experimental estimates of the bne are not contradictory and lead to the average value <r^2>=-0.1178+-0.0037 fm^2. Assuming that all the authors have underestimated the errors of their measurements by a factor of 1.7, the combined fit of all available experimental data would lead to Chi^2~1 per degree of freedom. Different modern theoretical predictions of <r^2> are considered. They are found to be in a good agreement with the obtained experimental value <r^2>. However the existing theoretical description of the structure of neutron does not provide a value of <r^2> with a sufficient accuracy.