New Measurement of the Charge Radius of the Neutron

The neutron transmission through a thorogenic liquid ²⁰⁸Pb sample 2 in. thick has been measured in the neutron energy range between 0.1 and 360 eV at the ORNL neutron source ORELA. Analyzing the shape of the transmission spectra as a function of neutron energy, agreement was found with the predictions by the atomic form factor. With a sensitivity for the mean squared charge radius of the neutron 〈rₙ²〉 as high as 3%, a very reliable and also accurate result of 〈rₙ²〉0ex0ex=0ex0ex-0.113±0.003±0.004fm² was extracted. For the neutron-electron scattering length we obtained ${b}ₙₑ{{0ex}{0ex}}={{0ex}{0ex}}({-}1.31±{}0.03±{}0.04)×{}{10}^{{-}3}{{0ex}{0ex}}fm$.