Precision Measurement of the Neutron-Electron Scattering Length

An update on the effort to measure the neutron-electron scattering length at the 0.5% level will be provided.  The experiment probes the Q²-dependence of pendellösung interference in silicon and germanium.  The pendellösung phase shift for three different Bragg conditions per material at a fixed temperature allows for the separation of neutron-electron scattering from the Debye-Waller factor.  The data may also be used to place competitive limits on the strength of an angstrom-scale fifth force.