A proposed search for new light bosons using a table-top neutron Ramsey   apparatus
  If a new light boson existed, it would mediate a new force between ordinary fermions, like neutrons. In general such a new force is described by the Compton wavelength $\lambda_c$ of the associated boson and a set of dimensionless coupling constants. For light boson masses of about $10^-4$ eV, $\lambda_c$ is of the order millimeters. Here, we propose a table-top particle physics experiment which provides the possibility to set limits on the strength of the coupling constants of light bosons with spin-velocity coupling. It utilises Ramsey's technique of separated oscillating fields to measure the pseudo-magnetic effect on neutron spins passing by a massive sample. 
F. M. Piegsa, G. Pignol
nucl-ex physics.ins-det