  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.
