Neutron interferometry, fifth force and axion like particles

We propose a new possible detection strategy to reveal the fermion–fermion interaction mediated by axions and axion-like particles, based on interferometric measurement of neutron beams. We consider an interferometer in which the neutron beam is split in two sub-beams propagating in regions with differently oriented magnetic fields. The beam paths and the strength of the magnetic fields are set in such a way that the phase difference depends only on the axion-induced interaction. The resulting phase difference is directly related to the presence of axions. Our results show that such a phase might represent, in the future, a tool to probe the existence of axions and axion-like particles or a fifth force with interferometry.