Axion like particles, fifth force and neutron interferometry

We report on recent result according to which the fermion-fermion interaction mediated by axions and axion-like particles can be revealed by means of neutron interferometry. We assume that the initial neutron beam is split in two beams which are affected by differently oriented magnetic fields, in order that the phase difference depends only by the axion-induced interaction. In this way, the phase difference is directly related to the presence of axions.