A search for possible long range spin dependent interactions of the neutron from exotic vector boson exchange

Abstract We present a search for possible spin dependent interactions of the neutron with matter through exchange of spin 1 bosons with axial vector couplings as envisioned in possible extensions of the Standard Model. This was sought using a slow neutron polarimeterthat passed transversely polarized slow neutrons by unpolarized slabs of material arranged so that interactions would tilt the plane of polarization and develop a component along the neutron momentum. The result for the rotation angle, ϕ ′ = [ 2.8 ± 4.6 ( s t a t . ) ± 4.0 ( s y s . ) ] × 10 − 5 rad/m is consistent with zero. This result improves the upper bounds on the neutron-matter coupling g A 2 by about three orders of magnitude for force ranges in the mm– μm regime.