A first experimental limit on in-matter torsion from neutron spin rotation in liquid 4He

We report the first experimental upper bound to our knowledge on possible in-matter torsion interactions of the neutron from a recent search for parity violation in neutron spin rotation in liquid 4He. Our experiment constrains a coefficient ζ consisting of a linear combination of parameters involving the time components of the torsion fields Tμ and Aμ from the nucleons and electrons in helium which violates parity. We report an upper bound of |ζ|<5.4×10−16 GeV at 68% confidence level and indicate other physical processes that could be analyzed to constrain in-matter torsion.