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A First Experimental Limit on In-matter Torsion from Neutron Spin Rotation in Liquid He-4

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 He-4. Our experiment constrains a coefficient $ζ$ consisting of a linear combination of parameters involving the time components of the torsion fields $T^μ$ and $A^μ$ from the nucleons and electrons in helium which violates parity. We report an upper bound of $|ζ|<9.1x10^{-23}$ GeV at 68% confidence level and indicate other physical processes that could be analyzed to constrain in-matter torsion.