Constraining spacetime nonmetricity with neutron spin rotation in liquid 4He

Abstract

General spacetime nonmetricity coupled to neutrons is studied. In this context, it is shown that certain nonmetricity components can generate a rotation of the neutron's spin. Available data on this effect obtained from slow-neutron propagation in liquid helium are used to constrain isotropic nonmetricity components at the level of 10−22 GeV. These results represent the first limit on the nonmetricity ζ(6)2S000 parameter as well as the first measurement of nonmetricity inside matter.