Neutron Polarimetric Imaging in Searches for Exotic Spin-Dependent Neutron Interactions with Matter*

Neutron spin rotation is a sensitive method to search for exotic spin-dependent neutron interactions with matter, as shown in our upper bounds on exotic parity-odd neutron interactions in matter^[1] and exotic neutron spin-orbit interactions^[2] using neutron polarimetry. We discuss the evolution of this approach to include neutron imaging through its application to an ongoing series of measurements^[3] to search for exotic polarized neutron/polarized electron interactions in polycrystalline terbium iron garnet. Tb₃Fe₅O₁₂ is a ferrimagnetic material with a net electron polarization and a zero internal magnetization at its compensation temperature Tc. The NSR-Ferrimagnets Collaboration has utilized the HFIR CG-1D MARS imaging beamline to search for neutron spin rotation from our ferrimagnetic sample at T_c. We will describe the neutron polarimetry, neutron imaging detection, sample thermometry, magnetometry, and cryogenics.

[1] H. Yan, and W. M. Snow, Phys. Rev. Lett. 110, 082003 (2013)

[2] C. Haddock et al., Phys. Lett. B 783, 227 (2018)

[3] Mulkey, T. (2024, June 27). Spin-dependent fifth force and compensated ferrimagnetism measurements in terbium iron garnets. (ACNS 2024 Conference, Knoxville, TN, United States)