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Defi nitive Detection of Orbital Angular Momentum States in Neutrons by Spin-polarized 3He



Terrence J. Jach, John Vinson


A standard method to detect thermal neutrons is the nuclear interaction 3He(n,p)3H. The spin- dependence of this interaction is also the basis of a neutron spin-polarization filter using nuclear polarized 3He. We consider the corresponding interaction for neutrons placed in an intrinsic orbital angular momentum (OAM) state. We derive the relative, polarization-dependent cross-sections for neutrons in an L = 1 OAM state. The absorption of those neutrons results in states J = 0, 1, and 2. Varying the three available polarizations tests that an OAM neutron has been created and probes which states are physically possible. We describe the energetically likely excited states of 4He after absorption, due to the fact that the compound state has odd parity. This provides a de finitive method for detecting neutron OAM states and suggests that intrinsic OAM states offer the possibility to observe new physics, including anomalous cross-sections and new channels of radioactive decay.
Physical Review Letters


neutron, orbital angular momentum, spin polarization, cross section, OAM, Helium-3


Jach, T. and Vinson, J. (2022), Defi nitive Detection of Orbital Angular Momentum States in Neutrons by Spin-polarized 3He, Physical Review Letters, [online],, (Accessed May 18, 2024)


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Created May 11, 2022, Updated December 1, 2022