@article{Sarenac:2026:10.1103/1mv3-khf8,
author = {Sarenac, D and Lailey, O and Garrad, DV and Vadnere, PR and Shentevski, N and Clark, CW and Cory, DG and Cotter, JP and Ekinci, H and Huber, MG and Paster, JW and Tzeng, Y and Alba, Venero D and Pushin, DA},
doi = {10.1103/1mv3-khf8},
journal = {Physical Review Research},
title = {Experimental limit on neutron orbital angular momentum detection using polarized 2He},
url = {http://dx.doi.org/10.1103/1mv3-khf8},
volume = {8},
year = {2026}
}

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TY  - JOUR
AB  - A recent proposal suggested that neutron orbital angular momentum (OAM) states could be detected via spin-polarized absorption in polarized <sup>3</sup>He, with predicted cross-section variations linked to the neutron’s OAM. We experimentally tested this hypothesis using spin-polarized neutron beams with OAM =-2 to 2, generated by fork-dislocation phase gratings and transmitted through a polarized <sup>3</sup>He cell. Within statistical precision, no OAM-dependent change in the absorption cross section was observed. This null result places stringent constraints on polarized <sup>3</sup>He-based OAM detection schemes. The absence of an effect in the given regime is traced to the proposal’s disregard of the spatial character of neutron OAM: Unlike spin, OAM arises from the transverse phase structure of the wavefunction and couples only through spatial gradients and overlap. The transverse extent of neutron OAM modes expands rapidly, producing a doughnut-shaped intensity profile with negligible overlap with on-axis <sup>3</sup>He nuclei, while off-axis capture samples only a locally uniform phase and reduces the interaction to the known spin dependence. These results establish the limits of absorptive nuclear methods for probing neutron OAM and emphasize the necessity of spatially resolved interactions in any viable detection scheme.
AU  - Sarenac,D
AU  - Lailey,O
AU  - Garrad,DV
AU  - Vadnere,PR
AU  - Shentevski,N
AU  - Clark,CW
AU  - Cory,DG
AU  - Cotter,JP
AU  - Ekinci,H
AU  - Huber,MG
AU  - Paster,JW
AU  - Tzeng,Y
AU  - Alba,Venero D
AU  - Pushin,DA
DO  - 10.1103/1mv3-khf8
PY  - 2026///
SN  - 2643-1564
TI  - Experimental limit on neutron orbital angular momentum detection using polarized 2He
T2  - Physical Review Research
UR  - http://dx.doi.org/10.1103/1mv3-khf8
VL  - 8
ER  - 

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