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arXiv · 1910.14155

A Precision Measurement of the Neutron Scattering Length of He-4 Using Neutron Interferometry

R. Haun·F. E. Wietfeldt·M. Arif·M. G. Huber·T. C. Black·B. Heacock·D. A. Pushin·C. B. Shahi
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Abstract

We report a 0.08 % measurement of the bound neutron scattering length of $^4$He using neutron interferometry. The result is $b = (3.0982 \pm 0.0021 \mbox{ [stat]} \pm 0.0014 \mbox{ [sys]}) \mbox{ fm}$. The corresponding free atomic scattering length is $a = (2.4746 \pm 0.0017 \mbox{ [stat]} \pm 0.0011 \mbox{ [sys]}) \mbox{ fm}$. With this result the world average becomes $b = (3.0993 \pm 0.0025)$ fm, a 2 % downward shift and a reduction in uncertainty by more than a factor of six. Our result is in disagreement with a previous neutron interferometric measurement but is in good agreement with earlier measurements using neutron transmission.

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R. Haun, F. E. Wietfeldt, M. Arif, M. G. Huber, T. C. Black, B. Heacock, D. A. Pushin, C. B. Shahi. 2019-10-30. A Precision Measurement of the Neutron Scattering Length of He-4 Using Neutron Interferometry. https://doi.org/10.1103/physrevlett.124.012501

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