Precision Measurement of the Neutron Scattering Length of $^{4}\mathrm{He}$ Using Neutron Interferometry

Precision Measurement of the Neutron Scattering Length of ${}^{4}{He}$ Using Neutron Interferometry

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

Phys. Rev. Lett. 124, 012501 – Published 7 January 2020

Abstract

We report a 0.08% measurement of the bound neutron scattering length of ${}^{4}{He}$ using neutron interferometry. The result is $b = (3.0982 \pm 0.0021 [stat] \pm 0.0014 [syst]) fm$ . The corresponding free atomic scattering length is $a = (2.4746 \pm 0.0017 [stat] \pm 0.0011 [syst]) fm$ . 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.

Received 30 October 2019

DOI:https://doi.org/10.1103/PhysRevLett.124.012501

Physics Subject Headings (PhySH)

Few-body systems Neutron physics

Nuclear PhysicsCondensed Matter, Materials & Applied Physics

Authors & Affiliations

R. Haun and F. E. Wietfeldt

Department of Physics and Engineering Physics, Tulane University, New Orleans, Louisiana 70118, USA

M. Arif^* and M. G. Huber

National Institute of Standards and Technology, Gaithersburg, Maryland 20899, USA

T. C. Black

Department of Physics, University of North Carolina-Wilmington, Wilmington, North Carolina 28403, USA

B. Heacock

Department of Physics, North Carolina State University, Raleigh, North Carolina 27695, USA and Triangle Universities Nuclear Laboratory, Durham, North Carolina 27708, USA

D. A. Pushin

Department of Physics and Astronomy, University of Waterloo, Waterloo, Ontario N2L 3G1, Canada and Institute for Quantum Computing, University of Waterloo, Waterloo, Ontario N2L 3G1, Canada

C. B. Shahi