Internal consistency of neutron coherent scattering length measurements from neutron interferometry and from neutron gravity reflectometry
Abstract
Many theories beyond the Standard Model postulate short-range modifications to gravity which produce deviations of Newton's gravitational potential from a strict 1 /r dependence. It is common to analyze experiments searching for these modifications using a potential of the form V'(r )=-G/M m r [1 +α exp (-r /λ ) ] . The best present constraints on α for λ <100 nm come from neutron scattering and often employ comparisons of different measurements of the coherent neutron scattering amplitudes b . We analyze the internal consistency of existing data from two different types of measurements of low-energy neutron scattering amplitudes: neutron interferometry, which involves squared momentum transfers q2=0 , and neutron gravity reflectometry, which involves squared momentum transfers q2=8 m Vopt where m is the neutron mass and Vopt is the neutron optical potential of the medium. We show that the fractional difference Δ/b |b | averaged over the seven elements where high precision data exist on the same material from both measurement methods is [2.2 ±1.4 ]×10-4. We also show that Δ/b |b | for these data is insensitive both to exotic Yukawa interactions and also to the electromagnetic neutron-atom interactions proportional to the neutron-electron scattering length bn e and the neutron polarizability scattering amplitude bpol. This result will be useful in any future global analyses of neutron scattering data to determine bn e and bound α and λ . We also discuss how various neutron interferometric and scattering techniques with cold and ultracold neutrons can be used to improve the precision of b measurements and make some specific proposals.
- Publication:
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Physical Review D
- Pub Date:
- March 2020
- DOI:
- 10.1103/PhysRevD.101.062004
- arXiv:
- arXiv:1910.14271
- Bibcode:
- 2020PhRvD.101f2004S
- Keywords:
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- Nuclear Experiment;
- High Energy Physics - Experiment
- E-Print:
- 13 pages, 1 figure