Internal consistency of neutron coherent scattering length measurements from neutron interferometry and from neutron gravity reflectometry
| Autor: | J. Apanavicius, E. Alexeev, A. Reid, M. Peters, J. S. Devaney, W. M. Snow, B. Shen, K. A. Dickerson, J. Woo, Christopher C. Haddock, H. Drabek |
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| Rok vydání: | 2020 |
| Předmět: | |
| Zdroj: | Physical Review D. 101 |
| ISSN: | 2470-0029 2470-0010 |
| DOI: | 10.1103/physrevd.101.062004 |
| Popis: | 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 ${V}^{\ensuremath{'}}(r)=\phantom{\rule{0ex}{0ex}}\ensuremath{-}\frac{GMm}{r}[1+\ensuremath{\alpha}\mathrm{exp}(\ensuremath{-}r/\ensuremath{\lambda})]$. The best present constraints on $\ensuremath{\alpha}$ for $\ensuremath{\lambda}l100\text{ }\text{ }\mathrm{nm}$ 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 ${q}^{2}=0$, and neutron gravity reflectometry, which involves squared momentum transfers ${q}^{2}=8m{V}_{\mathrm{opt}}$ where $m$ is the neutron mass and ${V}_{\mathrm{opt}}$ is the neutron optical potential of the medium. We show that the fractional difference $\frac{\mathrm{\ensuremath{\Delta}}b}{|b|}$ averaged over the seven elements where high precision data exist on the same material from both measurement methods is $[2.2\ifmmode\pm\else\textpm\fi{}1.4]\ifmmode\times\else\texttimes\fi{}{10}^{\ensuremath{-}4}$. We also show that $\frac{\mathrm{\ensuremath{\Delta}}b}{|b|}$ 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 ${b}_{ne}$ and the neutron polarizability scattering amplitude ${b}_{\mathrm{pol}}$. This result will be useful in any future global analyses of neutron scattering data to determine ${b}_{ne}$ and bound $\ensuremath{\alpha}$ and $\ensuremath{\lambda}$. 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. |
| Databáze: | OpenAIRE |
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