${{\mathit n}}$ MEAN-SQUARE CHARGE RADIUS

INSPIRE   PDGID:
S017MCR
The mean-square charge radius of the neutron, $\langle{}\mathit r{}^{2}_{{{\mathit n}}}\rangle{}$, is related to the neutron-electron scattering length $\mathit b_{{{\mathit n}} {{\mathit e}}}$ by $\langle{}\mathit r{}^{2}_{{{\mathit n}}}\rangle{}$ = 3(${\mathit m}_{{{\mathit e}}}\mathit a_{0}/{\mathit m}_{{{\mathit n}}})\mathit b_{{{\mathit n}} {{\mathit e}}}$, where ${\mathit m}_{{{\mathit e}}}$ and ${\mathit m}_{{{\mathit n}}}$ are the masses of the electron and neutron, and $\mathit a_{0}$ is the Bohr radius. Numerically, $\langle{}\mathit r{}^{2}_{{{\mathit n}}}\rangle{}$ = $86.34~\mathit b_{{{\mathit n}} {{\mathit e}}}$, if we use $\mathit a_{0}$ for a nucleus with infinite mass.
VALUE (fm${}^{2}$) DOCUMENT ID  COMMENT
$\bf{ -0.1155 \pm0.0017}$ OUR AVERAGE
$-0.115$ $\pm0.002$ $\pm0.003$
KOPECKY
1997
${{\mathit n}}{{\mathit e}}$ scattering (Pb)
$-0.124$ $\pm0.003$ $\pm0.005$
KOPECKY
1997
${{\mathit n}}{{\mathit e}}$ scattering (Bi)
$-0.114$ $\pm0.003$
KOESTER
1995
${{\mathit n}}{{\mathit e}}$ scattering (Pb, Bi)
$-0.115$ $\pm0.003$ 1
KROHN
1973
${{\mathit n}}{{\mathit e}}$ scattering (Ne, Ar, Kr, Xe)
• • We do not use the following data for averages, fits, limits, etc. • •
$-0.1101$ $\pm0.0089$ 2
HEACOCK
2021
${{\mathit n}}$ interferometry
$-0.106$ ${}^{+0.007}_{-0.005}$ 3
FILIN
2020
chiral EFT analysis
$-0.117$ ${}^{+0.007}_{-0.011}$
BELUSHKIN
2007
Dispersion analysis
$-0.113$ $\pm0.003$ $\pm0.004$
KOPECKY
1995
${{\mathit n}}{{\mathit e}}$ scattering (Pb)
$-0.134$ $\pm0.009$
ALEKSANDROV
1986
${{\mathit n}}{{\mathit e}}$ scattering (Bi)
$-0.114$ $\pm0.003$
KOESTER
1986
${{\mathit n}}{{\mathit e}}$ scattering (Pb, Bi)
$-0.118$ $\pm0.002$
KOESTER
1976
${{\mathit n}}{{\mathit e}}$ scattering (Pb)
$-0.120$ $\pm0.002$
KOESTER
1976
${{\mathit n}}{{\mathit e}}$ scattering (Bi)
$-0.116$ $\pm0.003$
KROHN
1966
${{\mathit n}}{{\mathit e}}$ scattering (Ne, Ar, Kr, Xe)
1  KROHN 1973 measured $-0.112$ $\pm0.003$ fm${}^{2}$. This value is as corrected by KOESTER 1976.
2  HEACOCK 2021 extract the value from Pendelloesung interferometry to measure the neutron structure factors of silicon. This value is strongly anti-correlated with the mean-square thermal atomic displacement.
3  FILIN 2020 extract the value based on their chiral-EFT calculation of the deuteron structure radius and use as input the atomic data for the difference of the deuteron and proton charge radii.
References