# ${{\boldsymbol n}}$ MEAN-SQUARE CHARGE RADIUS INSPIRE search

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
$\bf{ -0.1161 \pm0.0022}$ OUR AVERAGE  Error includes scale factor of 1.3.
$-0.115$ $\pm0.002$ $\pm0.003$
 1997
${{\mathit n}}{{\mathit e}}$ scattering (Pb)
$-0.124$ $\pm0.003$ $\pm0.005$
 1997
${{\mathit n}}{{\mathit e}}$ scattering (Bi)
$-0.114$ $\pm0.003$
 1995
${{\mathit n}}{{\mathit e}}$ scattering (Pb, Bi)
$-0.134$ $\pm0.009$
 1986
${{\mathit n}}{{\mathit e}}$ scattering (Bi)
$-0.115$ $\pm0.003$ 1
 1973
${{\mathit n}}{{\mathit e}}$ scattering (Ne, Ar, Kr, Xe)
• • • We do not use the following data for averages, fits, limits, etc. • • •
$-0.117$ ${}^{+0.007}_{-0.011}$
 2007
Dispersion analysis
$-0.113$ $\pm0.003$ $\pm0.004$
 1995
${{\mathit n}}{{\mathit e}}$ scattering (Pb)
$-0.114$ $\pm0.003$
 1986
${{\mathit n}}{{\mathit e}}$ scattering (Pb, Bi)
$-0.118$ $\pm0.002$
 1976
${{\mathit n}}{{\mathit e}}$ scattering (Pb)
$-0.120$ $\pm0.002$
 1976
${{\mathit n}}{{\mathit e}}$ scattering (Bi)
$-0.116$ $\pm0.003$
 1966
${{\mathit n}}{{\mathit e}}$ scattering (Ne, Ar, Kr, Xe)
1  This value is as corrected by KOESTER 1976 .

${{\mathit n}}$ mean-square charge radius
References:
 BELUSHKIN 2007
PR C75 035202 Dispersion Analysis of the Nucleon Form Factors Including Meson Continua
 KOPECKY 1997
PR C56 2229 Neutron Charge Radius Determined from the Energy Dependence of the Neutron Transmission of Liquid ${}^{208}\mathrm {Pb}$ and ${}^{209}\mathrm {Bi}$
 KOESTER 1995
PR C51 3363 Neutrino Electron Scattering Length and Electric Polarizability of the Neutron Derived from Cross Sections of Bismuth and of Lead and its Isotopes
 KOPECKY 1995
PRL 74 2427 New Measurement of the Charge Radius of the Neutron
 ALEKSANDROV 1986
SJNP 44 900 Neutron RMS Radius and Electric Polarizability from Data on the Interaction of Slow Neutrons with Bismuth
 KOESTER 1986
Physica B137 282 Neutron Scattering Lengths and Neutron-Electron Interaction
 KOESTER 1976
PRL 36 1021 Measurement of the Neutron-Electron Interaction by the Scattering of Neutrons by Lead and Bismuth
 KROHN 1973
PR D8 1305 Reconsiderations of the Electron-Neutron Scattering Length as Measured by the Scattering of Thermal Neutrons by Noble Gases
 KROHN 1966
PR 148 1303 Measurement of the Electron-Neutron Interaction by the Asymmetrical Scattering of Thermal Neutrons by Noble Gases