${{\mathit N}}$ BARYONS
($\mathit S$ = 0, $\mathit I$ = 1/2)

${{\mathit p}}$, ${{\mathit N}^{+}}$ = ${\mathit {\mathit u}}$ ${\mathit {\mathit u}}$ ${\mathit {\mathit d}}$; ${{\mathit n}}$, ${{\mathit N}^{0}}$ = ${\mathit {\mathit u}}$ ${\mathit {\mathit d}}$ ${\mathit {\mathit d}}$
INSPIRE search

${{\mathit n}}$ $I(J^P)$ = $1/2(1/2^{+})$

We have omitted some results that have been superseded by later experiments. See our earlier editions. Anyone interested in the neutron should look at these two new review articles: D. Dubbers and M.G. Schmidt, ``The neutron and its role in cosmology and particle physics,'' Reviews of Modern Physics 83 1111 (2011); and F.E. Wietfeldt and G.L. Greene, ``The neutron lifetime,'' Reviews of Modern Physics 83 1173 (2011).
Baryon Decay Parameters
${{\mathit n}}$ MASS (atomic mass units u)   $1.0086649159 \pm0.0000000005$ u 
${{\mathit n}}$ MASS (MeV)   $939.565413 \pm0.000006$ MeV 
${{\overline{\mathit n}}}$ MASS   $939.49 \pm0.05$ MeV 
(${\mathit m}_{{{\mathit n}}}–{\mathit m}_{{{\overline{\mathit n}}}}$ )/ ${\mathit m}_{{{\mathit n}}}$   $(9 \pm6) \times 10^{-5}$  
${\mathit m}_{{{\mathit n}}}–{\mathit m}_{{{\mathit p}}}$
${\mathit m}_{{{\mathit n}}}–{\mathit m}_{{{\mathit p}}}$   $1.2933321 \pm0.0000005$ MeV 
${{\mathit n}}$ MEAN LIFE   $880.2 \pm1.0$ s (S = 1.9)
${{\mathit n}}$ MAGNETIC MOMENT   $-1.9130427 \pm0.0000005$ $\mu _{\mathit N}$ 
${{\mathit n}}$ ELECTRIC DIPOLE MOMENT   $<0.30 \times 10^{-25}$ $\mathit e~$cm  CL=90.0%
${{\mathit n}}$ MEAN-SQUARE CHARGE RADIUS   $-0.1161 \pm0.0022$ fm${}^{2}$ (S = 1.3)
${{\mathit n}}$ MAGNETIC RADIUS   $0.864 {}^{+0.009}_{-0.008}$ fm 
${{\mathit n}}$ ELECTRIC POLARIZABILITY ${{\mathit \alpha}_{{n}}}$   $0.00118 \pm0.00011$ fm${}^{3}$ 
${{\mathit n}}$ MAGNETIC POLARIZABILITY ${{\mathit \beta}_{{n}}}$   $(3.7 \pm1.2) \times 10^{-4}$ fm${}^{3}$ 
${{\mathit n}}$ CHARGE   $(-2 \pm8) \times 10^{-22}$ $\mathit e$ 
LIMIT ON ${{\mathit n}}{{\overline{\mathit n}}}$ OSCILLATIONS
Mean Time for ${{\mathit n}}{{\overline{\mathit n}}}$ Transition in Vacuum   $>2.7 \times 10^{8}$ s  CL=90.0%
LIMIT ON ${{\mathit n}}{{\mathit n}^{\,'}}$ OSCILLATIONS   $> 414$ s  CL=90.0%
${{\mathit n}}$ $\rightarrow$ ${{\mathit p}}{{\mathit e}^{-}}{{\overline{\mathit \nu}}_{{e}}}$ DECAY PARAMETERS
$\lambda {}\equiv{\mathit g}_{{{\mathit A}}}$ $/$ ${\mathit g}_{{{\mathit V}}}$   $-1.2723 \pm0.0023$  (S = 2.2)
${{\mathit e}^{-}}$ ASYMMETRY PARAMETER $\mathit A$   $-0.1184 \pm0.0010$  (S = 2.4)
${{\overline{\mathit \nu}}_{{e}}}$ ASYMMETRY PARAMETER $\mathit B$   $0.9807 \pm0.0030$  
PROTON ASYMMETRY PARAMETER $\mathit C$   $-0.2377 \pm0.0026$  
${{\mathit e}}-{{\overline{\mathit \nu}}_{{e}}}$ ANGULAR CORRELATION COEFFICIENT $\mathit a$   $-0.103 \pm0.004$  
$\phi _{\mathit AV}$, PHASE OF ${\mathit g}_{{{\mathit A}}}$ RELATIVE TO ${\mathit g}_{{{\mathit V}}}$   $180.017 \pm0.026$ $^\circ{}$ 
TRIPLE CORRELATION COEFFICIENT $\mathit D$   $(-1.2 \pm2.0) \times 10^{-4}$  
TRIPLE CORRELATION COEFFICIENT $\mathit R$   $0.004 \pm0.013$  
$\Gamma_{1}$ ${{\mathit p}}{{\mathit e}^{-}}{{\overline{\mathit \nu}}_{{e}}}$ $(100)\%$1
$\Gamma_{2}$ ${{\mathit p}}{{\mathit e}^{-}}{{\overline{\mathit \nu}}_{{e}}}{{\mathit \gamma}}$ [1]$(9.2\pm0.7)\times 10^{-3}$1
$\Gamma_{3}$ hydrogen-atom ${{\overline{\mathit \nu}}_{{e}}}$ 1