${{\mathit n}}$ $\rightarrow$ ${{\mathit p}}{{\mathit e}^{-}}{{\overline{\mathit \nu}}_{{{e}}}}$ DECAY PARAMETERS

See the above “Note on Baryon Decay Parameters.” For discussions of recent results, see the references cited at the beginning of the section on the neutron mean life. For discussions of the values of the weak coupling constants ${\mathit g}_{{{\mathit A}}}$ and ${\mathit g}_{{{\mathit V}}}$ obtained using the neutron lifetime and asymmetry parameter$~\mathit A$, comparisons with other methods of obtaining these constants, and implications for particle physics and for astrophysics, see DUBBERS 1991 and WOOLCOCK 1991. For tests of the $\mathit V−\mathit A$ theory of neutron decay, see EROZOLIMSKII 1991B, MOSTOVOI 1996, NICO 2005, SEVERIJNS 2006, and ABELE 2008.

${{\overline{\mathit \nu}}_{{{e}}}}$ ASYMMETRY PARAMETER $\mathit B$ INSPIRE search

This is the neutron-spin antineutrino-momentum correlation coefficient. In the Standard Model, $\mathit B$ is related to $\lambda {}\equiv\mathit g_{A}/\mathit g_{V}$ by $\mathit B$ = 2$\lambda (\lambda $ $−$ 1) $/$ (1 + 3$\lambda {}^{2}$); this assumes that $\mathit g_{A}$ and $\mathit g_{V}$ are real.

S017NA

VALUE

DOCUMENT ID

TECN

COMMENT

$\bf{ 0.9807 \pm0.0030}$

OUR AVERAGE

$0.9802$ $\pm0.0034$ $\pm0.0036$

SCHUMANN

2007

CNTR

Cold ${{\mathit n}}$, polarized