${{\mathit n}}$ $\rightarrow$ ${{\mathit p}}{{\mathit e}^{-}}{{\overline{\mathit \nu}}_{{{e}}}}$ 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   PDGID:
S017NA
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.
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
$0.967$ $\pm0.006$ $\pm0.010$
KREUZ
2005
CNTR Cold ${{\mathit n}}$, polarized
$0.9801$ $\pm0.0046$
SEREBROV
1998
CNTR Cold ${{\mathit n}}$, polarized
$0.9894$ $\pm0.0083$
KUZNETSOV
1995
CNTR Cold ${{\mathit n}}$, polarized
$1.00$ $\pm0.05$
CHRISTENSEN
1970
CNTR Cold ${{\mathit n}}$, polarized
$0.995$ $\pm0.034$
EROZOLIMSKII
1970C
CNTR Cold ${{\mathit n}}$, polarized
• • We do not use the following data for averages, fits, limits, etc. • •
$0.9876$ $\pm0.0004$ 1
MOSTOVOI
2001
CNTR Inferred
1  MOSTOVOI 2001 calculates this from its measurement of $\lambda =\mathit g_{\mathit A}/\mathit g_{\mathit V}$ above.
References