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

$\phi _{\mathit AV}$, PHASE OF ${\mathit g}_{{{\mathit A}}}$ RELATIVE TO ${\mathit g}_{{{\mathit V}}}$ INSPIRE search

Time reversal invariance requires this to be 0 or 180$^\circ{}$. This is related to $\mathit D$ given in the next data block and $\lambda $ ${}\equiv$ $\mathit g_{\mathit A}/\mathit g_{\mathit V}$ by sin$(\phi _{\mathit AV})$ ${}\equiv$ $\mathit D(1+3\lambda {}^{2})/2\vert \lambda \vert $; this assumes that $\mathit g_{A}$ and $\mathit g_{V}$ are real.

S017F

VALUE ($^\circ{}$)

CL%

DOCUMENT ID

TECN

COMMENT

$\bf{ 180.017 \pm0.026}$

OUR AVERAGE

$180.012$ $\pm0.028$

CHUPP

2012

CNTR