${{\boldsymbol \Lambda}}$ DECAY PARAMETERS

See the ``Note on Baryon Decay Parameters'' in the neutron Listings. Some early results have been omitted.

${\boldsymbol g}_{{{\boldsymbol A}}}$ $/$ ${\boldsymbol g}_{{{\boldsymbol V}}}$ FOR ${{\boldsymbol \Lambda}}$ $\rightarrow$ ${{\boldsymbol p}}{{\boldsymbol e}^{-}}{{\overline{\boldsymbol \nu}}_{{e}}}$ INSPIRE search

Measurements with fewer than 500 events have been omitted. Where necessary, signs have been changed to agree with our conventions, which are given in the ``Note on Baryon Decay Parameters'' in the neutron Listings. The measurements all assume that the form factor $\mathit g_{2}$ = 0. See also the footnote on DWORKIN 1990 .
VALUE EVTS DOCUMENT ID TECN  COMMENT
$\bf{ -0.718 \pm0.015}$ OUR AVERAGE
$-0.719$ $\pm0.016$ $\pm0.012$ 37k 1
DWORKIN
1990
SPEC ${{\mathit e}}{{\mathit \nu}}$ angular corr.
$-0.70$ $\pm0.03$ 7111
BOURQUIN
1983
SPEC ${{\mathit \Xi}}$ $\rightarrow$ ${{\mathit \Lambda}}{{\mathit \pi}^{-}}$
$-0.734$ $\pm0.031$ 10k 2
WISE
1981
SPEC ${{\mathit e}}{{\mathit \nu}}$ angular correl.
• • • We do not use the following data for averages, fits, limits, etc. • • •
$-0.63$ $\pm0.06$ 817
ALTHOFF
1973
OSPK Polarized ${{\mathit \Lambda}}$
1  The tabulated result assumes the weak-magnetism coupling $\mathit w$ ${}\equiv$ ${\mathit g}_{{{\mathit w}}}(0)/{\mathit g}_{{{\mathit v}}}$(0) to be $0.97$, as given by the CVC hypothesis and as assumed by the other listed measurements. However, DWORKIN 1990 $\mathit measures$ $\mathit w$ to be $0.15$ $\pm0.30$, and then ${\mathit g}_{{{\mathit A}}}/{\mathit g}_{{{\mathit V}}}$ = $-0.731$ $\pm0.016$.
2  This experiment measures only the absolute value of ${\mathit g}_{{{\mathit A}}}/{\mathit g}_{{{\mathit V}}}$.
  References:
DWORKIN 1990
PR D41 780 High Statistics Measurement of $\mathit g_{a}$/g$_{v}$ in ${{\mathit \Lambda}}$ $\rightarrow$ ${{\mathit p}}{{\mathit e}^{-}}{{\overline{\mathit \nu}}}$
BOURQUIN 1983
ZPHY C21 1 Measurements of Hyperon Semileptonic Decays at the CERN Super Proton Synchrotron. 2. The ${{\mathit \Lambda}}$ $\rightarrow$ ${{\mathit p}}{{\mathit e}^{-}}{{\overline{\mathit \nu}}_{{e}}}$ , ${{\mathit \Xi}^{-}}$ $\rightarrow$ ${{\mathit \Lambda}}{{\mathit e}^{-}}{{\overline{\mathit \nu}}_{{e}}}$ , and ${{\mathit \Xi}^{-}}$ $\rightarrow$ ${{\mathit \Sigma}^{0}}{{\mathit e}^{-}}{{\overline{\mathit \nu}}_{{e}}}$ Decay Modes
WISE 1981
PL 98B 123 Precise Measurement of the Ratio of the Axial Vector Coupling to Vector Coupling in ${{\mathit \Lambda}^{0}}$ $\rightarrow$ ${{\mathit p}}{{\mathit e}^{-}}{{\overline{\mathit \nu}}_{{e}}}$
ALTHOFF 1973
PL 43B 237 $\beta $ Decay of Polarized ${{\mathit \Lambda}}$ Hyperons III. Correlations in the ${{\mathit \Lambda}}$ Centre-of-Mass System and the Proton Recoil Spectrum