${{\boldsymbol Z}}$ COUPLINGS TO NEUTRAL LEPTONS

Averaging over neutrino species, the invisible ${{\mathit Z}}$ decay width determines the effective neutrino coupling $\mathit g{}^{{{\mathit \nu}_{{{{\mathit \ell}}}}}}$. For $\mathit g{}^{{{\mathit \nu}_{{e}}}}$ and $\mathit g{}^{{{\mathit \nu}_{{\mu}}}}$, ${{\mathit \nu}_{{e}}}{{\mathit e}}$ and ${{\mathit \nu}_{{\mu}}}{{\mathit e}}$ scattering results are combined with $\mathit g{}^{{{\mathit e}}}_{\mathit A}$ and $\mathit g{}^{{{\mathit e}}}_{\mathit V}$ measurements at the ${{\mathit Z}}$ mass to obtain $\mathit g{}^{{{\mathit \nu}_{{e}}}}$ and $\mathit g{}^{{{\mathit \nu}_{{\mu}}}}$ following NOVIKOV 1993C.

$\boldsymbol g{}^{{{\boldsymbol \nu}_{{\mu}}}}$ INSPIRE search

VALUE DOCUMENT ID TECN  COMMENT
$0.502$ $\pm0.017$ 1
VILAIN
1994
CHM2 From ${{\mathit \nu}_{{\mu}}}{{\mathit e}}$ scattering
1  VILAIN 1994 derive this value from their measurement of the couplings $\mathit g{}^{ {{\mathit e}} {{\mathit \nu}_{{\mu}}} }_{\mathit A}$ = $-0.503$ $\pm0.017$ and $\mathit g{}^{ {{\mathit e}} {{\mathit \nu}_{{\mu}}} }_{\mathit V}$ = $-0.035$ $\pm0.017$ obtained from ${{\mathit \nu}_{{\mu}}}{{\mathit e}}$ scattering. We have re-evaluated this value using the current PDG values for $\mathit g{}^{{{\mathit e}}}_{\mathit A}$ and $\mathit g{}^{{{\mathit e}}}_{\mathit V}$.
  References:
VILAIN 1994
PL B320 203 Flavour Universality of Neutrino Couplings with the ${{\mathit Z}^{0}}$