# ${{\boldsymbol Z}}$ 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.

# $\boldsymbol g{}^{{{\boldsymbol \nu}_{{{{\boldsymbol \ell}}}}}}$ INSPIRE search

VALUE DOCUMENT ID  COMMENT
$0.50076$ $\pm0.00076$ 1
 2006
${\it{}E}^{\it{}ee}_{\rm{}cm}$ = $88 - 94$ GeV
1  From invisible ${{\mathit Z}}$-decay width.
References:
 LEP-SLC 2006
PRPL 427 257 Precision Electroweak Measurements on the ${{\mathit Z}}$ Resonance