#### Number of Light ${{\mathit \nu}}$ Types

VALUE DOCUMENT ID TECN
$2.9963$ $\pm0.0074$ 1
 2020
• • We do not use the following data for averages, fits, limits, etc. • •
$2.9918$ $\pm0.0081$ 2
 2020
$2.9840$ $\pm0.0082$ 3
 2006
RVUE
$3.00$ $\pm0.05$ 4
 1992
RVUE
 1 JANOT 2020 applies a correction to LEP-SLC 2006 using an updated Bhabha cross section calculation. This result also includes a correction to account for correlated luminosity bias as presented in VOUTSINAS 2020 .
 2 VOUTSINAS 2020 applies a correction to LEP-SLC 2006 to account for correlated luminosity bias.
 3 Combined fit from ALEPH, DELPHI, L3 and OPAL Experiments.
 4 Simultaneous fits to all measured cross section data from all four LEP experiments.
References:
 JANOT 2020
PL B803 135319 Improved Bhabha cross section at LEP and the number of light neutrino species
 VOUTSINAS 2020
PL B800 135068 Beam-beam effects on the luminosity measurement at LEP and the number of light neutrino species
 LEP-SLC 2006
PRPL 427 257 Precision Electroweak Measurements on the ${{\mathit Z}}$ Resonance
 LEP 1992
PL B276 247 Electroweak Parameters of the ${{\mathit Z}^{0}}$ Resonance and the Standard Model