Number from ${{\mathit e}^{+}}{{\mathit e}^{-}}$ Colliders

Number of Light ${{\mathit \nu}}$ Types from Direct Measurement of Invisible ${{\mathit Z}}$ Width

INSPIRE   PDGID:
S007NI
In the following, the invisible ${{\mathit Z}}$ width is obtained from studies of single-photon events from the reaction ${{\mathit e}^{+}}$ ${{\mathit e}^{-}}$ $\rightarrow$ ${{\mathit \nu}}{{\overline{\mathit \nu}}}{{\mathit \gamma}}$. All are obtained from LEP runs in the ${\it{}E}^{\it{}ee}_{\rm{}cm}$ range $88 - 209$ GeV.
VALUE DOCUMENT ID TECN  COMMENT
$\bf{ 2.92 \pm0.05}$ OUR AVERAGE  Error includes scale factor of 1.2.
$2.84$ $\pm0.10$ $\pm0.14$
ABDALLAH
2005B
 DLPH $\sqrt {s }$ = $180 - 209$ GeV
$2.98$ $\pm0.05$ $\pm0.04$
ACHARD
2004E
 L3 1990-2000 LEP runs
$2.86$ $\pm0.09$
HEISTER
2003C
 ALEP $\sqrt {s }$ = $189 - 209$ GeV
$2.69$ $\pm0.13$ $\pm0.11$
ABBIENDI,G
2000D
 OPAL 1998 LEP run
$2.89$ $\pm0.32$ $\pm0.19$
ABREU
1997J
 DLPH 1993--1994 LEP runs
$3.23$ $\pm0.16$ $\pm0.10$
AKERS
1995C
 OPAL $1990 - 1992$ LEP runs
$2.68$ $\pm0.20$ $\pm0.20$
BUSKULIC
1993L
 ALEP $1990 - 1991$ LEP runs
• • We do not use the following data for averages, fits, limits, etc. • •
$2.84$ $\pm0.15$ $\pm0.14$
ABREU
2000Z
 DLPH $1997 - 1998$ LEP runs
$3.01$ $\pm0.08$
ACCIARRI
1999R
 L3 $1991 - 1998$ LEP runs
$3.1$ $\pm0.6$ $\pm0.1$
ADAM
1996C
 DLPH $\sqrt {\mathit s }$ = 130, 136 GeV
References