AVERAGE PARTICLE MULTIPLICITIES IN HADRONIC ${{\mathit W}}$ DECAY

Summed over particle and antiparticle, when appropriate.

$\langle{}\mathit N_{{\mathrm {charged}}}\rangle{}$

INSPIRE   PDGID:
S043CHG
VALUE DOCUMENT ID TECN  COMMENT
$\bf{ 19.39 \pm0.08}$ OUR AVERAGE
$19.38$ $\pm0.05$ $\pm0.08$ 1
ABBIENDI
2006A
 OPAL ${\it{}E}^{\it{}ee}_{\rm{}cm}$= $189 - 209$ GeV
$19.44$ $\pm0.17$ 2
ABREU,P
2000F
 DLPH ${\it{}E}^{\it{}ee}_{\rm{}cm}$= 183+189 GeV
$19.3$ $\pm0.3$ $\pm0.3$ 3
ABBIENDI
1999N
 OPAL ${\it{}E}^{\it{}ee}_{\rm{}cm}$= 183 GeV
$19.23$ $\pm0.74$ 4
ABREU
1998C
 DLPH ${\it{}E}^{\it{}ee}_{\rm{}cm}$= 172 GeV
1  ABBIENDI 2006A measure $\langle \mathit N_{{\mathrm {charged}}}\rangle $ = $38.74$ $\pm0.12$ $\pm0.26$ when both ${{\mathit W}}$ bosons decay hadronically and $\langle \mathit N_{{\mathrm {charged}}}\rangle $ = $19.39$ $\pm0.11$ $\pm0.09$ when one ${{\mathit W}}$ boson decays semileptonically. The value quoted here is obtained under the assumption that there is no color reconnection between ${{\mathit W}}$ bosons; the value is a weighted average taking into account correlations in the systematic uncertainties.
2  ABREU,P 2000F measure $\langle{}\mathit N_{{\mathrm {charged}}}\rangle{}$ = $39.12$ $\pm0.33$ $\pm0.36$ and $38.11$ $\pm0.57$ $\pm0.44$ in the fully hadronic final states at 189 and 183 GeV respectively, and $\langle{}\mathit N_{{\mathrm {charged}}}\rangle{}$ = $19.49$ $\pm0.31$ $\pm0.27$ and $19.78$ $\pm0.49$ $\pm0.43$ in the semileptonic final states. The value quoted is a weighted average without assuming any correlations.
3  ABBIENDI 1999N use the final states ${{\mathit W}^{+}}$ ${{\mathit W}^{-}}$ $\rightarrow$ ${{\mathit q}}{{\overline{\mathit q}}}{{\mathit \ell}}{{\overline{\mathit \nu}}_{{{{\mathit \ell}}}}}$ to derive this value.
4  ABREU 1998C combine results from both the fully hadronic as well semileptonic ${{\mathit W}}{{\mathit W}}$ final states after demonstrating that the ${{\mathit W}}$ decay charged multiplicity is independent of the topology within errors.
References:
ABBIENDI 2006A
EPJ C45 291 Colour Reconnection in ${{\mathit e}^{+}}$ ${{\mathit e}^{-}}$ $\rightarrow$ ${{\mathit W}^{+}}{{\mathit W}^{-}}$ at $\sqrt {s }$ =$180 - 209$ GeV
ABREU,P 2000F
EPJ C18 203 Charged and Identified Particles in the Hadronic Decay of ${{\mathit W}}$ Bosons and in ${{\mathit e}^{+}}$ ${{\mathit e}^{-}}$ $\rightarrow$ ${\mathit {\mathit q}}$ ${\mathit {\overline{\mathit q}}}$ from 130 to 200 GeV
Also
EPJ C25 493 (errat.) Erratum: ABREU,P 2000F Charged and Identified Particles in the Hadronic Decay of ${{\mathit W}}$ Bosons and in ${{\mathit e}^{+}}$ ${{\mathit e}^{-}}$ $\rightarrow$ ${\mathit {\mathit q}}$ ${\mathit {\overline{\mathit q}}}$ from 130 to 200 Gev
ABBIENDI 1999N
PL B453 153 Color Reconnection Studies in ${{\mathit e}^{+}}$ ${{\mathit e}^{-}}$ $\rightarrow$ ${{\mathit W}^{+}}{{\mathit W}^{-}}$ at $\sqrt {s }$ = 183 GeV
ABREU 1998C
PL B416 233 Charged Particle Multiplicity in ${{\mathit e}^{+}}$ ${{\mathit e}^{-}}$ $\rightarrow$ ${\mathit {\mathit q}}$ ${\mathit {\overline{\mathit q}}}$ Events at 161 and 172 GeV and from the Decay of the ${{\mathit W}}$ Boson