The
OPAL
collaboration
Acton, P.D.
;
Alexander, G.
;
Allison, John
;
*et al. *

Z.Phys.C 58 (1993) 219-238, 1993.

https://inspirehep.net/literature/352696
Inspire Record
352696
DOI
10.17182/hepdata.14495
https://doi.org/10.17182/hepdata.14495
New measurements of the hadronic and leptonic cross sections and of the leptonic forward-backward asymmetries ine+e− collisions are presented. The analysis includes data recorded up to the end of 1991 by the OPAL experiment at LEP, with centre-of-mass energies within ±3 GeV of the Z0 mass. The results are based on a recorded total of 454 000 hadronic and 58 000 leptonic events. A model independent analysis of Z0 parameters based on an extension of the improved Born approximation is presented leading to test of lepton universality and an interpretation of the results within the Standard Model framework. The determination of the mass and width of the Z0 benefit from an improved understanding of the LEP energy calibration.

5
data tables
match query

Additional systematic error of 0.003.

Forward-backward asymmetry from counting number of events. Additional systematic error of 0.003.

2
data tables
match query

Asymmetries. Systematic error is 1 pct.

Asymmetries. Systematic error is 1 pct.

The
OPAL
collaboration
Akrawy, M.Z.
;
Alexander, G.
;
Allison, J.
;
*et al. *

Phys.Lett.B 247 (1990) 458-472, 1990.

https://inspirehep.net/literature/297139
Inspire Record
297139
DOI
10.17182/hepdata.29630
https://doi.org/10.17182/hepdata.29630
The couplings of the Z 0 to charged leptons are studied using measurements of the lepton pair cross sections and forward-backward asymmetries at centre of mass energies near to the mass of the Z 0 . The data are consistent with lepton universality. Using a parametrisation of the lepton pair differential cross section which assumes that the Z 0 has only vector and axial couplings to leptons, the charged leptonic partial decay width of the Z 0 is determined to be Г ol+ol− = 83.1±1.9 MeV and the square of the product of the effective axial vector and vector coupling constants of the Z 0 to charged leptons to be a ̌ 2 ol v ̌ 2 ol = 0.0039± 0.0083 , in agreement with the standard model. A parametrisation in the form of the improved Born approximation gives effective leptonic axial vector and vector coupling constants a ̌ 2 ol = 0.998±0.024 and v ̌ 2 ol = 0.0044±0.0083 . In the framework of the standard model, the values of the parameters ϱ z and sin 2 θ w are found to be 0.998±0.024 and 0.233 +0.045 −0.012 respectively. Using the relationship in the minimal standard model between ϱ z and sin 2 θ w , the results sin 2 θ SM w = 0.233 +0.007 −0.006 is obtained. Our previously published measurement of the ratio of the hadronic to the leptonic partial width of the Z 0 is update: R z = 21.72 +0.71 −0.65 .

3
data tables
match query

Forward-backward asymmetry corrected for kinematic cuts. Errors have systematics folded.

Forward-backward asymmetry. Statistical errors only.

Forward-backward asymmetry. Statistical errors only.

The
VENUS
collaboration
Miura, M.
;
Odaka, S.
;
Arima, T.
;
*et al. *

Phys.Rev.D 57 (1998) 5345-5362, 1998.

https://inspirehep.net/literature/452097
Inspire Record
452097
DOI
10.17182/hepdata.27142
https://doi.org/10.17182/hepdata.27142
The reaction e+e−→μ+μ− has been measured at s=57.77GeV, based on 289.6±2.6 pb−1 data collected with the VENUS detector at TRISTAN. The production cross section is measured in bins of the production angle within an angular acceptance of |cosθ|<~0.75, according to a model-independent definition. The result is consistent with the prediction of the standard electroweak theory. Although a trend in measurements at lower energies that the total cross section tends to be smaller than the prediction remains, the discrepancy is not significant. The model-independent result is converted to the differential cross section in the effective-Born scheme by unfolding photon-radiation effects. This result can be extrapolated to quantities for the full solid angle as σtotEB=30.05±0.59 pb and AFBEB=−0.350±0.017, by imposing an ordinary assumption on the production-angle dependence. The converted results are used to set constraints on extensions of the standard theory. S-matrix parametrization, and possible contributions from contact interactions and heavy neutral-scalar exchanges are examined.

1
data table
match query

Total cross section and forward backward asymmetry results in the effective-Born scheme.

The
DELPHI
collaboration
Abreu, P.
;
Adam, W.
;
Adami, F.
;
*et al. *

Phys.Lett.B 260 (1991) 240-248, 1991.

https://inspirehep.net/literature/314619
Inspire Record
314619
DOI
10.17182/hepdata.29420
https://doi.org/10.17182/hepdata.29420
Measurements of the cross section and forward-backward asymmetry for the reaction e + e − → μ + μ − using the DELPHI detector at LEP are presented. The data come from a scan around the Z 0 peak at seven centre of mass energies, giving a sample of 3858 events in the polar angle region 22° < θ < 158°. From a fit to the cross section for 43° < θ < 137°, a polar angle region for which the absolute efficiency has been determined, the square root of the product of the Z 0 → e + e − and Z 0 → μ + μ − partial widths is determined to be (Γ e Γ μ ) 1 2 = 85.0 ± 0.9( stat. ) ± 0.8( syst. ) MeV . From this measurement of the partial width, the value of the effective weak mixing angle is determined to be sin 2 ( θ w ) = 0.2267 ± 0.0037 . The ratio of the hadronic to muon pair partial widths is found to be Γ h / Γ μ = 19.89 ± 0.40(stat.) ± 0.19(syst.). The forward-backward asymmetry at the resonance peak energy E CMS = 91.22 GeV is found to be A FB = 0.028 ± 0.020(stat.) ± 0.005(syst.). From a combined fit to the cross section and forward-backward asymmetry data, the products of the electron and muon vector and axial-vector coupling constants are determined to be V e V μ = 0.0024 ± 0.0015(stat.) ± 0.0004(syst.) and A e A μ = 0.253 ± 0.003(stat.) ± 0.003 (syst.). The results are in good agreement with the expectations of the minimal standard model.

1
data table
match query

The
L3
collaboration
Adeva, B.
;
Adriani, O.
;
Aguilar-Benitez, M.
;
*et al. *

Phys.Lett.B 236 (1990) 109-115, 1990.

https://inspirehep.net/literature/283470
Inspire Record
283470
DOI
10.17182/hepdata.29715
https://doi.org/10.17182/hepdata.29715
We have measured both the rates and the forward-backward asymmetry of ℓ + ℓ − from Z 0 →ℓ + ℓ − (where ℓ= μ , τ ) with the L3 detector. We obtained Γ ℓℓ =88±4±3 MeV and the vector neutral current coupling constant, g v =0.00±0.07 and the axial vector neutral current coupling constant, g A =−0.515±0.015.

1
data table
match query

No description provided.

The
CELLO
collaboration
Behrend, H.J.
;
Criegee, L.
;
Field, J.H.
;
*et al. *

Z.Phys.C 51 (1991) 149-156, 1991.

https://inspirehep.net/literature/301727
Inspire Record
301727
DOI
10.17182/hepdata.14981
https://doi.org/10.17182/hepdata.14981
Differential cross section data of the CELLO experiment on pair production of muons, taus, and heavy quarks ine+e−-annihilation are presented and analysed, together with our data on Bhabha scattering, in terms of compositeness effects characterized by the mass scale Λ. We discuss difficulties in the combination of limits Λ from different experiments. The appropriate parameter to combine different results turns out to be ɛ=±1/Λ2, which is in contrast to Λ Gaussian distributed.

2
data tables
match query

Charge asymmetry for charm quarks derived from the differential cross section data.

Charge asymmetry for bottom quarks derived from the differential cross section data.

The
CELLO
collaboration
Behrend, H.J.
;
Chen, C.
;
Fenner, H.
;
*et al. *

Z.Phys.C 16 (1983) 301, 1983.

https://inspirehep.net/literature/180756
Inspire Record
180756
DOI
10.17182/hepdata.16385
https://doi.org/10.17182/hepdata.16385
Differential cross sections fore+e−→e+e−, τ+, τ- measured with the CELLO detector at\(\left\langle {\sqrt s } \right\rangle= 34.2GeV\) have been analyzed for electroweak contributions. Vector and axial vector coupling constants were obtained in a simultaneous fit to the three differential cross sections assuming a universal weak interaction for the charged leptons. The results,v2=−0.12±0.33 anda2=1.22±0.47, are in good agreement with predictions from the standardSU(2)×U(1) model for\(\sin ^2 \theta _w= 0.228\). Combining this result with neutrino-electron scattering data gives a unique axial vector dominated solution for the leptonic weak couplings. Assuming the validity of the standard model, a value of\(\sin ^2 \theta _w= 0.21_{ - 0.09}^{ + 0.14}\) is obtained for the electroweak mixing angle. Additional vector currents are not observed (C<0.031 is obtained at the 95% C.L.).

1
data table
match query

The
CELLO
collaboration
Behrend, H.J.
;
Chen, C.
;
Field, J.H.
;
*et al. *

Z.Phys.C 14 (1982) 283, 1982.

https://inspirehep.net/literature/177216
Inspire Record
177216
DOI
10.17182/hepdata.16414
https://doi.org/10.17182/hepdata.16414
The reaction (e+e−→μ+μ−) has been measured between\(\sqrt S= 14.0\) and\(\sqrt S= 36.4\). The total cross section result is in good agreement with the QED prediction and the following Λ values have been obtained:Λ+=186 GeV,Λ−=101 GeV. The angular distribution at high energy (\(\left( {\left. {\left\langle {\sqrt S } \right.} \right\rangle= 34.2 GeV} \right)\)) shows a fitted charge asymmetry of −0.064±0.064 in agreement with theW-S model prediction of −0.092, corresponding to an axial coupling parametera2=4ga2=0.69±0.69.

1
data table
match query

Fernandez, E.
;
Ford, William T.
;
Read, Alexander L.
;
*et al. *

SLAC-PUB-3133, 1983.

https://inspirehep.net/literature/190846
Inspire Record
190846
DOI
10.17182/hepdata.18659
https://doi.org/10.17182/hepdata.18659
None

1
data table
match query

Data extrapolated to full solid angle.