Measurement of cross sections and leptonic forward-backward asymmetries at the Z pole and determination of electroweak parameters
We report on the measurement of the leptonic and hadronic cross sections and leptonic forward-backward asymmetries at theZ peak with the L3 detector at LEP. The total luminosity of 40.8 pb<sup>−1</sup> collected in the years 1990, 1991 and 1992 corresponds to 1.09·10<sup>6</sup&...
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| Formato: | Articulo |
| Lenguaje: | Inglés |
| Publicado: |
1994
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| Acceso en línea: | http://sedici.unlp.edu.ar/handle/10915/81046 |
| Aporte de: |
| id |
I19-R120-10915-81046 |
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| record_format |
dspace |
| institution |
Universidad Nacional de La Plata |
| institution_str |
I-19 |
| repository_str |
R-120 |
| collection |
SEDICI (UNLP) |
| language |
Inglés |
| topic |
Ciencias Exactas Física Partículas Elementales L3 detector la̵rge hadron collider |
| spellingShingle |
Ciencias Exactas Física Partículas Elementales L3 detector la̵rge hadron collider Dova, María Teresa L3 Collaboration Measurement of cross sections and leptonic forward-backward asymmetries at the Z pole and determination of electroweak parameters |
| topic_facet |
Ciencias Exactas Física Partículas Elementales L3 detector la̵rge hadron collider |
| description |
We report on the measurement of the leptonic and hadronic cross sections and leptonic forward-backward asymmetries at theZ peak with the L3 detector at LEP. The total luminosity of 40.8 pb<sup>−1</sup> collected in the years 1990, 1991 and 1992 corresponds to 1.09·10<sup>6</sup> hadronic and 0.98·10<sup>5</sup> leptonic Z decays observed. These data allow us to determine the electroweak parameters. From the cross sections we derive the properties of the Z boson:
M<sub>Z</sub>=91195 ± 9 MeVΓ<sub>Z</sub>=2494 ± 10 MeV
Γ<sub>had</sub>=1748 ± 10 MeVΓ<sub>ℓ</sub>=83.49 ± 0.46MeV
assuming lepton universality. We obtain an invisible width of Γ<sub>inv</sub>=496.5 ± 7.9 MeV which, in the Standard Model, corresponds to a number of light neutrino species of Nv=2.981 ± 0.050.
Using also the three leptonic forward-backward asymmetries and the average tau polarization, we determine the effective vector and axial-vector coupling constants of the neutral weak current to charged leptons to be:
g¯ℓv=−0.0378<sup>+0.0045</sup><sub>−0.0042</sub> g¯ℓA=−0.4998 ± 0.0014.
Within the framework of the Standard Model, and including our measurements of the Z→b¯b forward-backward asymmetry and partial decay width, we derive an effective electroweak mixing angle of sin<sup>2</sup>¯θ<sub>W</sub>=0.2326 ± 0.0012 . We obtain an estimate for the strong coupling constant, α<sub>S</sub>=0.142 ± 0.013 and for the top-quark mass,m<sub>t</sub> =158<sup>+32</sup><sub>−40</sub> ± 19(Higgs) GeV, where the second error arises due to the uncertainty in the Higgs-boson mass. |
| format |
Articulo Articulo |
| author |
Dova, María Teresa L3 Collaboration |
| author_facet |
Dova, María Teresa L3 Collaboration |
| author_sort |
Dova, María Teresa |
| title |
Measurement of cross sections and leptonic forward-backward asymmetries at the Z pole and determination of electroweak parameters |
| title_short |
Measurement of cross sections and leptonic forward-backward asymmetries at the Z pole and determination of electroweak parameters |
| title_full |
Measurement of cross sections and leptonic forward-backward asymmetries at the Z pole and determination of electroweak parameters |
| title_fullStr |
Measurement of cross sections and leptonic forward-backward asymmetries at the Z pole and determination of electroweak parameters |
| title_full_unstemmed |
Measurement of cross sections and leptonic forward-backward asymmetries at the Z pole and determination of electroweak parameters |
| title_sort |
measurement of cross sections and leptonic forward-backward asymmetries at the z pole and determination of electroweak parameters |
| publishDate |
1994 |
| url |
http://sedici.unlp.edu.ar/handle/10915/81046 |
| work_keys_str_mv |
AT dovamariateresa measurementofcrosssectionsandleptonicforwardbackwardasymmetriesatthezpoleanddeterminationofelectroweakparameters AT l3collaboration measurementofcrosssectionsandleptonicforwardbackwardasymmetriesatthezpoleanddeterminationofelectroweakparameters |
| bdutipo_str |
Repositorios |
| _version_ |
1764820488054374401 |