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Measurement of electroweak parameters fromZ decays into fermion pairs
- Source :
- Zeitschrift für Physik C Particles and Fields; September 1990, Vol. 48 Issue: 3 p365-391, 27p
- Publication Year :
- 1990
-
Abstract
- We report on the properties of theZ resonance from 62 500Z decays into fermion pairs collected with the ALEPH detector at LEP, the Large Electron-Positron storage ring at CERN. We findM<subscript>Z</subscript>=(91.193±0.016<subscript>exp</subscript>±0.030<subscript>LEP</subscript>) GeV, G<subscript>Z</subscript>=(2497±31) MeV, s<subscript>had</subscript><superscript>0</superscript>=(41.86±0.66)nb, and for the partial widths G<subscript>inv</subscript>=(489±24) MeV, G<subscript>had</subscript>(1754±27) MeV, G<subscript>ee</subscript>=(85.0±1.6)MeV, G<subscript>µµ</subscript>=(80.0±2.5) MeV, and G<subscript>tt</subscript>=(81.3±2.5) MeV, all in good agreement with the Standard Model. Assuming lepton universality and using a lepton sample without distinction of the final state we measure G<subscript>u</subscript>=(84.3±1.3) MeV. The forward-backward asymmetry in leptonic decays is used to determine the vector and axial-vector weak coupling constants of leptors,g<subscript>v</subscript><superscript>2</superscript>(M<subscript>Z</subscript><superscript>2</superscript>)=(0.12±0.12)×10<superscript>-2</superscript> andg<subscript>A</subscript><superscript>2</superscript>(M<subscript>Z</subscript><superscript>2</superscript>)=0.2528±0.0040. The number of light neutrino species isN<subscript>?</subscript>=2.91±0.13; the electroweak mixing angle is sin<superscript>2</superscript>?<subscript>W</subscript>(M<subscript>Z</subscript><superscript>2</superscript>)=0.2291±0.0040.
Details
- Language :
- English
- ISSN :
- 01709739 and 14315858
- Volume :
- 48
- Issue :
- 3
- Database :
- Supplemental Index
- Journal :
- Zeitschrift für Physik C Particles and Fields
- Publication Type :
- Periodical
- Accession number :
- ejs15750023
- Full Text :
- https://doi.org/10.1007/BF01572019