Z production cross-sections and lepton pair forward-backward asymmetries

ALEPH Collaboration (1994) Z production cross-sections and lepton pair forward-backward asymmetries. Zeitschrift für Physik C Particles and Fields, 62 (4). pp. 539-550. ISSN 0170-9739

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Abstract

Precise values of theZ resonance cross sections and lepton pair forward-backward asymmetries are measured from a sample of 1.3 millionZ decays into hadrons and charged leptons taken with the ALEPH detector at LEP. A silicon-tungsten luminosity calorimeter was installed in ALEPH in 1992, permitting the determination of the absolute luminosity to a systematic precision of 0.15% (experimental) and 0.25% (theoretical). This is combined with a better understanding of the hadronic event selection and an improved tau pair selection. Including the ALEPH results of the past three years one obtains σh0 =(41.60±0.16) nb, andRl=20.69±0.09. The corresponding number of light neutrino species isNv =2.983±0.034. The lepton pair forward-backward asymmetry is used to derive the ratio of vector to axial-vector couplings of leptons:gV2(MZ2)/gA2(MZ2)=0.0058 ±0.0011. An application of these results to constrain one model with extraZ bosons is presented.

Item Type:
Journal Article
Journal or Publication Title:
Zeitschrift für Physik C Particles and Fields
Uncontrolled Keywords:
/dk/atira/pure/subjectarea/asjc/3100/3101
Subjects:
?? PHYSICS AND ASTRONOMY (MISCELLANEOUS) ??
ID Code:
64093
Deposited By:
Deposited On:
08 May 2013 15:11
Refereed?:
Yes
Published?:
Published
Last Modified:
17 Sep 2023 01:21