Skip to main content
U.S. Department of Energy
Office of Scientific and Technical Information

A measurement of the (τ) polarization at the Z resonance with the DELPHI detector at LEP

Thesis/Dissertation ·
DOI:https://doi.org/10.2172/10116334· OSTI ID:10116334
 [1]
  1. Iowa State Univ., Ames, IA (United States)
The polarization of τ leptons produced in the reaction e+e- → τ+τ- near the peak of the Z° resonance has been measured using a sample of 24904 τ+τ- events, with an estimated background of 1.5%. We have selected 4562 τ → ev$$\bar{v}$$ 2218 τ → πv and 5133 τ→ ρv candidates. The mean value obtained is Pτ = -0.176 ± 0.029. This corresponds to a ratio of the neutral current vector to the axial-vector coupling constants of the τ lepton of gV/gAτ = 0.088 ± 0.014. This leads to a value of the electroweak mixing angle of sin2θW = 0.2280 ± 0.0036. This result is in good agreement with previous measurements of the weak mixing angle from the study of the Z° lineshape and the forward-backward asymmetries in the processes Z° → l+l- and Z° → q$$\bar{q}$$.
Research Organization:
Ames Lab., IA (United States)
Sponsoring Organization:
USDOE
DOE Contract Number:
W-7405-ENG-82
OSTI ID:
10116334
Report Number(s):
IS-T--1654; ON: DE94005557
Country of Publication:
United States
Language:
English