Measurement of the τ lepton polarization in Z boson decays in proton-proton collisions at √𝑠 = 13 TeV
Name
13130_2024_Article_22610.pdf
Size
1.68 MB
Format
Adobe PDF
Checksum (MD5)
2131ed43ff07e14abb47add01b3e0feb
Author(s)
Hayrapetyan, A.
Tumasyan, A.
Adam, W.
Andrejkovic, J. W.
Bergauer, T.
Chatterjee, S.
Damanakis, K.
Dragicevic, M.
Escalante Del Valle, A.
Hussain, P. S.
Date Issued
January 19, 2024
Publisher
Springer Berlin Heidelberg
Citation
Journal of High Energy Physics. 2024 Jan 19;2024(1):101
Version
Final published version
Abstract
The polarization of τ leptons is measured using leptonic and hadronic τ lepton decays in Z → τ+τ− events in proton-proton collisions at
s
$$ \sqrt{s} $$
= 13 TeV recorded by CMS at the CERN LHC with an integrated luminosity of 36.3 fb−1. The measured τ− lepton polarization at the Z boson mass pole is
P
τ
Z
$$ {\mathcal{P}}_{\tau}\left(\textrm{Z}\right) $$
= −0.144 ± 0.006 (stat) ± 0.014 (syst) = −0.144 ± 0.015, in good agreement with the measurement of the τ lepton asymmetry parameter of Aτ = 0.1439 ± 0.0043 =
−
P
τ
Z
$$ -{\mathcal{P}}_{\tau}\left(\textrm{Z}\right) $$
at LEP. The τ lepton polarization depends on the ratio of the vector to axial-vector couplings of the τ leptons in the neutral current expression, and thus on the effective weak mixing angle sin2
θ
W
eff
$$ {\theta}_{\textrm{W}}^{\textrm{eff}} $$
, independently of the Z boson production mechanism. The obtained value sin2
θ
W
eff
$$ {\theta}_{\textrm{W}}^{\textrm{eff}} $$
= 0.2319 ± 0.0008(stat) ± 0.0018(syst) = 0.2319 ± 0.0019 is in good agreement with measurements at e+e− colliders.
MIT Department
Massachusetts Institute of Technology. Department of Physics
Terms of Use
Creative Commons Attribution
Persistent DSpace Link
DOI of Published Version
https://doi.org/10.1007/JHEP01(2024)101
