Measurement of the τ Lepton Polarization in Z Boson Decays in Proton-Proton Collisions at √s = 13 TeV
Journal of High Energy Physics 2024
Kārlis Dreimanis, Antra Gaile, Guntis Pikurs, Andris Potrebko, Markus Seidel, Viesturs Veckalns, CMS Collaboration

The polarization of τ leptons is measured using leptonic and hadronic τ lepton decays in Z → τ+ τ− events in proton-proton collisions at (Formula presented.) 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 Pτ(Z) = −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 = − Pτ(Z) 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 θWeff , independently of the Z boson production mechanism. The obtained value sin2 θWeff = 0.2319 ± 0.0008(stat) ± 0.0018(syst) = 0.2319 ± 0.0019 is in good agreement with measurements at e+ e− colliders. [Figure not available: see fulltext.].


Keywords
Hadron-Hadron Scattering | Tau Physics
DOI
10.1007/JHEP01(2024)101
Hyperlink
https://link.springer.com/article/10.1007/JHEP01(2024)101

The CMS Collaboration, A.Hayrapetyan, K.Dreimanis, A.Gaile, G.Pikurs, A.Potrebko, M.Seidel, V.Veckalns ... [et al.]. Measurement of the τ Lepton Polarization in Z Boson Decays in Proton-Proton Collisions at √s = 13 TeV. Journal of High Energy Physics, 2024, Vol. 2024, No. 1, Article number 101. e-ISSN 1029-8479. Pieejams: doi:10.1007/JHEP01(2024)101

Publication language
English (en)
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