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Sten is a caucasian male with cropped red hair and beard.

Sten Åstrand

Doctoral student

Sten is a caucasian male with cropped red hair and beard.

Studies of the Energy Dependence of Diboson Polarization Fractions and the Radiation-Amplitude-Zero Effect in WZ Production with the ATLAS Detector

Author

  • G. Aad
  • T.P.A. Åkesson
  • K.S.V. Astrand
  • C. Doglioni
  • P.A. Ekman
  • V. Hedberg
  • H. Herde
  • B. Konya
  • E. Lytken
  • R. Poettgen
  • N.D. Simpson
  • O. Smirnova
  • E.J. Wallin
  • L. Zwalinski
Show all

Summary, in English

This Letter presents the first study of the energy dependence of diboson polarization fractions in WZ→ℓνℓ^{'}ℓ^{'}(ℓ,ℓ^{'}=e,μ) production. The dataset used corresponds to an integrated luminosity of 140 fb^{-1} of proton-proton collisions at a center-of-mass energy of 13 TeV recorded by the ATLAS detector. Two fiducial regions with an enhanced presence of events featuring two longitudinally polarized bosons are defined. A nonzero fraction of events with two longitudinally polarized bosons is measured with an observed significance of 5.3 standard deviations in the region with 100200 GeV, where p_{T}^{Z} is the transverse momentum of the Z boson. This Letter also reports the first study of the radiation-amplitude-zero effect. Events with two transversely polarized bosons are analyzed for the ΔY(ℓ_{W}Z) and ΔY(WZ) distributions defined respectively as the rapidity difference between the lepton from the W boson decay and the Z boson and the rapidity difference between the W boson and the Z boson. Significant suppression of events near zero is observed in both distributions. Unfolded ΔY(ℓ_{W}Z) and ΔY(WZ) distributions are also measured and compared to theoretical predictions.

Department/s

  • Particle and nuclear physics
  • eSSENCE: The e-Science Collaboration
  • Department of Physics

Publishing year

2024

Language

English

Publication/Series

Physical Review Letters

Volume

133

Issue

10

Document type

Journal article

Publisher

American Physical Society

Topic

  • Subatomic Physics

Keywords

  • article
  • controlled study
  • drug therapy
  • energy
  • human
  • polarization

Status

Published

ISBN/ISSN/Other

  • ISSN: 1079-7114