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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.

Precise test of lepton flavour universality in W-boson decays into muons and electrons in pp collisions at s=13TeV 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

The ratio of branching ratios of the W boson to muons and electrons, RWμ/e=B(W→μν)/B(W→eν), has been measured using 140fb-1 of pp collision data at s=13 TeV collected with the ATLAS detector at the LHC, probing the universality of lepton couplings. The ratio is obtained from measurements of the tt¯ production cross-section in the ee, eμ and μμ dilepton final states. To reduce systematic uncertainties, it is normalised by the square root of the corresponding ratio RZμμ/ee for the Z boson measured in inclusive Z→ee and Z→μμ events. By using the precise value of RZμμ/ee determined from e+e- colliders, the ratio RWμ/e is determined to be (Formula presented.) The three uncertainties correspond to data statistics, experimental systematics and the external measurement of RZμμ/ee, giving a total uncertainty of 0.0045, and confirming the Standard Model assumption of lepton flavour universality in W-boson decays at the 0.5% level. © The Author(s) 2024.

Department/s

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

Publishing year

2024

Language

English

Publication/Series

European Physical Journal C

Volume

84

Issue

10

Document type

Journal article

Publisher

Springer Nature

Topic

  • Subatomic Physics

Keywords

  • Colliding beam accelerators
  • Linear accelerators
  • Positive ions
  • ATLAS detectors
  • Branching ratio
  • Dileptons
  • Final state
  • Lepton-flavor
  • Measurements of
  • Production cross section
  • Square-root
  • Systematic uncertainties
  • W bosons
  • Bosons

Status

Published

ISBN/ISSN/Other

  • ISSN: 1434-6044