Dortmund 2021 – wissenschaftliches Programm
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T: Fachverband Teilchenphysik
T 53: Electroweak Interactions I
T 53.1: Vortrag
Mittwoch, 17. März 2021, 16:00–16:15, Tc
Measuring lepton universality, mass and width of the W-boson with the ATLAS detector — Lennart Adam2, Nassim Ainouz1, Philip Bechtle1, Klaus Desch1, Oleh Kivernyk1, Jakub Kremer2, •Philipp König1, and Matthias Schott2 — 1Rheinische-Friedrich-Wilhelms-Universität Bonn — 2Johannes Gutenberg-Universität Mainz
In 2017, the ATLAS collaboration measured the W-boson mass using pp-collision data taken at √s=7 TeV in 2010, resulting in the most precise single measurement with a precision of 19 MeV. We present a revised analysis of the same dataset, improving the fit methods and including a measurement of the width of the W-boson. A precise measurement of these quantities and a test of lepton universality in the decay of the W-boson represent an excellent precision test of the Standard Model (SM).
A deviation of the branching fraction BR(W→τν) from the SM prediction would be an indicator for new physics coupling predominantly to heavier particles. Experimentally, it is preferable to measure the ratio of the branching ratios of the tau lepton decay into light leptons compared to the direct W decay into light leptons. However, it implies that numerator and denominator only differ in kinematic distributions from which the result is extracted in a fit. The most important observables for the fitting procedure will be discussed as well as possibilities increasing the sensitivity of the measurement. Finally, the expected sensitivity will be compared to previous measurements by other experiments.