Göttingen 2025 – wissenschaftliches Programm
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T: Fachverband Teilchenphysik
T 98: Electroweak Physics III (W/Z Production and Properties)
T 98.5: Vortrag
Freitag, 4. April 2025, 10:00–10:15, VG 2.103
Validating the Hadronic Recoil Calibration in the ATLAS low-⟨µ ⟩ W Mass Analysis — •Mathias Backes — Kirchhoff-Institut für Physik
The measurement of the mass of the W-boson is one of the fundamental tests of the Standard Model. ATLAS (2024) and CMS (2024) published measurements presenting results for the W-mass which are in agreement with the Standard Model. These measurements are in more than 5σ tension with the value obtained by the CDF collaboration (2022). In order to investigate this tension ATLAS is currently performing an additional measurement.
The W mass is most accurately measured using the leptonic decay channel W→ lνl with l ∈ (e, µ). The low-pileup dataset of ATLAS (taken in Run-2) is especially useful because a central aspect of this analysis is the precise estimation of the hadronic recoil to infer the energy and direction of the neutrino. Since the W mass cannot be measured directly it has to be inferred through comparisons with Monte Carlo simulations in a Profile Likelihood Fit. The success of such a fit strongly depends on the quality of the simulation. It is therefore necessary to explicitly calibrate the hadronic recoil estimation in the simulation to ensure it is modeled properly. The calibration can be validated by using Z-boson events, which can also be extracted from the low-pileup dataset.
Keywords: W mass; low-mu; ATLAS