Göttingen 2025 – wissenschaftliches Programm

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T: Fachverband Teilchenphysik

T 11: Data, AI, Computing, Electronics I (Statistical Methods, Applications)

T 11.5: Vortrag

Montag, 31. März 2025, 17:45–18:00, VG 2.101

Impact and improvement of handling uncertainties regarding R(D) and R(D*) combining algorithms — •Stefanie Meinert, Ilias Tsaklidis, Florian Bernlochner, and Markus Prim — Physikalisches Institut der Rheinischen Friedrich-Wilhelms-Universität Bonn

Unexplained phenomena like the matter-antimatter asymmetry and neutrino masses motivate precise measurements of Standard Model (SM) parameters. Testing Lepton Flavor Universality (LFU), which predicts equal coupling of all lepton flavors to the W boson, offers a promising approach to uncover new physics. The analysis of R(D) and R(D^*) in semileptonic B decays is ideal due to its theoretical predictability and experimental accessibility.
HFLAV combined results from LHCb, BaBar, Belle, and Belle II to estimate R(D) and R(D^*), finding deviations of 1.6σ and 2.5σ from SM predictions. Their χ²-based Combination Code (CoCo), which accounts for statistical and systematic correlations, yields a significance of 3.31σ relative to the SM, indicating potential new physics.
These results rely on assumptions and approximations about systematic correlations, and inconsistent reporting of uncertainties challenges result combinations. Using HFLAV data, we explore the impact of systematic uncertainty variations and present a first average of R(D) and R(D^*) from three internal Belle II measurements via likelihood combinations, leveraging pyhf and SysVar, a Python-based package developed at the University of Bonn for consistent treatment of systematic uncertainties.

Keywords: pyhf; SysVar; Uncertainties; R(D); R(D*)