Mainz 2022 – scientific programme
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HK: Fachverband Physik der Hadronen und Kerne
HK 10: Hadron Structure and Spectroscopy II
HK 10.1: Group Report
Monday, March 28, 2022, 14:00–14:30, HK-H9
Experimental Inputs to the Hadronic Light-by-Light Contribution to the Anomalous Magnetic Moment of the Muon from BESIII — •Christoph Florian Redmer, Achim Denig, Nick Effenberger, and Max Lellmann for the BESIII collaboration — Institut für Kernphysik, Johannes Gutenberg-Universität Mainz, Deutschland
Despite being one of the most precisely studied observables in particle physics, there remains a discrepancy of 4.2 σ between the average value of the most recent direct measurements and the prediction within the Standard Model of the anomalous magnetic moment of the muon aµ= (g−2)µ/2. The precision of the prediction is limited by the knowledge of the hadronic contributions, which cannot be determined perturbatively, but depend on input from experiments. One of these contributions is the hadronic Light-by-Light scattering, which depends on the knowledge of transition form factors of light pseudoscalar, scalar, axial, and tensor mesons as well as the coupling of multi-meson systems to two photons, which is accessible in e+e− collisions.
The BESIII experiment, operated at the BEPCII accelerator in Beijing, China, has collected the world’s largest data sets of e+e− collisions in the τ-charm region between 2 GeV and 5 GeV. The data are ideally suited to measure the momentum dependence of transition form factors at space-like momentum transfers of Q2≈ 1 GeV2, which is of special relevance in the context of aµ. In this presentation we discuss recent results, ongoing projects, and future prospects of the measurements at the BESIII experiment.