Anomalous decay and scattering processes of the eta meson

• Published in: arXiv.org
• Main Authors: Kubis, Bastian, Plenter, Judith
• Format: Paper Journal Article
• Language: English
• Published: Ithaca Cornell University Library, arXiv.org 26.06.2015
• Subjects: Decay; Eta-mesons; Form factors; Light scattering; Magnetic moments; Physics - High Energy Physics - Experiment; Physics - High Energy Physics - Phenomenology; Physics - Nuclear Experiment; Physics - Nuclear Theory; Tensors
• ISSN: 2331-8422
• DOI: 10.48550/arxiv.1504.02588

We amend a recent dispersive analysis of the anomalous \(\eta\) decay process \(\eta\to\pi^+\pi^-\gamma\) by the effects of the \(a_2\) tensor meson, the lowest-lying resonance that can contribute in the \(\pi\eta\) system. While the net effects on the measured decay spectrum are small, they may be more pronounced for the analogous \(\eta'\) decay. There are nonnegligible consequences for the \(\eta\) transition form factor, which is an important quantity for the hadronic light-by-light scattering contribution to the muon's anomalous magnetic moment. We predict total and differential cross sections, as well as a marked forward-backward asymmetry, for the crossed process \(\gamma\pi^-\to\pi^-\eta\) that could be measured in Primakoff reactions in the future.