Erlangen 2026 – wissenschaftliches Programm
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HK: Fachverband Physik der Hadronen und Kerne
HK 12: Hadron Structure and Spectroscopy IV
HK 12.1: Gruppenbericht
Dienstag, 17. März 2026, 16:15–16:45, PHIL A 401
Search for exotic states in ηc decays at BESIII — Tessa Bertelsmeier1, Jans Böing1, Anja Brüggemann1, Nils Hüsken2, Nikolai in der Wiesche1, Lois Kröger1, Hannah Neuwirth1, •Frederik Weidner1, and Alfons Khoukaz1 — 1Universität Münster, Germany — 2Johannes Gutenberg-Universität Mainz, Germany
The BESIII detector at the e+ e− collider BEPCII in Beijing, China, provides the world’s largest data sample of the charmonium J/ψ with more than 10 billion events collected from 2009 to 2019.
Starting from the radiative J/ψ decay into γ ηc, we analyse the reactions ηc → η′ h h (with h h = ππ, 2(ππ), KK, η η) to determine the corresponding branching ratios as well as the mass and width of the ηc. Moreover, these ηc decays provide the opportunity to investigate possible exotic content in h h intermediate states that lie in the mass region below 2 GeV/c2, where the lightest scalar glueball is predicted.
Our studies are based on a partial wave analysis approach that gives access to the partial decay widths of contributing resonances decaying into the h h subsystems. By coupling the considered channels multi-channel effects can be correctly incorporated. The extracted widths are directly comparable to theoretical predictions, which assume glueball admixtures carried by certain considered resonances.
This work is supported by the DFG under project numbers 443159800, 547123630 and GRK 2149/2 and by the Ministry for Culture and Science of the State North Rhine-Westphalia under funding code NW21-024-E.
Keywords: Glueball; Charmonium; Light Meson; Partial Wave Analysis; BESIII