Bonn 2020 – wissenschaftliches Programm
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HK 13.1: Gruppenbericht
Dienstag, 31. März 2020, 17:00–17:30, J-HS A
Investigating the scalar meson sector with BESIII — •Nils Hüsken, Johannes Bloms, Anja Brüggemann, Alfons Khoukaz, Sascha Lennartz, and Frederik Weidner — Westfälische Wilhelms-Universität Münster, Germany
The scalar meson sector has long been subject of intense speculation. Lattice QCD calculations predict the lightest glueball to share its quantum numbers with the scalar mesons. From various experiments, five scalars with a mass below 2 GeV/c2 have been established, the f0(500), f0(980), f0(1370), f0(1500) and f0(1710). While it is clear that at least one of these states is supernumerary with respect to naive quark model expectations, there is no consensus on the nature of these scalar mesons yet. With the BESIII experiment, scalar mesons can be studied in different production and decay mechanisms. Using the world-record 1010 J/ψ mesons directly produced in e+e− annihilation with BESIII, scalar mesons can be studied both in direct decays of the J/ψ, for example in J/ψ→φ K K, as well as in ηc decays like ηc→η′KK. While the former channel gives access to scalar states with a strong ss component, ηc decays involving scalar resonances might potentially allow to study gg−qq mixing. In addition, the BESIII high statistics datasets at center-of-mass energies between 3.7 GeV and 4.6 GeV dedicated to the search for new, heavy resonances in the charmonium region are used to explore potential couplings of the XYZ states to the light (scalar) meson sector. The current status of these analyses being performed in the Münster BESIII group will be discussed. This project has received funding from the DFG (FOR2359 and GRK2149).