SMuK 2023 – wissenschaftliches Programm

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HK: Fachverband Physik der Hadronen und Kerne

HK 39: Hadron Structure and Spectroscopy IV

HK 39.1: Gruppenbericht

Mittwoch, 22. März 2023, 15:45–16:15, SCH/A316

The BGOOD experiment at ELSA - exotic structures in the light quark sector? — •Thomas Jude for the BGOOD collaboration — Physikalisches Institut, Universität Bonn

The discoveries of the pentaquark states and XYZ mesons in the charmed quark sector initiated a new epoch in hadron physics, where the existence of exotic multi-quark states beyond the conventional three and two quark systems has been unambiguously realised. Similar structure may be evidenced in the light, uds sector, where access to a low momentum exchange and forward meson production region is crucial to study such phenomena. The BGOOD photoproduction experiment is uniquely designed to explore this kinematic region; it is comprised of a central calorimeter complemented by a magnetic spectrometer in forward directions.

Highlighted results include the indication of a peak-like structure in the γ n → K⁰Σ⁰ cross section consistent with a meson-baryon interaction model which predicted the charmed P_C states. The same K^*Σ molecular nature of this proposed N^*(2030) is also supported in our measurement of γ p→ K⁺Λ(1405)→ K⁺π⁰Σ⁰, where it is predicted to drive a triangle singularity mechanism. In the non-strange sector, coherent meson photoproduction off the deuteron enables access to proposed dibaryon states, including the recently discovered d^*(2380). Results will be presented which support recent experimental claims of higher mass isoscalar and isovector dibaryons.

Supported by DFG projects 388979758/405882627 and the European Union’s Horizon 2020 programme, grant 824093.