Jun 22 – 27, 2023
Auditorium Maximum
Europe/Warsaw timezone

The BGOOD experiment at ELSA - exotic structures in the light quark sector?

Jun 24, 2023, 9:00 AM
Medium lecture hall (A and B) (Auditorium Maximum)

Medium lecture hall (A and B)

Auditorium Maximum

Invited Plenary session


Thomas Jude (University of 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 in meson photoproduction, where access to a low momentum exchange and forward meson production angles is crucial to study such phenomena. The BGOOD photoproduction experiment is uniquely designed to explore this kinematic region, being comprised of a central calorimeter complemented by a magnetic spectrometer in forward directions.

Highlighted results indicate a peak-like structure in the $\gamma n \rightarrow K^0\Sigma^0$ cross section at a centre-of-mass energy of 2 GeV consistent with a meson-baryon interaction model which predicted the charmed $P_C$ states. The same $K^*\Sigma$ molecular nature of this proposed $N^*(2030)$ is also supported in a measurement of $\gamma p\rightarrow K^+\Lambda(1405)\rightarrow K^+\pi^0\Sigma^0$, 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 $d^*(2380)$. Data will be presented which support 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.

Collaboration BGOOD

Primary author

Thomas Jude (University of Bonn)

Presentation materials

Peer reviewing