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Baryon spectroscopy

The spectrum of resonances is key to the understanding of the strong interaction. The Jülich-Bonn model including dynamically-coupled channels allows for a better understanding of experimental data.

Baryon spectroscopy

Baryon ResonancesEnergy dependence of the scattering matrix including resonance poles
Copyright: Deborah Rönchen

At medium energies, the spectrum of resonances encodes the key to understanding the strong force and the determination of the baryon spectrum is a long-range experimental and theoretical enterprise. Theory approaches to the strong force, ranging from Lattice QCD to unitarized Chiral Perturbation Theory and Quark models, can often not compare to the experimental data directly but have to rely on the resonance spectrum extracted from data. We have the paradoxical situation that presently high quality data are available from a variety of pion-, photon- and electron-induced reactions, with a very rich and complex structure, while at the same time the underlying dynamics is far from being understood. At IAS-4, we address the issue of excited baryonic states within a well-defined theoretical framework, the Jülich-Bonn dynamical coupled-channel model. The approach guarantees unitarity and analyticity and facilitates at the same time a comprehensive description of experimental data. The project aims at a refined insight into the dynamical nature of baryonic resonances with and without strangeness from a combined analysis of pion-, photon-, and electron-induced hadronic reactions. In the coming years, we will also develop and apply more rigorous statistical tools to quantify the significance of resonance signals.