Speaker
Volker Crede
(Florida State University)
Description
The spectrum of excited hadrons - mesons and baryons - serves as an excellent probe of Quantum Chromodynamics (QCD), the fundamental theory of the strong interaction. The strong coupling however makes QCD very challenging. It confines quarks and breaks chiral symmetry, thus providing us with the world of light hadrons. Highly-excited hadronic states are sensitive to the details of quark confinement, which is only poorly understood within QCD. This is the regime of non-perturbative QCD and it is one of the key issues in hadronic physics to identify the corresponding internal degrees of freedom that give rise to excited hadrons and how these relate to strong coupling QCD. The quark model suggests mesons are made of a constituent quark and an anti-quark and baryons consist of three such quarks. The current experimental efforts toward mapping the baryon spectrum at several facilities around the world involve the challenging study of meson production off the nucleon using electromagnetic probes in so-called complete experiments utilizing beam and target polarization. Other questions in hadron spectroscopy remain open: What is the role of glue? Resonances with large gluonic components are predicted as bound states by QCD. The lightest hybrid mesons with exotic quantum numbers are estimated to have masses in the range from 1 to 2 GeV/
Author
Volker Crede
(Florida State University)
