Details

Autor(en) / Beteiligte

• Klempt, Eberhard
• Richard, Jean-Marc

Titel

Baryon spectroscopy

Ist Teil von

• Reviews of modern physics, 2010-04, Vol.82 (2), p.1095-1153

Ort / Verlag

United States: American Physical Society

Erscheinungsjahr

2010

Link zum Volltext

Quelle

American Physical Society [PROLA]

Beschreibungen/Notizen

• About 120 baryons and baryon resonances are known, from the abundant nucleon with $u$ and $d$ light-quark constituents up to the recently discovered $\Omega_b^-=bss$, and the $\Xi_b^-=bsd$ which contains one quark of each generation. In spite of this impressively large number of states, the underlying mechanisms leading to the excitation spectrum are not yet understood. Heavy-quark baryons suffer from a lack of known spin-parities. In the light-quark sector, quark-model calculations have met with considerable success in explaining the low-mass excitations spectrum but some important aspects like the mass degeneracy of positive-parity and negative-parity baryon excitations are not yet satisfactorily understood. At high masses, above 1.8 GeV, quark models predict a very high density of resonances per mass interval which is not observed. In this review, issues are identified discriminating between different views of the resonance spectrum; prospects are discussed how open questions in baryon spectroscopy may find answers from photo- and electro-production experiments which are presently carried out in various laboratories.