This article is cited in 5 papers

FIELDS, PARTICLES, AND NUCLEI

Baryon resonances in the mean field approach and a simple explanation of the $\Theta^+$ pentaquark

D. I. Diakonov

Petersburg Nuclear Physics Institute RAS

Abstract: We suggest to classify baryon resonances as single-quark states in a mean field, and/or as its collective excitations. Identifying the Roper resonance $N(1440,{\textstyle{\frac12}}^+)$, the nucleon resonance $N(1535,{\textstyle{\frac12}}^-)$, and the singlet hyperon $\Lambda(1405,{\textstyle{\frac12}}^-)$ as single-quark excitations, we find that there must be an exotic $S=+1$ baryon resonance $\Theta^+\,$ (the “pentaquark”) with a mass about $1440+1535-1405=1570$ MeV and spin-parity ${\textstyle{\frac12}}^+$. We argue that $\Theta^+\,$ is an analog of the Gamov–Teller excitation long known in nuclear physics.

PACS: 12.39.Ki, 14.20.Dh, 14.20.Jn

Received: 10.08.2009

Language: English

 English version: Journal of Experimental and Theoretical Physics Letters, 2009, 90:6, 407–411

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