Eur. Phys. J. A 12, 447-452 (2001)

Hypercentral constituent quark model and isospin dependence

M.M. Giannini, E. Santopinto and A. Vassallo

Dipartimento di Fisica dell'Università di Genova, I.N.F.N., Sezione di Genova, via Dodecaneso 33, 16146 Genova, Italy

giannini@genova.infn.it

(Received: 3 November 2001 Communicated by V.V. Anisovich )

Abstract
The constituent quark model based on a hypercentral approach takes into account three-body force effects and standard two-body potential contributions. The quark potential contains a hypercentral interaction, to which a hyperfine term is added. While the hypercentral potential supplies good values for the centroid energies of the resonance multiplets and a realistic set of quark wave functions, the hyperfine splittings are sometimes not sufficient to account for the observed masses. In this work we have introduced an improved form of the hyperfine interaction and an isospin-dependent quark potential. The resulting description of the baryon spectrum is very good, also for the Roper resonance, specially thanks to the flavour-dependent interaction.

PACS
12.39.Jh - Nonrelativistic quark model.
12.39.Pn - Potential models.
14.20.Gk - Baryon resonances with S=0 .

© Società Italiana di Fisica, Springer-Verlag 2001