Bochum 1998 – scientific programme
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HK: Hadronen und Kerne
HK 67: Structure of Baryons, Mesons IX, Theory
HK 67.3: Talk
Thursday, March 19, 1998, 15:00–15:15, H
Hexaquarks in a chiral constituent quark model — •S. Pepin1 and Fl. Stancu2 — 1Theoretical Physics Group, Department of Physics and Astronomy, University of Manchester, Manchester M13 9PL, United Kingdom — 2Université de Liège, Institut de Physique B.5, Sart Tilman, B-4000 Liège 1, Belgium
The theoretical study of baryon spectroscopy has recently been revitalized by the introduction of a chiral constituent quark model by Glozman and Riska [1] where the quarks interact via Goldstone boson-exchange (GBE) (pseudoscalar mesons), instead of the usual one gluon exchange (OGE). This makes the interaction flavour dependent. As a result, the ordering of positive and negative parity levels is correctly reproduced, at variance with OGE. Within the same model it is of great interest to study properties of multiquark systems, other than baryons. These predictions can confirm or reject the model. Here we present results for hexaquarks containing a heavy flavour. We find that the masses of the uuddsc and uuddsb systems are above the lowest threshold of decay into two baryons, by several hundreds of MeV. This situation is similar to NN and the H-particle [2]. It means that none of these systems can exist in a compact form. More elaborate calculations based on the resonating group method are required to prove their existence as molecular-type objects.
[1] L. Ya. Glozman and D. O. Riska, Physics Reports 268, 263 (1996).
[2] Fl. Stancu, S. Pepin and L. Ya. Glozman , Phys. Rev. C56, 2779 (1997); hep-ph/9707356, submitted to Phys. Rev. D.