Pentaquarks in Chiral Soliton Models; notes and discussion

Abstract

The spectra of pentaquarks, some of them being observed recently, are discussed within topological soliton model and compared with simplified quark picture. Results obtained within chiral soliton model depend to some extent on the quantization scheme: rigid rotator, soft rotator, or bound state model. The similarity of spectra of baryon resonances obtained within quark model and chiral soliton model is pointed out, although certain differences take place as well, which require careful interpretation. In particular, considerable variation of the strange antiquark mass in different SU(3) multiplets of pentaquarks is required to fit their spectra obtained from chiral solitons. Certain difference of masses of "good" and "bad" diquarks is required as well, in qualitative agreement with previously made estimates. The partners of exotic states with different values of spin which belong to higher SU(3) multiplets, have the energy considerably higher than states with lowest spin, and this could be a point where the difference from simple quark models is striking. The antiflavor excitation energies for multibaryons are estimated as well, and binding energies of $Θ$-hypernuclei and anticharm (antibeauty) hypernuclei are presented for several baryon numbers. Some deficiencies in the argumentation against validity of the chiral soliton approach and/or SU(3) quantization models, existing in the literature, are pointed out.