Pentaquark components in low-lying baryon resonances

Abstract

We study pentaquark states of both light $q^4\bar{q}$ and hidden heavy $q^{3}Q\bar{Q}$ (q = u,d,s quark in SU(3) flavor symmetry; Q = c, b quark) systems with a general group theory approach in the constituent quark model, and the spectrum of light baryon resonances in the ansatz that the $l=1$ baryon states may consist of the $q^3$ as well as $q^4\bar{q}$ pentaquark component. The model is fitted to ground state baryons and light baryon resonances which are believed to be normal three-quark states. The work reveals that the $N(1535)1/2^{-}$ and $N(1520)3/2^{-}$ may consist of a large $q^4\bar{q}$ component while the $N(1895)1/2^{-}$ and $N(1875)3/2^{-}$ are respectively their partners, and the $N^{+}(1685)$ might be a $q^4\bar{q}$ state. By the way, a new set of color-spin-flavor-spatial wave function for $q^{3}Q\bar{Q}$ systems in the compact pentaquark picture are constructed systematically for studying hidden charm pentaquark states.

9 pages, 14 tables