Pentaquark states in a chiral potential

Abstract

We discuss a possible interpretation for the pentaquark baryon ${\Theta }^{+}$ which has an exotic quantum number of strangeness $S=+1$. The role of the pion which modifies the structure of single-particle levels of quarks is examined. When the pion field is sufficiently strong, the ground state of five quarks for ${\Theta }^{+}$ acquires positive parity. If this is the case, an excited state may appear slightly above the ground state with negative parity.

Comments: 7 pages, 3 figures. Some errors in $s$ and $\bar{s}$ configurations are corrected