Kaon-soliton bound state approach to the pentaquark states

We show that in hidden local symmetry theory with the vector manifestation (VM), a $K^{+}$ can be bound to skyrmion to give an exotic baryon that has the quantum numbers of the ${\Theta }^{+}$ pentaquark with spin $1/2$ and even parity which is consistent with large $N_c$ counting. The vector meson $K^{*}$ subject to the VM in the chiral limit plays an essential role in inducing the binding.

Figure 1

Schematic illustration of the WZ-like terms due to vector mesons in the Lagrangian (7). The baryon number density is given by the three pion lines stemming from the shaded area, i.e., the soliton. In the limit of infinitely heavy meson masses, an exact cancellation takes place among the three terms.

Figure 2

The eigenenergies of $S=\pm 1$, ${\lambda }^P={\frac{1}{2}}^{\pm },{\frac{3}{2}}^{-}$ states obtained for various $a$ values. The width of the resonance in the $K^{+}$-skyrmion channel is given by the error bar.