Prediction of Narrow $J^{\pi }=1/2^{+}$, $3/2^{+}$, and $3/2^{-}$ states of ${\Theta }_{+}$ in a Quark model with Antisymmetrized Molecular Dynamics

Abstract

The exotic baryon ${\Theta }^{+}(uudd\bar{s})$ is studied with microscopic calculations in a quark model by using a method of antisymmetrized molecular dynamics. We predict that the lowest even state is $J^{\pi }=1/2^{+}(I=0)$ or $J^{\pi }=3/2^{+}(I=0)$, and the lowest odd state is $J^{\pi }=3/2^{-}(I=1)$. They nearly degenerate in the $uudd\bar{s}$ system. We discuss $K^{+}n$ decay widths and estimate them to be $\Gamma <7$ for the $J^{\pi }=\{1/2^{+},3/2^{+}\}$, and $\Gamma <1$ MeV for the $J^{\pi }=3/2^{-}$ state.

6 pages, 2 figures, submitted to Phys. Rev. D