Constraints on widths of mixed pentaquark multiplets

Abstract

We determine constraints on the partial widths of mixed pentaquark multiplets in the framework of heavy baryon chiral perturbation theory (HB$\chi$PT). The partial widths satisfy a GMO-type relation at leading order in HB$\chi$PT, for arbitrary mixing. The widths of N(1440), N(1710), and $\Theta (1540)$ are not consistent with ideal mixing, ${\theta }_N=35.3^{\circ }$, but are consistent with ${\theta }_N\lesssim 25^{\circ }$. Furthermore, there are parameter values in HB$\chi$PT that produce such a mixing angle while allowing the identification of the mass spectrum above. As an alternative to non-ideal mixing, we also suggest reasons for giving up on N(1440) as a pure pentaquark state.

Comments: 12 pages, 4 figures