Constraints on widths of mixed pentaquark multiplets
We determine constraints on the partial widths of mixed pentaquark multiplets in the framework of heavy baryon chiral perturbation theory (HB$χ$PT). The partial widths satisfy a GMO-type relation at leading order in HB$χ$PT, for arbitrary mixing. The widths of N(1440), N(1710), and $Θ(1540)$ are not consistent with ideal mixing, $θ_{N} = 35.3^{\circ}$, but are consistent with $θ_{N} \lesssim 25^{\circ}$. Furthermore, there are parameter values in HB$χ$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.
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