Mixing and decays of the antidecuplet in the context of approximate SU(3) symmetry

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We consider mixing of the antidecuplet with three Jᵖ=1/2+ octets (the ground-state octet, the octet containing N(1440), Λ(1600), Σ(1660) and Ξ(1690) and the octet containing N(1710), Λ(1800), Σ(1880) and Ξ(1950)) in the framework of approximate flavor SU(3) symmetry. We give general expressions for the partial decay widths of all members of the antidecuplet as functions of the two mixing angles. Identifying Nanti-10 with the N(1670) observed by the GRAAL experiment, we show that the considered mixing scenario can accommodate all present experimental and phenomenological information on the Θ+ and Nanti-10 decays: Θ+ could be as narrow as 1 MeV; the Nanti-10 -> N + ηdecay is sizable, while the Nanti-10 ->N + πdecay is suppressed and the Nanti-10 ->Λ+ K decay is possibly suppressed. Constraining the mixing angles by the Nanti-10 decays, we make definite predictions for the Σanti-10 decays. We point out that Σanti-10 with mass near 1770 MeV could be searched for in the available data on Kₛ p invariant mass spectrum, which already revealed the Θ+ peak. It is important to experimentally verify the decay properties of Σ(1770) because its mass and Jᵖ=1/2+ make it an attractive candidate for Σanti-10.