J^P=1⁺ ud[overline s][overline s] tetraquark

Using the color-magnetic interaction Hamiltonian with SU(3) flavor symmetry breaking, we perform a schematic study of the masses of the J^P=1⁺ tetraquarks in the antidecuplet representation. After diagonalizing the mass matrix, we find the ud[overline s][overline s] tetraquark could lie as low as about 1350 MeV. It decays into K⁺K⁰pi⁰, K⁺K⁺pi^-, K⁰K⁰pi⁺ via P-wave. The dual suppression from the not-so-big three-body phase space and P-wave decay barrier may render this exotic state rather narrow. Future experimental exclusion of this state will cast doubt on the validity of applying the simple color-magnetic Hamiltonian to the multiquark system.

©2006 The American Physical Society