| 摘 要： | We confirm our previous prediction of a d* state with I(JP) = 0(3+) Phys. Rev. C 60, 045203(1999)] and report for the first time based on a microscopic calculation that d* has about 2/3 hidden color(CC)configurations and thus is a hexaquark-dominated exotic state. By performing a more elaborate dynamical coupledchannels investigation of the △△-CC system within the framework of the resonating group method(RGM) in a chiral quark model, we find that the d* state has a mass of about 2.38–2.42 Ge V, a root-mean-square radius(RMS) of0.76–0.88 fm, and a CC fraction of 66%–68%. The last may cause a rather narrow width for the d* which, together with the quantum numbers and our calculated mass, is consistent with the newly observed resonance-like structure(M ≈2380 Me V, Γ≈70 Me V) in double-pionic fusion reactions reported by the WASA-at-COSY Collaboration.
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