Scattering problem of the uudds̄ system in the standard nonrelativistic quark model of Isgur-Karl is solved for the first time, by treating the large five-body model space including the NK scattering channel accurately with the Gaussian expansion method and the Kohn-type coupled-channel variational method. The two-body interaction that reproduces observed properties of ordinary baryons and mesons is applied to the pentaquark system with no additional adjustable parameter. The resulting five-body wave function has the correct asymptotic form in its scattering-channel component and describes qq and qq̄ correlations properly. The NK scattering phase shift shows no resonance in the energy region of the reported pentaquark Θ +(1540), that is, at 0-500 MeV above the NK threshold (1.4-1.9 GeV in mass). Instead, the phase shift does show two resonances just above 500 MeV: a broad 12+ resonance with a width of Γ∼110MeV located at ∼520MeV (∼2.0GeV in mass) and a sharp 1/2- resonance with Γ=0.12MeV at 540 MeV. Properties of these states are discussed.
|ジャーナル||Physics Letters, Section B: Nuclear, Elementary Particle and High-Energy Physics|
|出版ステータス||出版済み - 2月 9 2006|
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