Pentaquark baryons with Charm
نویسندگان
چکیده
We investigate the mass spectrum of pentaquark baryons with anticharm quark, in quenched lattice QCD with exact chiral symmetry. By chiral extrapolation to mπ = 135 MeV, we determine the masses of the lowest lying states of the antisextet (JΠ = 1/2+) and the triplet (JΠ = 1/2), in the isospin limit (mu = md). The masses of the antisextet are: 2977(109) MeV for the iso-singlet Θc([ud][ud]c̄); 3180(69) MeV for the iso-doublet {N c ([ud][ds]c̄), N 0 c ([ud][us]c̄)}; and 3650(95) MeV for the iso-triplet {Ξ 5c ([ds][ds]c̄),Ξ − 5c([ds][us]+c̄),Ξ 0 5c([us][us]c̄)}, all above the thresholds for strong decays. For the triplet, the mass of the iso-doublet {T c ([ud][ds]c̄), T 0 c ([ud][us]c̄)} is 2785(46) MeV, below the threshold for the strong decays. PACS numbers: 11.15.Ha, 11.30.Rd, 12.38.Gc
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