Penta-quark anti-decuplet in anisotropic lattice QCD

The penta-quark(5Q) Theta(+)(1540) is studied in anisotropic lattice QCD with renormalized anisotropy a(s)/a(t) = 4 for a high-precision measurement. Both the positive and the negative parity 5Q baryons are studied using a non-NK type interpolating field with I = 0 and J = 1/2. After the chiral extrapolation, the lowest positive parity state is found at mTheta similar or equal to 2.25 GeV, which is too heavy to be identified with Theta(+)(1540). In the negative parity channel, the lowest energy state is found at mTheta similar or equal to 1.75 GeV. Although it is rather close to the empirical value, it is considered to be an NK scattering state rather than a localized resonance state.