Spin-3/2 pentaquark resonance signature in lattice QCD

The possible discovery of the Θ⁺ pentaquark has motivated a number of studies of its nature using lattice QCD. While all the analyses thus far have focused on spin-1/2 states, here we report the results of the first exploratory study in quenched lattice QCD of pentaquarks with spin 3/2. For the spin-3/2 interpolating field we use a product of the standard N and K^* operators. We do not find any evidence for the standard lattice resonance signature of attraction (i.e., binding at quark masses near the physical regime) in the J^P=3/2^- channel. Some evidence of binding is inferred in the isoscalar 3/2⁺ channel at several quark masses, in accord with the standard lattice resonance signature. This suggests that this is a good candidate for the further study of pentaquarks on the lattice.