Variational Monte Carlo Study of Pentaquark States

Accurate numerical solution of the five-body Schrödinger equation is effected via variational Monte Carlo calculations. The spectrum is assumed to exhibit a narrow resonance with strangeness S=+1. A fully antisymmetrized and pair-correlated five-quark wave function is obtained for the assumed nonrelativistic Hamiltonian, which has spin, isospin, and color dependent pair interactions and many-body confining terms, which are fixed by the nonexotic spectra. Gauge field dynamics are modeled via flux-tube exchange factors. The energy determined for the ground states with J^π=1/2^-   (1/2⁺) is 2.22 (2.50) GeV. A lower energy negative parity state is consistent with recent lattice results. The short-range structure of the state is analyzed via its diquark content.