Chiral properties of the Wilson fermion in SU(2) lattice gauge theory

The chiral properties of the Wilson fermion are examined with Monte Carlo techniques within the SU(2) lattice gauge theory in the quenched approximation. The results found are rather disturbing: over the range β =4/g₀² = 2.2-2.6, the chiral order parameter decreases slower than the scaling prediction, over after subtraction of the weak-coupling contribution, and the coupling of the flavor singlet meson to the topological charge is at least an order of magnitude too small to explain the π-η and η-η' mass splittings.