Probing the region of massless quarks in quenched lattice QCD using Wilson fermions Original Research Article

We study the spectrum of H(m) = γ5W(-m) withW(m) being the Wilson-Dirac operator on the lattice with bare mass equal to m. The background gauge fields are generated using the SU(3) Wilson action at β = 5.7 on an 83 x 16 lattice. We find evidence that the spectrum of H(m) is gapless for 1.02 < m < 2.0, implyring that the physical quark is massless in this whole region.