Scalar Mesons in Lattice QCD

We explore whether “f${}_0$(600) or $\sigma$” exists as a pole in QCD, by a full lattice QCD simulation on the $8^3\times 16$ lattice using the plaquette action and Wilson fermions. It is shown that a low-mass $\sigma$ pole exists owing to the disconnected diagram of the meson propagator. A discussion is given on the physical content of the $\sigma$.