Scalar Densities and Baryon Mass Differences in Lattice QCD with Wilson Fermions

摘要

The normalization constant and the proton matrix elements of the scalar quark densities on a 10 cu x 20 lattice, at Beta = 6.0, in the quenched approximation and for 3 values of the Wilson parameter: K = 0.1515, 0.1530, 0.1545 were derived. The normalization constant agrees with a derived Ward identity. In terms of the usual D and F of the baryon octet mass differences, D/F = -0.4 + or -0.2, in agreement with the experimental value (D/F)exp = -0.3. It is seen that D/F decreases in absolute value for large quark mass, as suggested by the constituent quark model. Using a previous lattice determination of quark masses, M -Mp = 210 + or -60 MeV, to be compared with the measured value (M -Mp)exp = 380 MeV. The nucleon sigma term is 15 + or -4 MeV.