Hadron masses in lattice QCD with internal fermion loops

Abstract

Results are presented for light hadron and quark masses in lattice quantum chromodynamics with fermion vacuum polarization effects. A lattice of size 10×10×10×30 is used with a gauge coupling g 2=1.111 and n f=3. Previous qualitative results obtained with Wilson fermions on a smaller lattice at the same value of the coupling constant are confirmed and extended. The values for the hadron masses in units of the lattice spacing are significantly affected by the inclusion of three light fermion flavors, but the change can be reabsorbed to a large degree in a rescaling of the cutoff. For small quark mass the physical hadron mass estimates are comparable to the results with no loops and in reasonable agreement with phenomenology. Fermion loop effects on the other hand tend to change the dependence of the physical hadron masses on the quark mass, which in turn affects the estimates for the quark masses. These are found to be smaller than had previously been estimated. By considering heavy valence and light sea quarks, light quark masses are directly compared to the heavier quark masses.