Physical Nucleon Properties from Lattice QCD

We investigate various resummations of the chiral expansion and fit to the extremely accurate lattice QCD data for the mass of the nucleon recently obtained by the CP-PACS group. Using a variety of finite-range regulators, we demonstrate a remarkably robust chiral extrapolation of the nucleon mass. The systematic error associated with the chiral extrapolation alone is estimated to be less than 1%.

Figure 1

Fits to lattice data for various ultraviolet regulators. The sharp cutoff, monopole, dipole, and Gaussian cases are depicted by solid lines, indistinguishable on this plot. The dimensional regularized forms are illustrated by the dash-dotted curves, with the correct branch point corresponding to the higher curve. Lattice data are from Ref. 2.

Figure 2

Error analysis for the extraction of the nucleon mass using a dipole regulator. The shaded region corresponds to the region allowed within the present statistical errors.