Scheme-independent calculation of γ ψ ψ,IR for an SU(3) gauge theory SCHEME-INDEPENDENT CALCULATION of ... THOMAS A. RYTTOV and ROBERT SHROCK

We present a scheme-independent calculation of the infrared value of the anomalous dimension of the fermion bilinear, γψψ,IR in an SU(3) gauge theory as a function of the number of fermions, Nf, via a series expansion in powers of Δf, where Δf=(16.5-Nf), to order Δf4. We perform an extrapolation to obtain the first determination of the exact γψψ,IR from continuum field theory. The results are compared with calculations of the n-loop values of this anomalous dimension from series in powers of the coupling and from lattice measurements.