The gradient flow running coupling in SU(2) gauge theory with $N_f=8$ fundamental flavors

Abstract

We study the evolution of the coupling in SU(2) gauge field theory with $N_f=8$ fundamental fermion flavors on the lattice. This model is expected to have an infrared fixed point at high coupling. We use HEX-smeared Wilson-clover action, and measure the gradient flow running coupling with Dirichlet boundary conditions. Extrapolating our results to continuum, we find an infrared fixed point at $g^2=8.24(59{)}_{-1.64}^{+0.97}$, with statistical and systematic error estimates. We also measure the anomalous dimension of the quark mass operator, and find its value at the fixed point $\gamma \approx 0.15\pm 0.02$.

Comments: 24 pages, 11 figures, updated to match the published version