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(*) similar or equal to 0.15 +/- 0.02, although for this quantity a reliable continuum limit is still lacking.