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

Understand

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 $g^2=8.24(59)^{+0.97}_{-1.64}$, with statistical and systematic error estimates.