Running coupling in SU(2) gauge theory with two adjoint fermions

Abstract

We study SU(2) gauge theory with two Dirac fermions in the adjoint representation of the gauge group on the lattice. Using clover improved Wilson fermion action with hypercubic truncated stout smearing we perform simulations at larger coupling than earlier. We measure the evolution of the coupling constant using the step scaling method with Schr\"odinger functional and study the remaining discretization effects. At weak coupling we observe significant discretization effects, which make it difficult to obtain a fully controlled continuum limit. Nevertheless, the data remains consistent with the existence of a fixed point in the interval $2.2\lesssim g^{\ast 2}\lesssim 3$. We also measure the anomalous dimension and find its value at the fixed point is $\gamma^\ast\simeq 0.2\pm 0.03$.