Backward running or absence of running from Creutz ratios

Abstract

We extract the running coupling based on Creutz ratios in SU(2) lattice gauge theory with two Dirac fermions in the adjoint representation. Depending on how the extrapolation to zero fermion mass is performed, either backward running or an absence of running is observed at strong bare coupling. This behavior is consistent with other findings which indicate that this theory has an infrared fixed point.

Comments: 12 pages, 3 figures; v2 fifth mass point added, three extrapolations now performed, conclusions softened