Infrared fixed point in the massless twelve-flavor SU(3) gauge-fermion system

We present strong numerical evidence for the existence of an infrared fixed point in the renormalization group flow of the SU(3) gauge-fermion system with twelve massless fermions in the fundamental representation. Our numerical simulations using nHYP-smeared staggered fermions with Pauli-Villars improvement do not exhibit any first-order bulk phase transition in the investigated parameter region. We utilize an infinite volume renormalization scheme based on the gradient flow transformation to determine the renormalization group β function. We identify an infrared fixed point at g²GF=6.60(62) in the GF scheme and calculate the leading irrelevant critical exponent γg^=0.199(32). Our prediction for γg^ is consistent with available literature at the 1-2σ level.