Four-loop strong coupling beta-function in the Standard Model

In this letter we present our results for the four-loop beta-function of the strong coupling in the Standard Model of fundamental interactions. The expression is obtained from gluon self-energy diagrams in the background field gauge without application of special infra-red rearrangement tricks. We take top-Yukawa and self-Higgs interactions into account, but neglect electroweak gauge couplings. Ambiguities due to γ5 treatment are discussed and a particular “reading” prescription for odd Dirac traces is advocated.