QCD Lambda Parameter from Gradient Flow

Abstract

Starting from the running coupling in the gradient flow scheme, the QCD Lambda parameter $\Lambda_{\,\overline{\!\rm MS\!}\;}$ is determined analytically with respect to the reference scale $w_0$ in the pure gauge theory. A key element is the gluon condensate, which, being invariant under RG transformations, establishes a formal relationship between $\Lambda_{\,\overline{\!\rm MS\!}\;}$ and $w_0$. Good agreement with numerical estimates is found.