On the gauge-invariant operator Amin2in Euclidean Yang-Mills theories

We review our recent work on the gauge-invariant non-local dimension-two operator Amin2, whose minimization is defined along the gauge orbit. Albeit non-local, the operator Amin2can be cast in local form through the introduction of an auxiliary Stueckelberg field. The whole procedure results into a local action which turns out to be renormalizable to all orders.