L
J
Last name: LEROY
First name: J. P.
We trace here instantons through the analysis of pure Yang-Mills gluon Green functions in the Landau gauge for a window of IR momenta (0.4
The next-to-leading-order (NLO) term in the operator product expansion (OPE) of the quark propagator vector part Zψ and the vertex function g1 of the vector current in the Landau gauge should be dominated by the same ⟨A2⟩ condensate as in the gluon propagator. On the other hand, the perturbative part has been calculated to a very high precision...
We give a more transparent understanding of the vacuum expectation value of the renormalized local operator A2 by relating it to the gluon propagator integrated over the momentum. The quadratically divergent perturbative contribution is subtracted and the remainder, dominantly due to the O(1/p2) correction to the perturbative propagator at...
We present a study of αMOM(p) at small p computed from the lattice in the quenched approximation (nf = 0). It shows a dramatic ∝ p4 law which can be understood within an instanton liquid model. In this framework the prefactor gives a direct measure of the instanton density in thermalised configurations. A preliminary result for this density is...
We argue that the ⟨A2OPE⟩ condensate found in the Landau gauge on lattices, when an operator product expansion of Green's functions is performed, might be explained by instantons. We use cooling to estimate the instanton contribution and extrapolate back the result to the thermalized configuration. The resulting ⟨A2inst⟩ is similar to ⟨A2OPE⟩.
Gluon two- and three-point Green Functions computed in Landau gauge from the lattice show the existence of power corrections to the purely perturbative expressions, that can be explained through an Operator Product Expansion as the influence of a non gauge invariant mass dimension two condensate. The relationship of this condensate with...