V-A hadronic tau decays: A laboratory for the QCD vacuum

ALEPH/OPAL data on the V-A spectral functions from hadronic τ decays are used in connection with a set of Laplace transform sum rules (LSR) for fixing the size of the QCD vacuum condensates up to dimension 18. Our results favor the ones from large-Nc QCD within the minimal hadronic approximation (MHA) and show a violation of about a factor 2-5 of the vacuum saturation estimate of the dimension-six to -ten condensates. We scrutinize the different determinations of the QCD vacuum condensates using τ-decays data. After revisiting some of the existing results, we present coherent values of the condensates from different methods.