A certain pattern of divergence of perturbative expansions in quantum field theories, related
to their small and large momentum behaviour, is known as renormalons. We review formal …

The modern status of basic low energy QCD parameters is reviewed. It is demonstrated that
the recent data allow one to determine the light quark mass ratios with an accuracy of 10 …

The total τ hadronic width can be accurately calculated using analyticity and the operator
product expansion. The theoretical analysis of this observable is updated to include all …

The aim of the book is to give an introduction to the method of QCD Spectral Sum Rules and
to review its developments. After some general introductory remarks, Chiral Symmetry, the …

We review the recent status of the QCD sum rule approach to study the properties of
hadrons in vacuum and in hot or dense matter. Special focus is laid on the progress made in …

This report summarizes the proceedings of the 2014 Mainz Institute for Theoretical Physics
(MITP) scientific program on" High precision fundamental constants at the TeV scale". The …

Hadronic τ decays provide a clean laboratory for the precise study of quantum
chromodynamics (QCD). Observables based on the spectral functions of hadronic τ decays …

The determination of α s from hadronic τ decays is revisited, with a special emphasis on the
question of higher-order perturbative corrections and different possibilities of resumming the …

The semileptonic decay rate of a heavy lepton is shown to be rigorously calculable by use of
perturbative QCD. Even the τ lepton is heavy enough for the perturbative approximation to …

We determine the strange quark condensate from lattice QCD for the first time and compare
its value<? format?> to that of the light quark and chiral condensates. The results come from …