The SVZ-Expansion and Beyond

S. Narison (1)

1 LPTA - Laboratoire de Physique Théorique et Astroparticules

I discuss the standard SVZ-expansion of the QCD two-point correlators in terms of the QCD vacuum condensates and beyond it due to a new unflavoured 1/Q^2-term (tachyonic gluon mass squared \lambda^2) which modelizes the effects of uncalculated higher order perturbative terms. The approach is confronted with low-energy and lattice data. One can notice that, in the different examples studied here, high-dimension condensates are expected to deviate largely from their vacuum saturation (large N_c) values, while the new 1/Q^2-term due to \lambda^2 solves the hadronic mass scale hierarchy-puzzle encountered in the early SVZ-sum rule analysis and improves the low-energy phenomenology. From tau-decay data, one can extract the running strange quark mass m_s(2 GeV)=(93^{+29}_{-32}) MeV and a more accurate value of the QCD coupling \alpha_s(M_Z)=0.117+- 0.002.

Domaines: Physique des Hautes Energies - Expérience [hep-ex]; Physique des Hautes Energies - Réseau [hep-lat]; Physique des Hautes Energies - Phénoménologie [hep-ph]; Physique des Hautes Energies - Théorie [hep-th]; Physique Nucléaire Théorique [nucl-th]

S. Narison. The SVZ-Expansion and Beyond. Workshop Understanding Confinement, May 2005, Ringberg Castle, Germany. pp.1-7. ⟨in2p3-00025720⟩