Infrared-suppressed QCD coupling and the hadronic contribution to muon g-2

Understand

A variant of QCD with the coupling suppressed in the infrared (IR) regime, as suggested by large-volume lattice calculations of the Landau-gauge gluon and ghost dressing functions, is considered.

• The coupling is further restricted by the condition of approximate coincidence with perturbative QCD in the high momentum regime, and by the $\tau$-lepton semihadronic decay rate in the intermediate momentum regime, the rate which is evaluated by a renormalon-motivated resummation method.
• The obtained coupling turns out to be free of Landau singularities.
• The $D=4,6$ condensate values of the Adler function are then extracted by application of the Borel sum rules to the OPAL and ALEPH (V+A)-channel data of $\tau$-decay, and the corresponding V-channel condensate values are deduced as well.