Hadronic part of the tau's ( g - 2) from QCD

Abstract

The hadronic part of the tau's ( g - 2), a H ( τ) , is relatively important due to the large mass of the lepton. A purely theoretical calculation of a H ( τ) , using QCD and the analytic properties of the vacuum polarization tensor is presented. We obtain a H ( τ) ≅ 3 × 10 −6 as compared to the pure QED contribution a QED ( τ) = 1.17319 × 10 −3.