Can VMD improve the estimate of the muon g-2 ?

Abstract

We show that a VMD based theoretical input allows for a significantly improved accuracy for the hadronic vacuum polarization of the photon which contributes to the theoretical estimate of the muon g-2. We also show that the only experimental piece of information in the $τ$ decay which cannot be accounted for is the accepted value for ${\rm Br}(τ\ra ππν_τ)$, while the spectum lineshape is in agreement with expectations from $e^+ e^-$ annihilations.

6 pages, 1 figure Proceedings of the PhiPsi09, Oct. 13-16, 2009, Beijing, China