Abstract:

The accuracy of the Standard Model prediction of the muonic anomalous magnetic moment,, is critically limited by second order loop effects from hadronic vacuum polarization. The hadronic contribution to is related via a dispersion relation to the hadronic production rate in annihilation. The recent developments in the evaluation of the corresponding dispersion integral are presented in this seminar. It is shown that significant improvement has been achieved in a series of three analyses: (i) application of CVC, i.e., use of spectral functions in addition to cross sections; (ii) extended use of perturbative QCD and; (iii) application of QCD sum rule techniques. Each of these steps is motivated by comparison with similar applications, in particular using hadronic decays, and the underlying assumptions and their uncertainties are discussed.