Status of Leading-Order Hadronic Vacuum Polarization Dispersion Calculation

TL;DR

This paper reviews the current status of calculating the leading-order hadronic vacuum polarization contribution to the muon g-2 using dispersion relations and experimental data, highlighting uncertainties and recent developments.

Contribution

It provides an updated overview of the dispersion integral calculations for the hadronic contribution to muon g-2 and discusses recent results and unresolved issues.

Findings

The hadronic contribution remains the largest source of uncertainty in muon g-2 predictions.

Discrepancies between theoretical calculations and experimental measurements are around 2.4 to 3.6 standard deviations.

Recent data updates have been incorporated into the dispersion analysis.

Abstract

The leading-order hadronic contribution to the muon magnetic anomaly a_{\mu} = (g_{\mu} - 2)/2, calculated using a dispersion integral of e+e- annihilation data and tau decay data, is briefly reviewed. This contribution has the largest uncertainty to the predicted value of a_{\mu}, which differs from the experimental value by ~3.6 (2.4) standard deviations for the e+e- (tau) based analysis. New results since the last workshop and main open issues on the subject are discussed.