Review of Recent Calculations of the Hadronic Vacuum Polarisation Contribution

TL;DR

This paper reviews recent methods for calculating the hadronic vacuum polarization contribution to the muon magnetic anomaly, emphasizing dispersion relation approaches using $e^+e^-$ and tau data, with detailed isospin-breaking corrections.

Contribution

It provides a comprehensive review of recent calculations, including novel corrections for isospin-breaking effects in tau data.

Findings

Dispersion relation methods effectively incorporate $e^+e^-$ data.

Tau data, after corrections, offer an alternative input.

Isospin-breaking corrections are crucial for accurate results.

Abstract

Recent calculations of the hadronic vacuum polarisation contribution are reviewed. The focus is put on the leading-order contribution to the muon magnetic anomaly involving $e^+e^-$ annihilation cross section data as input to a dispersion relation approach. Alternative calculation including tau data is also discussed. The $\tau$ data are corrected for various isospin-breaking sources which are explicitly shown source by source.