Anomalous magnetic moment of the muon in a dispersive approach

TL;DR

This paper introduces a dispersive formalism to evaluate the hadronic light-by-light scattering contribution to the muon's anomalous magnetic moment, linking it to measurable processes via unitarity and analyticity.

Contribution

The paper presents a novel dispersive approach that relates the muon's magnetic moment correction to measurable hadronic processes, validated against existing two-loop calculations.

Findings

Formalism agrees with direct two-loop calculations.

Method relates correction to measurable hadronic processes.

Provides a new framework for evaluating muon g-2 contributions.

Abstract

We present a new general dispersive formalism for evaluating the hadronic light-by-light scattering contribution to the anomalous magnetic moment of the muon. In the suggested approach, this correction is related to the imaginary part of the muon's electromagnetic vertex function. The latter may be directly related to measurable hadronic processes by means of unitarity and analyticity. As a test we apply the introduced formalism to the case of meson pole exchanges and find agreement with the direct two-loop calculation.