# Anomalous magnetic moment of the muon with dynamical QCD+QED

## TL;DR

This paper investigates the impact of dynamical QCD and QED effects on the hadronic vacuum polarization contribution to the muon's anomalous magnetic moment, aiming to reduce theoretical uncertainties and improve agreement with experiments.

## Contribution

It introduces a lattice QCD+QED framework with flavor breaking effects and performs extrapolations to the physical point for the muon g-2 calculation.

## Key findings

- Quantifies QED effects on hadronic vacuum polarization
- Performs SU(3) flavor breaking expansion fits
- Provides extrapolated results at physical quark masses

## Abstract

The current $3.5\sigma$ discrepancy between experimental and Standard Model determinations of the anomalous magnetic moment of the muon $a_\mu=(g-2)/2$ can only be extended to the discovery $5\sigma$ regime through a reduction of both experimental and theoretical uncertainties. On the theory side, this means a determination of the hadronic vacuum polarisation (HVP) contribution to better than 0.5%, a level of precision that demands the inclusion of QCD + QED effects to properly understand how the behaviour of quarks are modified when their electric charges are turned on. The QCDSF collaboration has generated an ensemble of configurations with dynamical QCD and QED fields with the specific aim of studying flavour breaking effects arising from differences in the quark masses and charges in physical quantities. Here we study these effects in a calculation of HVP around the SU(3) symmetric point. Furthermore, by performing partially-quenched simulations we are able to cover a larger range of quark masses and charges on these configurations and then fit the results to an SU(3) flavour breaking expansion. Subsequently, this allows for an extrapolation to the physical point.