Measurement of Hadronic Cross Sections at BESIII

TL;DR

This paper discusses measurements of hadronic cross sections at BESIII to improve the precision of the Standard Model prediction of the muon's anomalous magnetic moment, focusing on experimental methods and recent results.

Contribution

It presents new measurements of hadronic cross sections at BESIII using energy scans and Initial State Radiation, enhancing inputs for muon g-2 calculations.

Findings

Improved hadronic cross section measurements above 2 GeV.

Successful application of ISR method for cross section determination.

Recent results contribute to reducing uncertainties in muon g-2 predictions.

Abstract

The uncertainties of the Standard Model prediction of the anomalous magnetic moment of the muon are currently completely dominated by hadronic contributions. The largest contribution is due to the hadronic vacuum polarization. Hadronic cross sections measured at $e^+e^-$ colliders can be exploited as experimental input to improve the calculations, making use of the optical theorem. At the BESIII experiment in Beijing these cross sections are determined using different methods. At center-of-mass energies above 2 GeV exclusive and inclusive cross sections can be measured in an energy scan. Additionally, cross sections can be determined starting from the $\pi^+\pi^-$ mass threshold using the method of Initial State Radiation. An overview of the recent results and the status of the analyses is provided.