Two-Photon Fusion Results at BESIII

TL;DR

This paper reviews two-photon processes in electron-positron collisions, highlighting their role in probing hadronic structures, measuring resonance properties, and contributing to the understanding of the muon g-2 discrepancy, with a focus on BESIII's future measurements.

Contribution

It provides a comprehensive review of two-photon process results and discusses upcoming measurements by the BESIII collaboration, emphasizing their importance for hadronic physics and muon g-2 studies.

Findings

Two-photon processes are vital for studying hadronic structures.

Discrepancies in muon g-2 motivate further two-photon measurements.

BESIII plans future measurements to improve understanding of these processes.

Abstract

Two-photon processes in electron-positron collisions of the form $e^+e^-\to e^+e^-X$ are a well-established tool for probing hadronic structure and provide a direct access to non-vector states in $e^+e^-$ collisions. Collisions of quasi real photons have been employed by several experimental collaborations to extract radiative widths of various hadronic resonances. Persistent discrepancies between Standard Model predictions and measurements of the muon anomalous magnetic moment $a_\mu = (g-2)\mu/2$ have renewed interest in theoretical predictions for $\gamma\gamma \to X$ processes, particularly with off-shell photons. These are essential for evaluating the hadronic light-by-light contribution to $a_\mu$. This work reviews results and outlines future two-photon measurements by the BESIII collaboration.