Measurements of low energy e+e- hadronic cross sections and implications for the muon g-2

TL;DR

This paper reports precise measurements of low-energy e+e- hadronic cross sections using the BABAR experiment's ISR method, providing key data for calculating the hadronic contribution to the muon g-2 anomaly.

Contribution

BABAR pioneered the ratio-based ISR method for pi+pi- and K+K- channels, reducing systematic uncertainties in cross section measurements.

Findings

Precise cross section measurements for e+e- --> hadrons.

Implications for the hadronic contribution to muon g-2.

Enhanced understanding of low-energy hadronic interactions.

Abstract

Numerous channels of the cross section e+e- --> hadrons have been measured by the BABAR experiment using the ISR method. For the pi+pi-(gamma) and K+K-(gamma) channels, BABAR has pioneered the method based on the ratio between the hadronic mass spectra and mu+mu-(gamma). Many systematic uncertainties cancel in the ratio, hence the precise measured cross sections. These measurements have been exploited for phenomenological studies, like the determination of the hadronic contribution to the anomalous magnetic moment of the muon (g-2)_mu.