Measurement of hadronic cross sections at BABAR with ISR and implications for the muon (g-2)

TL;DR

This paper discusses BABAR's use of the ISR method to precisely measure hadronic cross sections, which are crucial for understanding the muon's anomalous magnetic moment, with significant implications for particle physics.

Contribution

It introduces a ratio-based ISR measurement technique that reduces systematic uncertainties in hadronic cross section measurements at BABAR.

Findings

Precise cross section measurements for e+e- to hadrons channels.

Application of results to the muon (g-2) anomaly.

Validation of the ISR method for hadronic studies.

Abstract

The ISR method has been largely exploited by the BABAR experiment, for measuring numerous channels of the cross section e+e- into hadrons. 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 the mu+mu-(gamma) one. This method allows to cancel many systematic uncertainties in the ratio, hence the precise measured cross sections. Many multihadronic channels have also been studied using the ISR method, and cross sections have been published. These experimental results have also been exploited for phenomenological studies, like the determination of the hadronic contribution to the anomalous magnetic moment of the muon (g-2)_mu.